Move the Extension builtin to the builtin/ folder.

This CL moves Extension from ast:: to builtin::

Change-Id: Ica1e6f4f9229341b547011389d47ae3be9830b0d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/120362
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>

src/tint/BUILD.gn

@@ -277,6 +277,7 @@ libtint_source_set("libtint_program_src") {
   deps = [
     ":libtint_ast_hdrs",
     ":libtint_base_src",
+    ":libtint_builtins_src",
     ":libtint_constant_src",
     ":libtint_sem_src",
     ":libtint_text_src",
@@ -310,6 +311,7 @@ libtint_source_set("libtint_inspector_src") {
   deps = [
     ":libtint_ast_src",
     ":libtint_base_src",
+    ":libtint_builtins_src",
     ":libtint_program_src",
     ":libtint_sem_src",
     ":libtint_type_src",
@@ -468,7 +470,6 @@ libtint_source_set("libtint_ast_hdrs") {
     "ast/discard_statement.h",
     "ast/enable.h",
     "ast/expression.h",
-    "ast/extension.h",
     "ast/float_literal_expression.h",
     "ast/for_loop_statement.h",
     "ast/function.h",
@@ -554,7 +555,6 @@ libtint_source_set("libtint_ast_src") {
     "ast/discard_statement.cc",
     "ast/enable.cc",
     "ast/expression.cc",
-    "ast/extension.cc",
     "ast/float_literal_expression.cc",
     "ast/for_loop_statement.cc",
     "ast/function.cc",
@@ -685,6 +685,7 @@ libtint_source_set("libtint_sem_src") {
   deps = [
     ":libtint_ast_hdrs",
     ":libtint_base_src",
+    ":libtint_builtins_src",
     ":libtint_constant_src",
     ":libtint_type_src",
   ]
@@ -694,7 +695,10 @@ libtint_source_set("libtint_builtins_src") {
   sources = [
     "builtin/builtin_value.cc",
     "builtin/builtin_value.h",
+    "builtin/extension.cc",
+    "builtin/extension.h",
   ]
+  deps = [ ":libtint_base_src" ]
 }
 
 libtint_source_set("libtint_type_src") {
@@ -869,6 +873,7 @@ libtint_source_set("libtint_writer_src") {
   deps = [
     ":libtint_ast_src",
     ":libtint_base_src",
+    ":libtint_builtins_src",
     ":libtint_inspector_src",
     ":libtint_program_src",
     ":libtint_sem_src",
@@ -1232,7 +1237,6 @@ if (tint_build_unittests) {
       "ast/diagnostic_directive_test.cc",
       "ast/discard_statement_test.cc",
       "ast/enable_test.cc",
-      "ast/extension_test.cc",
       "ast/float_literal_expression_test.cc",
       "ast/for_loop_statement_test.cc",
       "ast/function_test.cc",
@@ -1282,7 +1286,10 @@ if (tint_build_unittests) {
   }
 
   tint_unittests_source_set("tint_unittests_builtins_src") {
-    sources = [ "builtin/builtin_value_test.cc" ]
+    sources = [
+      "builtin/builtin_value_test.cc",
+      "builtin/extension_test.cc",
+    ]
     deps = [ ":libtint_builtins_src" ]
   }
 
@@ -1373,6 +1380,7 @@ if (tint_build_unittests) {
     ]
     deps = [
       ":libtint_base_src",
+      ":libtint_builtins_src",
       ":libtint_transform_src",
       ":tint_unittests_ast_src",
     ]

src/tint/CMakeLists.txt

@@ -549,8 +549,8 @@ list(APPEND TINT_LIB_SRCS
 )
 
 tint_generated(builtin/builtin_value BENCH TEST)
+tint_generated(builtin/extension BENCH TEST)
 tint_generated(ast/diagnostic_control BENCH TEST)
-tint_generated(ast/extension BENCH TEST)
 tint_generated(ast/interpolate_attribute BENCH TEST)
 tint_generated(resolver/init_conv_intrinsic)
 tint_generated(sem/builtin_type)

src/tint/ast/enable.cc

@@ -20,7 +20,7 @@ TINT_INSTANTIATE_TYPEINFO(tint::ast::Enable);
 
 namespace tint::ast {
 
-Enable::Enable(ProgramID pid, NodeID nid, const Source& src, Extension ext)
+Enable::Enable(ProgramID pid, NodeID nid, const Source& src, builtin::Extension ext)
     : Base(pid, nid, src), extension(ext) {}
 
 Enable::Enable(Enable&&) = default;

src/tint/ast/enable.h

@@ -19,8 +19,8 @@
 #include <utility>
 #include <vector>
 
-#include "src/tint/ast/extension.h"
 #include "src/tint/ast/node.h"
+#include "src/tint/builtin/extension.h"
 
 namespace tint::ast {
 
@@ -36,7 +36,7 @@ class Enable final : public Castable<Enable, Node> {
     /// @param nid the unique node identifier
     /// @param src the source of this node
     /// @param ext the extension
-    Enable(ProgramID pid, NodeID nid, const Source& src, Extension ext);
+    Enable(ProgramID pid, NodeID nid, const Source& src, builtin::Extension ext);
     /// Move constructor
     Enable(Enable&&);
 
@@ -49,7 +49,7 @@ class Enable final : public Castable<Enable, Node> {
     const Enable* Clone(CloneContext* ctx) const override;
 
     /// The extension name
-    const Extension extension;
+    const builtin::Extension extension;
 };
 
 }  // namespace tint::ast

src/tint/ast/enable_test.cc

@@ -22,12 +22,12 @@ namespace {
 using EnableTest = TestHelper;
 
 TEST_F(EnableTest, Creation) {
-    auto* ext = create<ast::Enable>(Source{{{20, 2}, {20, 5}}}, Extension::kF16);
+    auto* ext = create<ast::Enable>(Source{{{20, 2}, {20, 5}}}, builtin::Extension::kF16);
     EXPECT_EQ(ext->source.range.begin.line, 20u);
     EXPECT_EQ(ext->source.range.begin.column, 2u);
     EXPECT_EQ(ext->source.range.end.line, 20u);
     EXPECT_EQ(ext->source.range.end.column, 5u);
-    EXPECT_EQ(ext->extension, Extension::kF16);
+    EXPECT_EQ(ext->extension, builtin::Extension::kF16);
 }
 
 }  // namespace

src/tint/ast/module_test.cc

@@ -135,9 +135,9 @@ TEST_F(ModuleTest, CloneOrder) {
 }
 
 TEST_F(ModuleTest, Directives) {
-    auto* enable_1 = Enable(ast::Extension::kF16);
+    auto* enable_1 = Enable(builtin::Extension::kF16);
     auto* diagnostic_1 = DiagnosticDirective(DiagnosticSeverity::kWarning, "foo");
-    auto* enable_2 = Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+    auto* enable_2 = Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
     auto* diagnostic_2 = DiagnosticDirective(DiagnosticSeverity::kOff, "bar");
 
     this->SetResolveOnBuild(false);

src/tint/builtin/extension.cc

@@ -15,14 +15,14 @@
 ////////////////////////////////////////////////////////////////////////////////
 // File generated by tools/src/cmd/gen
 // using the template:
-//   src/tint/ast/extension.cc.tmpl
+//   src/tint/builtin/extension.cc.tmpl
 //
 // Do not modify this file directly
 ////////////////////////////////////////////////////////////////////////////////
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 
 /// ParseExtension parses a Extension from a string.
 /// @param str the string to parse
@@ -64,4 +64,4 @@ std::ostream& operator<<(std::ostream& out, Extension value) {
     return out << "<unknown>";
 }
 
-}  // namespace tint::ast
+}  // namespace tint::builtin

src/tint/builtin/extension.cc.tmpl

@@ -11,12 +11,12 @@ See:
 {{- Import "src/tint/templates/enums.tmpl.inc" -}}
 {{- $enum := (Sem.Enum "extension") -}}
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 
 {{ Eval "ParseEnum" $enum}}
 
 {{ Eval "EnumOStream" $enum}}
 
-}  // namespace tint::ast
+}  // namespace tint::builtin

src/tint/builtin/extension.h

@@ -15,19 +15,19 @@
 ////////////////////////////////////////////////////////////////////////////////
 // File generated by tools/src/cmd/gen
 // using the template:
-//   src/tint/ast/extension.h.tmpl
+//   src/tint/builtin/extension.h.tmpl
 //
 // Do not modify this file directly
 ////////////////////////////////////////////////////////////////////////////////
 
-#ifndef SRC_TINT_AST_EXTENSION_H_
-#define SRC_TINT_AST_EXTENSION_H_
+#ifndef SRC_TINT_BUILTIN_EXTENSION_H_
+#define SRC_TINT_BUILTIN_EXTENSION_H_
 
 #include <ostream>
 
 #include "src/tint/utils/unique_vector.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 
 /// An enumerator of WGSL extensions
 /// @see src/tint/intrinsics.def for extension descriptions
@@ -61,6 +61,6 @@ constexpr const char* kExtensionStrings[] = {
 // A unique vector of extensions
 using Extensions = utils::UniqueVector<Extension, 4>;
 
-}  // namespace tint::ast
+}  // namespace tint::builtin
 
-#endif  // SRC_TINT_AST_EXTENSION_H_
+#endif  // SRC_TINT_BUILTIN_EXTENSION_H_

src/tint/builtin/extension.h.tmpl

@@ -11,14 +11,14 @@ See:
 {{- Import "src/tint/templates/enums.tmpl.inc" -}}
 {{- $enum := (Sem.Enum "extension") -}}
 
-#ifndef SRC_TINT_AST_EXTENSION_H_
-#define SRC_TINT_AST_EXTENSION_H_
+#ifndef SRC_TINT_BUILTIN_EXTENSION_H_
+#define SRC_TINT_BUILTIN_EXTENSION_H_
 
 #include <ostream>
 
 #include "src/tint/utils/unique_vector.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 
 /// An enumerator of WGSL extensions
 /// @see src/tint/intrinsics.def for extension descriptions
@@ -27,6 +27,6 @@ namespace tint::ast {
 // A unique vector of extensions
 using Extensions = utils::UniqueVector<Extension, 4>;
 
-}  // namespace tint::ast
+}  // namespace tint::builtin
 
-#endif  // SRC_TINT_AST_EXTENSION_H_
+#endif  // SRC_TINT_BUILTIN_EXTENSION_H_

src/tint/builtin/extension_bench.cc

@@ -15,18 +15,18 @@
 ////////////////////////////////////////////////////////////////////////////////
 // File generated by tools/src/cmd/gen
 // using the template:
-//   src/tint/ast/extension_bench.cc.tmpl
+//   src/tint/builtin/extension_bench.cc.tmpl
 //
 // Do not modify this file directly
 ////////////////////////////////////////////////////////////////////////////////
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
 
 #include <array>
 
 #include "benchmark/benchmark.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 namespace {
 
 void ExtensionParser(::benchmark::State& state) {
@@ -78,4 +78,4 @@ void ExtensionParser(::benchmark::State& state) {
 BENCHMARK(ExtensionParser);
 
 }  // namespace
-}  // namespace tint::ast
+}  // namespace tint::builtin

src/tint/builtin/extension_bench.cc.tmpl

@@ -11,16 +11,16 @@ See:
 {{- Import "src/tint/templates/enums.tmpl.inc" -}}
 {{- $enum := (Sem.Enum "extension") -}}
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
 
 #include <array>
 
 #include "benchmark/benchmark.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 namespace {
 
 {{ Eval "BenchmarkParseEnum" $enum }}
 
 }  // namespace
-}  // namespace tint::ast
+}  // namespace tint::builtin

src/tint/builtin/extension_test.cc

@@ -15,19 +15,20 @@
 ////////////////////////////////////////////////////////////////////////////////
 // File generated by tools/src/cmd/gen
 // using the template:
-//   src/tint/ast/extension_test.cc.tmpl
+//   src/tint/builtin/extension_test.cc.tmpl
 //
 // Do not modify this file directly
 ////////////////////////////////////////////////////////////////////////////////
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
+
+#include <gtest/gtest.h>
 
 #include <string>
 
-#include "src/tint/ast/test_helper.h"
 #include "src/tint/utils/string.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 namespace {
 
 namespace parse_print_tests {
@@ -92,4 +93,4 @@ INSTANTIATE_TEST_SUITE_P(ValidCases, ExtensionPrintTest, testing::ValuesIn(kVali
 }  // namespace parse_print_tests
 
 }  // namespace
-}  // namespace tint::ast
+}  // namespace tint::builtin

src/tint/builtin/extension_test.cc.tmpl

@@ -11,17 +11,18 @@ See:
 {{- Import "src/tint/templates/enums.tmpl.inc" -}}
 {{- $enum := (Sem.Enum "extension") -}}
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
+
+#include <gtest/gtest.h>
 
 #include <string>
 
-#include "src/tint/ast/test_helper.h"
 #include "src/tint/utils/string.h"
 
-namespace tint::ast {
+namespace tint::builtin {
 namespace {
 
 {{ Eval "TestParsePrintEnum" $enum}}
 
 }  // namespace
-}  // namespace tint::ast
+}  // namespace tint::builtin

src/tint/cmd/main.cc

@@ -734,7 +734,7 @@ bool GenerateHlsl(const tint::Program* program, const Options& options) {
                 auto enable_list = program->AST().Enables();
                 bool dxc_require_16bit_types = false;
                 for (auto enable : enable_list) {
-                    if (enable->extension == tint::ast::Extension::kF16) {
+                    if (enable->extension == tint::builtin::Extension::kF16) {
                         dxc_require_16bit_types = true;
                         break;
                     }

src/tint/inspector/inspector.cc

@@ -19,7 +19,6 @@
 
 #include "src/tint/ast/bool_literal_expression.h"
 #include "src/tint/ast/call_expression.h"
-#include "src/tint/ast/extension.h"
 #include "src/tint/ast/float_literal_expression.h"
 #include "src/tint/ast/id_attribute.h"
 #include "src/tint/ast/identifier.h"
@@ -29,6 +28,7 @@
 #include "src/tint/ast/module.h"
 #include "src/tint/ast/override.h"
 #include "src/tint/ast/var.h"
+#include "src/tint/builtin/extension.h"
 #include "src/tint/sem/call.h"
 #include "src/tint/sem/function.h"
 #include "src/tint/sem/module.h"

src/tint/inspector/inspector_test.cc

@@ -289,7 +289,7 @@ TEST_P(InspectorGetEntryPointComponentAndCompositionTest, Test) {
     std::function<ast::Type()> tint_type = GetTypeFunction(component, composition);
 
     if (component == ComponentType::kF16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
     }
 
     auto* in_var = Param("in_var", tint_type(),

src/tint/ir/builder_impl_test.cc

@@ -1509,7 +1509,7 @@ TEST_F(IR_BuilderImplTest, EmitLiteral_F32) {
 }
 
 TEST_F(IR_BuilderImplTest, EmitLiteral_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto* expr = Expr(1.2_h);
     GlobalVar("a", ty.f16(), type::AddressSpace::kPrivate, expr);
 

src/tint/program_builder.h

@@ -42,7 +42,6 @@
 #include "src/tint/ast/disable_validation_attribute.h"
 #include "src/tint/ast/discard_statement.h"
 #include "src/tint/ast/enable.h"
-#include "src/tint/ast/extension.h"
 #include "src/tint/ast/float_literal_expression.h"
 #include "src/tint/ast/for_loop_statement.h"
 #include "src/tint/ast/id_attribute.h"
@@ -74,6 +73,7 @@
 #include "src/tint/ast/variable_decl_statement.h"
 #include "src/tint/ast/while_statement.h"
 #include "src/tint/ast/workgroup_attribute.h"
+#include "src/tint/builtin/extension.h"
 #include "src/tint/constant/composite.h"
 #include "src/tint/constant/splat.h"
 #include "src/tint/constant/value.h"
@@ -2036,7 +2036,7 @@ class ProgramBuilder {
     /// Adds the extension to the list of enable directives at the top of the module.
     /// @param ext the extension to enable
     /// @return an `ast::Enable` enabling the given extension.
-    const ast::Enable* Enable(ast::Extension ext) {
+    const ast::Enable* Enable(builtin::Extension ext) {
         auto* enable = create<ast::Enable>(ext);
         AST().AddEnable(enable);
         return enable;
@@ -2046,7 +2046,7 @@ class ProgramBuilder {
     /// @param source the enable source
     /// @param ext the extension to enable
     /// @return an `ast::Enable` enabling the given extension.
-    const ast::Enable* Enable(const Source& source, ast::Extension ext) {
+    const ast::Enable* Enable(const Source& source, builtin::Extension ext) {
         auto* enable = create<ast::Enable>(source, ext);
         AST().AddEnable(enable);
         return enable;

src/tint/reader/wgsl/parser_impl.cc

@@ -422,14 +422,15 @@ Maybe<Void> ParserImpl::enable_directive() {
             return add_error(t.source(), "enable directives don't take parenthesis");
         }
 
-        auto extension = ast::Extension::kUndefined;
+        auto extension = builtin::Extension::kUndefined;
         if (t.Is(Token::Type::kF16)) {
             // `f16` is a valid extension name and also a keyword
             synchronized_ = true;
             next();
-            extension = ast::Extension::kF16;
+            extension = builtin::Extension::kF16;
         } else {
-            auto ext = expect_enum("extension", ast::ParseExtension, ast::kExtensionStrings);
+            auto ext =
+                expect_enum("extension", builtin::ParseExtension, builtin::kExtensionStrings);
             if (ext.errored) {
                 return Failure::kErrored;
             }

src/tint/reader/wgsl/parser_impl_enable_directive_test.cc

@@ -30,7 +30,7 @@ TEST_F(EnableDirectiveTest, Valid) {
     auto& ast = program.AST();
     ASSERT_EQ(ast.Enables().Length(), 1u);
     auto* enable = ast.Enables()[0];
-    EXPECT_EQ(enable->extension, ast::Extension::kF16);
+    EXPECT_EQ(enable->extension, builtin::Extension::kF16);
     ASSERT_EQ(ast.GlobalDeclarations().Length(), 1u);
     EXPECT_EQ(ast.GlobalDeclarations()[0], enable);
 }
@@ -48,8 +48,8 @@ enable f16;
     ASSERT_EQ(ast.Enables().Length(), 2u);
     auto* enable_a = ast.Enables()[0];
     auto* enable_b = ast.Enables()[1];
-    EXPECT_EQ(enable_a->extension, ast::Extension::kF16);
-    EXPECT_EQ(enable_b->extension, ast::Extension::kF16);
+    EXPECT_EQ(enable_a->extension, builtin::Extension::kF16);
+    EXPECT_EQ(enable_b->extension, builtin::Extension::kF16);
     ASSERT_EQ(ast.GlobalDeclarations().Length(), 2u);
     EXPECT_EQ(ast.GlobalDeclarations()[0], enable_a);
     EXPECT_EQ(ast.GlobalDeclarations()[1], enable_b);
@@ -168,7 +168,7 @@ enable f16;
     // Accept the enable directive although it caused an error
     ASSERT_EQ(ast.Enables().Length(), 1u);
     auto* enable = ast.Enables()[0];
-    EXPECT_EQ(enable->extension, ast::Extension::kF16);
+    EXPECT_EQ(enable->extension, builtin::Extension::kF16);
     ASSERT_EQ(ast.GlobalDeclarations().Length(), 2u);
     EXPECT_EQ(ast.GlobalDeclarations()[1], enable);
 }
@@ -188,7 +188,7 @@ enable f16;
     // Accept the enable directive although it cause an error
     ASSERT_EQ(ast.Enables().Length(), 1u);
     auto* enable = ast.Enables()[0];
-    EXPECT_EQ(enable->extension, ast::Extension::kF16);
+    EXPECT_EQ(enable->extension, builtin::Extension::kF16);
     ASSERT_EQ(ast.GlobalDeclarations().Length(), 1u);
     EXPECT_EQ(ast.GlobalDeclarations()[0], enable);
 }

src/tint/resolver/address_space_layout_validation_test.cc

@@ -371,7 +371,7 @@ TEST_F(ResolverAddressSpaceLayoutValidationTest, UniformBuffer_Vec3F16MemberOffs
     // @group(0) @binding(0)
     // var<uniform> a : ScalarPackedAtEndOfVec3;
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("ScalarPackedAtEndOfVec3", utils::Vector{
                                              Member("v", ty.vec3(ty.f16())),
@@ -568,7 +568,7 @@ TEST_F(ResolverAddressSpaceLayoutValidationTest, PushConstant_UnalignedMember) {
     //     @align(1) b : f32;
     // };
     // var<push_constant> a : S;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Structure(
         Source{{12, 34}}, "S",
         utils::Vector{Member("a", ty.f32(), utils::Vector{MemberSize(5_a)}),
@@ -595,7 +595,7 @@ TEST_F(ResolverAddressSpaceLayoutValidationTest, PushConstant_Aligned) {
     //     @align(4) b : f32;
     // };
     // var<push_constant> a : S;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Structure("S", utils::Vector{Member("a", ty.f32(), utils::Vector{MemberSize(5_a)}),
                                  Member("b", ty.f32(), utils::Vector{MemberAlign(4_i)})});
     GlobalVar("a", ty("S"), type::AddressSpace::kPushConstant);

src/tint/resolver/address_space_validation_test.cc

@@ -249,7 +249,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_IntScalar) {
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_F16) {
     // enable f16;
     // var<storage> g : f16;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("g", ty.f16(), type::AddressSpace::kStorage, Binding(0_a), Group(0_a));
 
@@ -259,7 +259,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_F16) {
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_F16) {
     // enable f16;
     // type t = ptr<storage, f16>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Alias("t", ty.pointer(ty.f16(), type::AddressSpace::kStorage));
 
@@ -270,7 +270,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_F16Alias) {
     // enable f16;
     // type a = f16;
     // var<storage, read> g : a;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Alias("a", ty.f16());
     GlobalVar("g", ty("a"), type::AddressSpace::kStorage, Binding(0_a), Group(0_a));
@@ -282,7 +282,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_F16Alias) {
     // enable f16;
     // type a = f16;
     // type t = ptr<storage, a>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Alias("a", ty.f16());
     Alias("t", ty.pointer(ty("a"), type::AddressSpace::kStorage));
@@ -306,7 +306,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_VectorF32) {
 
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_VectorF16) {
     // var<storage> g : vec4<f16>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     GlobalVar("g", ty.vec(ty.f16(), 4u), type::AddressSpace::kStorage, Binding(0_a), Group(0_a));
 
     ASSERT_TRUE(r()->Resolve()) << r()->error();
@@ -314,7 +314,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_VectorF16) {
 
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_VectorF16) {
     // type t = ptr<storage, vec4<f16>>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     Alias("t", ty.pointer(ty.vec(ty.f16(), 4u), type::AddressSpace::kStorage));
 
     ASSERT_TRUE(r()->Resolve()) << r()->error();
@@ -343,7 +343,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_ArrayF16) {
     // enable f16;
     // struct S{ a : f16 };
     // var<storage, read> g : array<S, 3u>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("a", ty.f16())});
     GlobalVar("g", ty.array(ty("S"), 3_u), type::AddressSpace::kStorage, type::Access::kRead,
@@ -356,7 +356,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_ArrayF16) {
     // enable f16;
     // struct S{ a : f16 };
     // type t = ptr<storage, read, array<S, 3u>>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("a", ty.f16())});
     Alias("t",
@@ -412,7 +412,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_StructI32Aliases
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_StructF16) {
     // struct S { x : f16 };
     // var<storage, read> g : S;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     GlobalVar("g", ty("S"), type::AddressSpace::kStorage, type::Access::kRead, Binding(0_a),
@@ -424,7 +424,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_StructF16) {
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_StructF16) {
     // struct S { x : f16 };
     // type t = ptr<storage, read, S>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     Alias("t", ty.pointer(ty("S"), type::AddressSpace::kStorage, type::Access::kRead));
@@ -436,7 +436,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_Storage_StructF16Alias
     // struct S { x : f16 };
     // type a1 = S;
     // var<storage, read> g : a1;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     Alias("a1", ty("S"));
@@ -451,7 +451,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_Storage_StructF16Aliases
     // struct S { x : f16 };
     // type a1 = S;
     // type t = ptr<storage, read, a1>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     Alias("a1", ty("S"));
@@ -675,7 +675,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferIntScalar)
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_UniformBufferF16) {
     // enable f16;
     // var<uniform> g : f16;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("g", ty.f16(), type::AddressSpace::kUniform, Binding(0_a), Group(0_a));
 
@@ -685,7 +685,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_UniformBufferF16) {
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferF16) {
     // enable f16;
     // type t = ptr<uniform, f16>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Alias("t", ty.pointer(ty.f16(), type::AddressSpace::kUniform));
 
@@ -709,7 +709,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferVectorF32)
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_UniformBufferVectorF16) {
     // enable f16;
     // var<uniform> g : vec4<f16>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kUniform, Binding(0_a), Group(0_a));
 
@@ -719,7 +719,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_UniformBufferVectorF16
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferVectorF16) {
     // enable f16;
     // type t = ptr<uniform, vec4<f16>>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Alias("t", ty.pointer(ty.vec4<f16>(), type::AddressSpace::kUniform));
 
@@ -754,7 +754,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_UniformBufferArrayF16)
     //   @size(16) f : f16;
     // }
     // var<uniform> g : array<S, 3u>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("a", ty.f16(), utils::Vector{MemberSize(16_a)})});
     GlobalVar("g", ty.array(ty("S"), 3_u), type::AddressSpace::kUniform, Binding(0_a), Group(0_a));
@@ -768,7 +768,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferArrayF16) {
     //   @size(16) f : f16;
     // }
     // type t = ptr<uniform, array<S, 3u>>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("a", ty.f16(), utils::Vector{MemberSize(16_a)})});
     Alias("t", ty.pointer(ty.array(ty("S"), 3_u), type::AddressSpace::kUniform));
@@ -820,7 +820,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_UniformBufferStructF16
     // enable f16;
     // struct S { x : f16 };
     // var<uniform> g : S;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     GlobalVar("g", ty("S"), type::AddressSpace::kUniform, Binding(0_a), Group(0_a));
@@ -832,7 +832,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferStructF16)
     // enable f16;
     // struct S { x : f16 };
     // type t = ptr<uniform, S>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     Alias("t", ty.pointer(ty("S"), type::AddressSpace::kUniform));
@@ -845,7 +845,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_UniformBufferStructF16
     // struct S { x : f16 };
     // type a1 = S;
     // var<uniform> g : a1;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     Alias("a1", ty("S"));
@@ -859,7 +859,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferStructF16Al
     // struct S { x : f16 };
     // type a1 = S;
     // type t = ptr<uniform, a1>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{Member("x", ty.f16())});
     Alias("a1", ty("S"));
@@ -871,7 +871,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_UniformBufferStructF16Al
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantBool) {
     // enable chromium_experimental_push_constant;
     // var<push_constant> g : bool;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar(Source{{56, 78}}, "g", ty.bool_(Source{{12, 34}}), type::AddressSpace::kPushConstant);
 
     ASSERT_FALSE(r()->Resolve());
@@ -884,7 +884,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantBool) {
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantBool) {
     // enable chromium_experimental_push_constant;
     // type t = ptr<push_constant, bool>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Alias(Source{{56, 78}}, "t",
           ty.pointer(ty.bool_(Source{{12, 34}}), type::AddressSpace::kPushConstant));
 
@@ -899,8 +899,8 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantF16) {
     // enable f16;
     // enable chromium_experimental_push_constant;
     // var<push_constant> g : f16;
-    Enable(ast::Extension::kF16);
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kF16);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar("g", ty.f16(Source{{56, 78}}), type::AddressSpace::kPushConstant);
 
     ASSERT_FALSE(r()->Resolve());
@@ -912,8 +912,8 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantF16) {
     // enable f16;
     // enable chromium_experimental_push_constant;
     // type t = ptr<push_constant, f16>;
-    Enable(ast::Extension::kF16);
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kF16);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Alias("t", ty.pointer(ty.f16(Source{{56, 78}}), type::AddressSpace::kPushConstant));
 
     ASSERT_FALSE(r()->Resolve());
@@ -924,7 +924,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantF16) {
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantPointer) {
     // enable chromium_experimental_push_constant;
     // var<push_constant> g : ptr<private, f32>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar(Source{{56, 78}}, "g",
               ty.pointer(Source{{12, 34}}, ty.f32(), type::AddressSpace::kPrivate),
               type::AddressSpace::kPushConstant);
@@ -939,7 +939,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantPointer) {
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantPointer) {
     // enable chromium_experimental_push_constant;
     // type t = ptr<push_constant, ptr<private, f32>>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Alias(Source{{56, 78}}, "t",
           ty.pointer(ty.pointer(Source{{12, 34}}, ty.f32(), type::AddressSpace::kPrivate),
                      type::AddressSpace::kPushConstant));
@@ -954,7 +954,7 @@ note: while instantiating ptr<push_constant, ptr<private, f32, read_write>, read
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantIntScalar) {
     // enable chromium_experimental_push_constant;
     // var<push_constant> g : i32;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar("g", ty.i32(), type::AddressSpace::kPushConstant);
 
     ASSERT_TRUE(r()->Resolve()) << r()->error();
@@ -963,7 +963,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantIntScalar)
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantIntScalar) {
     // enable chromium_experimental_push_constant;
     // type t = ptr<push_constant, i32>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Alias("t", ty.pointer(ty.i32(), type::AddressSpace::kPushConstant));
 
     ASSERT_TRUE(r()->Resolve()) << r()->error();
@@ -972,7 +972,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantIntScalar) {
 TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantVectorF32) {
     // enable chromium_experimental_push_constant;
     // var<push_constant> g : vec4<f32>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar("g", ty.vec4<f32>(), type::AddressSpace::kPushConstant);
 
     ASSERT_TRUE(r()->Resolve()) << r()->error();
@@ -981,7 +981,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantVectorF32)
 TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantVectorF32) {
     // enable chromium_experimental_push_constant;
     // var<push_constant> g : vec4<f32>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Alias("t", ty.pointer(ty.vec4<f32>(), type::AddressSpace::kPushConstant));
 
     ASSERT_TRUE(r()->Resolve()) << r()->error();
@@ -991,7 +991,7 @@ TEST_F(ResolverAddressSpaceValidationTest, GlobalVariable_PushConstantArrayF32)
     // enable chromium_experimental_push_constant;
     // struct S { a : f32}
     // var<push_constant> g : array<S, 3u>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Structure("S", utils::Vector{Member("a", ty.f32())});
     GlobalVar("g", ty.array(ty("S"), 3_u), type::AddressSpace::kPushConstant);
 
@@ -1002,7 +1002,7 @@ TEST_F(ResolverAddressSpaceValidationTest, PointerAlias_PushConstantArrayF32) {
     // enable chromium_experimental_push_constant;
     // struct S { a : f32}
     // type t = ptr<push_constant, array<S, 3u>>;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     Structure("S", utils::Vector{Member("a", ty.f32())});
     Alias("t", ty.pointer(ty.array(ty("S"), 3_u), type::AddressSpace::kPushConstant));
 

src/tint/resolver/builtin_test.cc

@@ -471,7 +471,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, FourParams_Vector_f32) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, OneParam_Scalar_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto val = 0.5_h;
     if (param.name == std::string("acosh")) {
@@ -499,7 +499,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, OneParam_Scalar_f16) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, OneParam_Vector_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto val = param.name == std::string("acosh") ? vec3<f16>(1.0_h, 2.0_h, 3.0_h)
                                                   : vec3<f16>(0.5_h, 0.5_h, 0.8_h);
@@ -528,7 +528,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, OneParam_Vector_f16) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, TwoParams_Scalar_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call(param.name, 1_h, 1_h);
     WrapInFunction(call);
@@ -551,7 +551,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, TwoParams_Scalar_f16) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, TwoParams_Vector_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call(param.name, vec3<f16>(1_h, 1_h, 3_h), vec3<f16>(1_h, 1_h, 3_h));
     WrapInFunction(call);
@@ -577,7 +577,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, TwoParams_Vector_f16) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, ThreeParams_Scalar_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call(param.name, 0_h, 1_h, 2_h);
     WrapInFunction(call);
@@ -600,7 +600,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, ThreeParams_Scalar_f16) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, ThreeParams_Vector_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call(param.name, vec3<f16>(0_h, 0_h, 0_h), vec3<f16>(1_h, 1_h, 1_h),
                       vec3<f16>(2_h, 2_h, 2_h));
@@ -628,7 +628,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, ThreeParams_Vector_f16) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, FourParams_Scalar_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call(param.name, 1_h, 1_h, 1_h, 1_h);
     WrapInFunction(call);
@@ -651,7 +651,7 @@ TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, FourParams_Scalar_f16) {
 TEST_P(ResolverBuiltinTest_FloatBuiltin_IdenticalType, FourParams_Vector_f16) {
     auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call(param.name, vec3<f16>(1_h, 1_h, 3_h), vec3<f16>(1_h, 1_h, 3_h),
                       vec3<f16>(1_h, 1_h, 3_h), vec3<f16>(1_h, 1_h, 3_h));
@@ -745,7 +745,7 @@ TEST_F(ResolverBuiltinFloatTest, Cross_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, Cross_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("cross", vec3<f16>(1_h, 2_h, 3_h), vec3<f16>(1_h, 2_h, 3_h));
     WrapInFunction(call);
@@ -841,7 +841,7 @@ TEST_F(ResolverBuiltinFloatTest, Distance_Scalar_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, Distance_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("distance", 1_h, 1_h);
     WrapInFunction(call);
@@ -863,7 +863,7 @@ TEST_F(ResolverBuiltinFloatTest, Distance_Vector_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, Distance_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("distance", vec3<f16>(1_h, 1_h, 3_h), vec3<f16>(1_h, 1_h, 3_h));
     WrapInFunction(call);
@@ -949,7 +949,7 @@ TEST_F(ResolverBuiltinFloatTest, FrexpScalar_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, FrexpScalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("frexp", 1_h);
     WrapInFunction(call);
@@ -1013,7 +1013,7 @@ TEST_F(ResolverBuiltinFloatTest, FrexpVector_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, FrexpVector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("frexp", vec3<f16>());
     WrapInFunction(call);
@@ -1075,7 +1075,7 @@ TEST_F(ResolverBuiltinFloatTest, Length_Scalar_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, Length_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("length", 1_h);
     WrapInFunction(call);
@@ -1097,7 +1097,7 @@ TEST_F(ResolverBuiltinFloatTest, Length_FloatVector_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, Length_FloatVector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("length", vec3<f16>(1_h, 1_h, 3_h));
     WrapInFunction(call);
@@ -1152,7 +1152,7 @@ TEST_F(ResolverBuiltinFloatTest, Mix_VectorScalar_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, Mix_VectorScalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("mix", vec3<f16>(1_h, 1_h, 1_h), vec3<f16>(1_h, 1_h, 1_h), 4_h);
     WrapInFunction(call);
@@ -1198,7 +1198,7 @@ TEST_F(ResolverBuiltinFloatTest, ModfScalar_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, ModfScalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("modf", 1_h);
     WrapInFunction(call);
@@ -1262,7 +1262,7 @@ TEST_F(ResolverBuiltinFloatTest, ModfVector_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, ModfVector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("modf", vec3<f16>());
     WrapInFunction(call);
@@ -1372,7 +1372,7 @@ TEST_F(ResolverBuiltinFloatTest, Normalize_Vector_f32) {
 }
 
 TEST_F(ResolverBuiltinFloatTest, Normalize_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* call = Call("normalize", vec3<f16>(1_h, 1_h, 3_h));
     WrapInFunction(call);
@@ -1835,7 +1835,7 @@ TEST_F(ResolverBuiltinTest, Determinant_2x2_f32) {
 }
 
 TEST_F(ResolverBuiltinTest, Determinant_2x2_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("var", ty.mat2x2<f16>(), type::AddressSpace::kPrivate);
 
@@ -1861,7 +1861,7 @@ TEST_F(ResolverBuiltinTest, Determinant_3x3_f32) {
 }
 
 TEST_F(ResolverBuiltinTest, Determinant_3x3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("var", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
 
@@ -1887,7 +1887,7 @@ TEST_F(ResolverBuiltinTest, Determinant_4x4_f32) {
 }
 
 TEST_F(ResolverBuiltinTest, Determinant_4x4_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("var", ty.mat4x4<f16>(), type::AddressSpace::kPrivate);
 
@@ -1948,7 +1948,7 @@ TEST_F(ResolverBuiltinTest, Dot_Vec2_f32) {
 }
 
 TEST_F(ResolverBuiltinTest, Dot_Vec2_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("my_var", ty.vec2<f16>(), type::AddressSpace::kPrivate);
 

src/tint/resolver/builtin_validation_test.cc

@@ -523,7 +523,7 @@ using ResolverDP4aExtensionValidationTest = ResolverTest;
 TEST_F(ResolverDP4aExtensionValidationTest, Dot4I8PackedWithExtension) {
     // enable chromium_experimental_dp4a;
     // fn func { return dot4I8Packed(1u, 2u); }
-    Enable(ast::Extension::kChromiumExperimentalDp4A);
+    Enable(builtin::Extension::kChromiumExperimentalDp4A);
 
     Func("func", utils::Empty, ty.i32(),
          utils::Vector{
@@ -551,7 +551,7 @@ TEST_F(ResolverDP4aExtensionValidationTest, Dot4I8PackedWithoutExtension) {
 TEST_F(ResolverDP4aExtensionValidationTest, Dot4U8PackedWithExtension) {
     // enable chromium_experimental_dp4a;
     // fn func { return dot4U8Packed(1u, 2u); }
-    Enable(ast::Extension::kChromiumExperimentalDp4A);
+    Enable(builtin::Extension::kChromiumExperimentalDp4A);
 
     Func("func", utils::Empty, ty.u32(),
          utils::Vector{

src/tint/resolver/call_test.cc

@@ -82,7 +82,7 @@ static constexpr Params all_param_types[] = {
 };
 
 TEST_F(ResolverCallTest, Valid) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     utils::Vector<const ast::Parameter*, 4> params;
     utils::Vector<const ast::Expression*, 4> args;

src/tint/resolver/call_validation_test.cc

@@ -165,7 +165,7 @@ TEST_F(ResolverCallValidationTest,
     //   var v : S;
     //   foo(&v.m);
     // }
-    Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+    Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
     auto* S = Structure("S", utils::Vector{
                                  Member("m", ty.i32()),
                              });
@@ -346,7 +346,7 @@ TEST_F(ResolverCallValidationTest, LetPointer_NotWholeVar_WithFullPtrParametersE
     //   let p: ptr<function, i32> = &(v[0]);
     //   x(p);
     // }
-    Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+    Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
     Func("foo",
          utils::Vector{
              Param("p", ty.pointer<i32>(type::AddressSpace::kFunction)),
@@ -437,7 +437,7 @@ TEST_F(ResolverCallValidationTest, ComplexPointerChain_NotWholeVar_WithFullPtrPa
     //   let p3 = &(*p2)[0];
     //   foo(&*p);
     // }
-    Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+    Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
     Func("foo",
          utils::Vector{
              Param("p", ty.pointer<i32>(type::AddressSpace::kFunction)),

src/tint/resolver/const_eval_binary_op_test.cc

@@ -83,7 +83,7 @@ std::ostream& operator<<(std::ostream& o, const ErrorCase& c) {
 
 using ResolverConstEvalBinaryOpTest = ResolverTestWithParam<std::tuple<ast::BinaryOp, Case>>;
 TEST_P(ResolverConstEvalBinaryOpTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto op = std::get<0>(GetParam());
     auto& c = std::get<1>(GetParam());
 

src/tint/resolver/const_eval_builtin_test.cc

@@ -142,7 +142,7 @@ static Case E(std::initializer_list<ScalarTypes> sargs, std::string err) {
 using ResolverConstEvalBuiltinTest = ResolverTestWithParam<std::tuple<sem::BuiltinType, Case>>;
 
 TEST_P(ResolverConstEvalBuiltinTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto builtin = std::get<0>(GetParam());
     auto& c = std::get<1>(GetParam());

src/tint/resolver/const_eval_construction_test.cc

@@ -102,7 +102,7 @@ TEST_F(ResolverConstEvalTest, Scalar_f32) {
 }
 
 TEST_F(ResolverConstEvalTest, Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = Expr(9.9_h);
     WrapInFunction(expr);
@@ -146,7 +146,7 @@ Case C() {
 }
 using ResolverConstEvalZeroInitTest = ResolverTestWithParam<Case>;
 TEST_P(ResolverConstEvalZeroInitTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto& param = GetParam();
     auto ty = param.type(*this);
     auto* expr = Call(ty);
@@ -316,7 +316,7 @@ TEST_F(ResolverConstEvalTest, Vec3_ZeroInit_f32) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_ZeroInit_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>();
     WrapInFunction(expr);
@@ -483,7 +483,7 @@ TEST_F(ResolverConstEvalTest, Vec3_Splat_f32) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_Splat_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(9.9_h);
     WrapInFunction(expr);
@@ -719,7 +719,7 @@ TEST_F(ResolverConstEvalTest, Vec3_FullConstruct_f32) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_FullConstruct_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(1_h, 2_h, 3_h);
     WrapInFunction(expr);
@@ -1018,7 +1018,7 @@ TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f32_mixed_sign_0) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(1_h, vec2<f16>(2_h, 3_h));
     WrapInFunction(expr);
@@ -1053,7 +1053,7 @@ TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16_all_10) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(10_h, vec2<f16>(10_h, 10_h));
     WrapInFunction(expr);
@@ -1088,7 +1088,7 @@ TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16_all_10) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16_all_positive_0) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(0_h, vec2<f16>(0_h, 0_h));
     WrapInFunction(expr);
@@ -1123,7 +1123,7 @@ TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16_all_positive_0) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16_all_negative_0) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(vec2<f16>(-0_h, -0_h), -0_h);
     WrapInFunction(expr);
@@ -1158,7 +1158,7 @@ TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16_all_negative_0) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_MixConstruct_f16_mixed_sign_0) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(0_h, vec2<f16>(-0_h, 0_h));
     WrapInFunction(expr);
@@ -1341,7 +1341,7 @@ TEST_F(ResolverConstEvalTest, Mat2x3_ZeroInit_f32) {
 }
 
 TEST_F(ResolverConstEvalTest, Mat2x3_ZeroInit_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = mat2x3<f16>();
     WrapInFunction(expr);
@@ -1704,7 +1704,7 @@ static std::ostream& operator<<(std::ostream& o, const Case& c) {
 
 using ResolverConstEvalArrayInitTest = ResolverTestWithParam<Case>;
 TEST_P(ResolverConstEvalArrayInitTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto& param = GetParam();
     auto* expr = param.input.Expr(*this);
     auto* a = Const("a", expr);
@@ -1892,7 +1892,7 @@ TEST_F(ResolverConstEvalTest, Array_Struct_f32_Elements) {
 }
 
 TEST_F(ResolverConstEvalTest, Struct_ZeroInit) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto* s = Structure("S", utils::Vector{
                                  Member("a", ty.i32()),
                                  Member("b", ty.u32()),
@@ -1937,7 +1937,7 @@ TEST_F(ResolverConstEvalTest, Struct_ZeroInit) {
 }
 
 TEST_F(ResolverConstEvalTest, Struct_Nested_ZeroInit) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto* inner = Structure("Inner", utils::Vector{
                                          Member("a", ty.i32()),
                                          Member("b", ty.u32()),
@@ -2028,7 +2028,7 @@ TEST_F(ResolverConstEvalTest, Struct_I32s_ZeroInit) {
 }
 
 TEST_F(ResolverConstEvalTest, Struct_MixedScalars_ZeroInit) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{
                        Member("m1", ty.i32()),
@@ -2138,7 +2138,7 @@ TEST_F(ResolverConstEvalTest, Struct_VectorF32s_ZeroInit) {
 }
 
 TEST_F(ResolverConstEvalTest, Struct_MixedVectors_ZeroInit) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{
                        Member("m1", ty.vec2<i32>()),
@@ -2258,7 +2258,7 @@ TEST_F(ResolverConstEvalTest, Struct_Struct_ZeroInit) {
 }
 
 TEST_F(ResolverConstEvalTest, Struct_MixedScalars_Construct) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{
                        Member("m1", ty.i32()),
@@ -2315,7 +2315,7 @@ TEST_F(ResolverConstEvalTest, Struct_MixedScalars_Construct) {
 }
 
 TEST_F(ResolverConstEvalTest, Struct_MixedVectors_Construct) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Structure("S", utils::Vector{
                        Member("m1", ty.vec2<i32>()),

src/tint/resolver/const_eval_conversion_test.cc

@@ -289,7 +289,7 @@ TEST_F(ResolverConstEvalTest, Vec3_Convert_u32_to_f32) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_Convert_f16_to_i32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<i32>(vec3<f16>(1.1_h, 2.2_h, 3.3_h));
     WrapInFunction(expr);
@@ -324,7 +324,7 @@ TEST_F(ResolverConstEvalTest, Vec3_Convert_f16_to_i32) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_Convert_u32_to_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(vec3<u32>(10_u, 20_u, 30_u));
     WrapInFunction(expr);
@@ -425,7 +425,7 @@ TEST_F(ResolverConstEvalTest, Vec3_Convert_Large_f32_to_u32) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_Convert_Large_f32_to_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(Source{{12, 34}}, vec3<f32>(1e10_f, 0_f, 0_f));
     WrapInFunction(expr);
@@ -435,7 +435,7 @@ TEST_F(ResolverConstEvalTest, Vec3_Convert_Large_f32_to_f16) {
 }
 
 TEST_F(ResolverConstEvalTest, Vec3_Convert_Small_f32_to_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = vec3<f16>(vec3<f32>(1e-20_f, -2e-30_f, 3e-40_f));
     WrapInFunction(expr);

src/tint/resolver/const_eval_indexing_test.cc

@@ -68,7 +68,7 @@ static std::ostream& operator<<(std::ostream& o, const Case& c) {
 
 using ResolverConstEvalSwizzleTest = ResolverTestWithParam<Case>;
 TEST_P(ResolverConstEvalSwizzleTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto& param = GetParam();
     auto* expr = MemberAccessor(param.input.Expr(*this), param.swizzle);
     auto* a = Const("a", expr);

src/tint/resolver/const_eval_member_access_test.cc

@@ -263,7 +263,7 @@ static std::ostream& operator<<(std::ostream& o, const Case& c) {
 
 using ResolverConstEvalArrayAccessTest = ResolverTestWithParam<Case>;
 TEST_P(ResolverConstEvalArrayAccessTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto& param = GetParam();
     auto* expr = param.input.Expr(*this);
@@ -338,7 +338,7 @@ static std::ostream& operator<<(std::ostream& o, const Case& c) {
 
 using ResolverConstEvalVectorAccessTest = ResolverTestWithParam<Case>;
 TEST_P(ResolverConstEvalVectorAccessTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto& param = GetParam();
     auto* expr = param.input.Expr(*this);

src/tint/resolver/const_eval_unary_op_test.cc

@@ -42,7 +42,7 @@ Case C(T input, U expected) {
 using ResolverConstEvalUnaryOpTest = ResolverTestWithParam<std::tuple<ast::UnaryOp, Case>>;
 
 TEST_P(ResolverConstEvalUnaryOpTest, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto op = std::get<0>(GetParam());
     auto& c = std::get<1>(GetParam());

src/tint/resolver/dependency_graph_test.cc

@@ -1094,7 +1094,7 @@ TEST_F(ResolverDependencyGraphOrderedGlobalsTest, DirectiveFirst) {
     // a transform may produce such a AST tree that has some declarations before directive nodes.
     // DependencyGraph should deal with these cases.
     auto* var_1 = GlobalVar("SYMBOL1", ty.i32());
-    auto* enable = Enable(ast::Extension::kF16);
+    auto* enable = Enable(builtin::Extension::kF16);
     auto* var_2 = GlobalVar("SYMBOL2", ty.f32());
     auto* diagnostic = DiagnosticDirective(ast::DiagnosticSeverity::kWarning, "foo");
 

src/tint/resolver/entry_point_validation_test.cc

@@ -455,7 +455,7 @@ TEST_F(ResolverEntryPointValidationTest, VertexShaderMustReturnPosition) {
 TEST_F(ResolverEntryPointValidationTest, PushConstantAllowedWithEnable) {
     // enable chromium_experimental_push_constant;
     // var<push_constant> a : u32;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar("a", ty.u32(), type::AddressSpace::kPushConstant);
 
     EXPECT_TRUE(r()->Resolve());
@@ -485,7 +485,7 @@ TEST_F(ResolverEntryPointValidationTest, PushConstantOneVariableUsedInEntryPoint
     // @compute @workgroup_size(1) fn main() {
     //   _ = a;
     // }
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar("a", ty.u32(), type::AddressSpace::kPushConstant);
 
     Func("main", {}, ty.void_(), utils::Vector{Assign(Phony(), "a")},
@@ -503,7 +503,7 @@ TEST_F(ResolverEntryPointValidationTest, PushConstantTwoVariablesUsedInEntryPoin
     //   _ = a;
     //   _ = b;
     // }
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar(Source{{1, 2}}, "a", ty.u32(), type::AddressSpace::kPushConstant);
     GlobalVar(Source{{3, 4}}, "b", ty.u32(), type::AddressSpace::kPushConstant);
 
@@ -534,7 +534,7 @@ TEST_F(ResolverEntryPointValidationTest,
     //   uses_a();
     //   uses_b();
     // }
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar(Source{{1, 2}}, "a", ty.u32(), type::AddressSpace::kPushConstant);
     GlobalVar(Source{{3, 4}}, "b", ty.u32(), type::AddressSpace::kPushConstant);
 
@@ -567,7 +567,7 @@ TEST_F(ResolverEntryPointValidationTest, PushConstantTwoVariablesUsedInDifferent
     // @compute @workgroup_size(1) fn uses_b() {
     //   _ = a;
     // }
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar("a", ty.u32(), type::AddressSpace::kPushConstant);
     GlobalVar("b", ty.u32(), type::AddressSpace::kPushConstant);
 
@@ -624,7 +624,7 @@ TEST_P(TypeValidationTest, BareInputs) {
     // fn main(@location(0) @interpolate(flat) a : *) {}
     auto params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* a = Param("a", params.create_ast_type(*this),
                     utils::Vector{
@@ -655,7 +655,7 @@ TEST_P(TypeValidationTest, StructInputs) {
     // fn main(a : Input) {}
     auto params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* input = Structure("Input", utils::Vector{
                                          Member("a", params.create_ast_type(*this),
@@ -685,7 +685,7 @@ TEST_P(TypeValidationTest, BareOutputs) {
     // }
     auto params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Func(Source{{12, 34}}, "main", utils::Empty, params.create_ast_type(*this),
          utils::Vector{
@@ -715,7 +715,7 @@ TEST_P(TypeValidationTest, StructOutputs) {
     // }
     auto params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* output = Structure(
         "Output", utils::Vector{

src/tint/resolver/expression_kind_test.cc

@@ -220,7 +220,7 @@ TEST_P(ResolverExpressionKindTest, Test) {
             GlobalVar("v", ty("texture_storage_2d", "rgba8unorm", expr), Group(0_u), Binding(0_u));
             break;
         case Use::kAddressSpace:
-            Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+            Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
             Func("f", utils::Vector{Param("p", ty("ptr", expr, ty.f32()))}, ty.void_(),
                  utils::Empty);
             break;

src/tint/resolver/f16_extension_test.cc

@@ -27,7 +27,7 @@ using ResolverF16ExtensionTest = ResolverTest;
 TEST_F(ResolverF16ExtensionTest, TypeUsedWithExtension) {
     // enable f16;
     // var<private> v : f16;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("v", ty.f16(), type::AddressSpace::kPrivate);
 
@@ -45,7 +45,7 @@ TEST_F(ResolverF16ExtensionTest, TypeUsedWithoutExtension) {
 TEST_F(ResolverF16ExtensionTest, Vec2TypeUsedWithExtension) {
     // enable f16;
     // var<private> v : vec2<f16>;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("v", ty.vec2<f16>(), type::AddressSpace::kPrivate);
 
@@ -63,7 +63,7 @@ TEST_F(ResolverF16ExtensionTest, Vec2TypeUsedWithoutExtension) {
 TEST_F(ResolverF16ExtensionTest, Vec2TypeInitUsedWithExtension) {
     // enable f16;
     // var<private> v = vec2<f16>();
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("v", vec2<f16>(), type::AddressSpace::kPrivate);
 
@@ -81,7 +81,7 @@ TEST_F(ResolverF16ExtensionTest, Vec2TypeInitUsedWithoutExtension) {
 TEST_F(ResolverF16ExtensionTest, Vec2TypeConvUsedWithExtension) {
     // enable f16;
     // var<private> v = vec2<f16>(vec2<f32>());
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("v", vec2<f16>(vec2<f32>()), type::AddressSpace::kPrivate);
 
@@ -99,7 +99,7 @@ TEST_F(ResolverF16ExtensionTest, Vec2TypeConvUsedWithoutExtension) {
 TEST_F(ResolverF16ExtensionTest, F16LiteralUsedWithExtension) {
     // enable f16;
     // var<private> v = 16h;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("v", Expr(16_h), type::AddressSpace::kPrivate);
 
@@ -119,7 +119,7 @@ using ResolverF16ExtensionBuiltinTypeAliasTest = ResolverTestWithParam<const cha
 TEST_P(ResolverF16ExtensionBuiltinTypeAliasTest, Vec2hTypeUsedWithExtension) {
     // enable f16;
     // var<private> v : vec2h;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("v", ty(Source{{12, 34}}, GetParam()), type::AddressSpace::kPrivate);
 

src/tint/resolver/function_validation_test.cc

@@ -1081,7 +1081,7 @@ TEST_P(ResolverFunctionParameterValidationTest, AddressSpaceWithExtension) {
     auto& param = GetParam();
     auto ptr_type = ty("ptr", Ident(Source{{12, 34}}, param.address_space), ty.i32());
     auto* arg = Param(Source{{12, 34}}, "p", ptr_type);
-    Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+    Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
     Func("f", utils::Vector{arg}, ty.void_(), utils::Empty);
 
     if (param.expectation == Expectation::kAlwaysPass ||

src/tint/resolver/host_shareable_validation_test.cc

@@ -97,7 +97,7 @@ TEST_F(ResolverHostShareableValidationTest, NestedStructures) {
 }
 
 TEST_F(ResolverHostShareableValidationTest, NoError) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* i1 = Structure("I1", utils::Vector{
                                    Member(Source{{1, 1}}, "w1", ty.f32()),

src/tint/resolver/materialize_test.cc

@@ -312,7 +312,7 @@ using MaterializeAbstractNumericToConcreteType =
     MaterializeTest<std::tuple<Expectation, Method, Data>>;
 
 TEST_P(MaterializeAbstractNumericToConcreteType, Test) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     const auto& param = GetParam();
     const auto& expectation = std::get<0>(param);
@@ -1282,7 +1282,7 @@ TEST_F(MaterializeAbstractStructure, Modf_Vector_DefaultType) {
 TEST_F(MaterializeAbstractStructure, Modf_Scalar_ExplicitType) {
     // var v = modf(1_h); // v is __modf_result_f16
     // v = modf(1);       // __modf_result_f16 <- __modf_result_abstract
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto* call = Call("modf", 1_a);
     WrapInFunction(Decl(Var("v", Call("modf", 1_h))),  //
                    Assign("v", call));
@@ -1301,7 +1301,7 @@ TEST_F(MaterializeAbstractStructure, Modf_Scalar_ExplicitType) {
 TEST_F(MaterializeAbstractStructure, Modf_Vector_ExplicitType) {
     // var v = modf(vec2(1_h)); // v is __modf_result_vec2_f16
     // v = modf(vec2(1));       // __modf_result_vec2_f16 <- __modf_result_vec2_abstract
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto* call = Call("modf", Call(ty.vec2<Infer>(), 1_a));
     WrapInFunction(Decl(Var("v", Call("modf", Call(ty.vec2<Infer>(), 1_h)))), Assign("v", call));
     ASSERT_TRUE(r()->Resolve()) << r()->error();
@@ -1363,7 +1363,7 @@ TEST_F(MaterializeAbstractStructure, Frexp_Vector_DefaultType) {
 TEST_F(MaterializeAbstractStructure, Frexp_Scalar_ExplicitType) {
     // var v = frexp(1_h); // v is __frexp_result_f16
     // v = frexp(1);       // __frexp_result_f16 <- __frexp_result_abstract
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto* call = Call("frexp", 1_a);
     WrapInFunction(Decl(Var("v", Call("frexp", 1_h))),  //
                    Assign("v", call));
@@ -1384,7 +1384,7 @@ TEST_F(MaterializeAbstractStructure, Frexp_Scalar_ExplicitType) {
 TEST_F(MaterializeAbstractStructure, Frexp_Vector_ExplicitType) {
     // var v = frexp(vec2(1_h)); // v is __frexp_result_vec2_f16
     // v = frexp(vec2(1));       // __frexp_result_vec2_f16 <- __frexp_result_vec2_abstract
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     auto* call = Call("frexp", Call(ty.vec2<Infer>(), 1_a));
     WrapInFunction(Decl(Var("v", Call("frexp", Call(ty.vec2<Infer>(), 1_h)))), Assign("v", call));
     ASSERT_TRUE(r()->Resolve()) << r()->error();

src/tint/resolver/override_test.cc

@@ -103,7 +103,7 @@ TEST_F(ResolverOverrideTest, IdTooLarge) {
 }
 
 TEST_F(ResolverOverrideTest, F16_TemporallyBan) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Override(Source{{12, 34}}, "a", ty.f16(), Expr(1_h), Id(1_u));
 

src/tint/resolver/resolver.cc

@@ -143,7 +143,7 @@ bool Resolver::Resolve() {
 
     if (result) {
         // Run the uniformity analysis, which requires a complete semantic module.
-        if (!enabled_extensions_.Contains(ast::Extension::kChromiumDisableUniformityAnalysis)) {
+        if (!enabled_extensions_.Contains(builtin::Extension::kChromiumDisableUniformityAnalysis)) {
             if (!AnalyzeUniformity(builder_, dependencies_)) {
                 return false;
             }

src/tint/resolver/resolver.h

@@ -501,7 +501,7 @@ class Resolver {
     DependencyGraph dependencies_;
     SemHelper sem_;
     Validator validator_;
-    ast::Extensions enabled_extensions_;
+    builtin::Extensions enabled_extensions_;
     utils::Vector<sem::Function*, 8> entry_points_;
     utils::Hashmap<const type::Type*, const Source*, 8> atomic_composite_info_;
     utils::Bitset<0> marked_;

src/tint/resolver/side_effects_test.cc

@@ -15,6 +15,7 @@
 #include "src/tint/resolver/resolver.h"
 
 #include "gtest/gtest.h"
+#include "src/tint/builtin/extension.h"
 #include "src/tint/resolver/resolver_test_helper.h"
 #include "src/tint/sem/index_accessor_expression.h"
 #include "src/tint/sem/member_accessor_expression.h"
@@ -160,7 +161,7 @@ static std::ostream& operator<<(std::ostream& o, const Case& c) {
 using SideEffectsBuiltinTest = resolver::ResolverTestWithParam<Case>;
 
 TEST_P(SideEffectsBuiltinTest, Test) {
-    Enable(ast::Extension::kChromiumExperimentalDp4A);
+    Enable(tint::builtin::Extension::kChromiumExperimentalDp4A);
     auto& c = GetParam();
 
     uint32_t next_binding = 0;

src/tint/resolver/struct_layout_test.cc

@@ -55,7 +55,7 @@ TEST_F(ResolverStructLayoutTest, Scalars) {
 }
 
 TEST_F(ResolverStructLayoutTest, ScalarsWithF16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* s = Structure("S", utils::Vector{
                                  Member("a", ty.f32()),
@@ -134,7 +134,7 @@ TEST_F(ResolverStructLayoutTest, Alias) {
 }
 
 TEST_F(ResolverStructLayoutTest, ImplicitStrideArrayStaticSize) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* s = Structure("S", utils::Vector{
                                  Member("a", ty.array<i32, 3>()),
@@ -174,7 +174,7 @@ TEST_F(ResolverStructLayoutTest, ImplicitStrideArrayStaticSize) {
 }
 
 TEST_F(ResolverStructLayoutTest, ExplicitStrideArrayStaticSize) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* s = Structure("S", utils::Vector{
                                  Member("a", ty.array<i32, 3>(utils::Vector{Stride(8)})),
@@ -335,7 +335,7 @@ TEST_F(ResolverStructLayoutTest, Vector) {
 }
 
 TEST_F(ResolverStructLayoutTest, Matrix) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* s = Structure("S", utils::Vector{
                                  Member("a_1", ty.mat2x2<f32>()),

src/tint/resolver/type_initializer_validation_test.cc

@@ -85,7 +85,7 @@ TEST_P(InferTypeTest_FromInitializerExpression, All) {
     // }
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* initializer_expr = params.create_rhs_ast_value(*this, 0);
 
@@ -186,7 +186,7 @@ TEST_P(InferTypeTest_FromCallExpression, All) {
     // }
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Func("foo", utils::Empty, params.create_rhs_ast_type(*this),
          utils::Vector{Return(Call(params.create_rhs_ast_type(*this)))}, {});
@@ -343,7 +343,7 @@ using ConversionInitializerValidTest = ResolverTestWithParam<Params>;
 TEST_P(ConversionInitializerValidTest, All) {
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     // var a : <lhs_type1> = <lhs_type2>(<rhs_type>(<rhs_value_expr>));
     auto lhs_type1 = params.lhs_type(*this);
@@ -449,7 +449,7 @@ TEST_P(ConversionInitializerInvalidTest, All) {
        << FriendlyName(rhs_type) << "(<rhs value expr>))";
     SCOPED_TRACE(ss.str());
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* a = Var("a", lhs_type1, Call(lhs_type2, Call(rhs_type, rhs_value_expr)));
 
@@ -944,7 +944,7 @@ TEST_F(ResolverTypeInitializerValidationTest, F32_Success) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, F16_Success) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = Call<f16>(Expr(1.5_h));
     WrapInFunction(expr);
@@ -1000,7 +1000,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Convert_i32_to_u32_Success) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Convert_u32_to_f16_Success) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = Call<f16>(123_u);
     WrapInFunction(expr);
@@ -1020,7 +1020,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Convert_u32_to_f16_Success) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Convert_f16_to_f32_Success) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = Call<f32>(123_h);
     WrapInFunction(expr);
@@ -1052,7 +1052,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Vec2F32_Error_ScalarArgumentTypeMi
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Vec2F16_Error_ScalarArgumentTypeMismatch) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec2<f16>(Source{{12, 34}}, 1_h, 2_f));
 
@@ -1175,7 +1175,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Vec2F32_Success_Scalar) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Vec2F16_Success_Scalar) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* tc = vec2<f16>(1_h, 1_h);
     WrapInFunction(tc);
@@ -1309,7 +1309,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Vec3F32_Error_ScalarArgumentTypeMi
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Vec3F16_Error_ScalarArgumentTypeMismatch) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(Source{{12, 34}}, 1_h, 2_h, 3_f));
 
@@ -1451,7 +1451,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Vec3F32_Success_Scalar) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Vec3F16_Success_Scalar) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* tc = vec3<f16>(1_h, 1_h, 1_h);
     WrapInFunction(tc);
@@ -1632,7 +1632,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Vec4F32_Error_ScalarArgumentTypeMi
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Vec4F16_Error_ScalarArgumentTypeMismatch) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec4<f16>(Source{{12, 34}}, 1_h, 1_h, 1_f, 1_h));
 
@@ -1799,7 +1799,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Vec4F32_Success_Scalar) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, Vec4F16_Success_Scalar) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* tc = vec4<f16>(1_h, 1_h, 1_h, 1_h);
     WrapInFunction(tc);
@@ -2035,7 +2035,7 @@ TEST_F(ResolverTypeInitializerValidationTest, Vector_ArgumentElementTypeAlias_Su
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec2ElementTypeFromScalars) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec2_bool = vec2<Infer>(true, false);
     auto* vec2_i32 = vec2<Infer>(1_i, 2_i);
@@ -2064,7 +2064,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec2ElementTypeFromScalars) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec2ElementTypeFromVec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec2_bool = vec2<Infer>(vec2<bool>(true, false));
     auto* vec2_i32 = vec2<Infer>(vec2<i32>(1_i, 2_i));
@@ -2093,7 +2093,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec2ElementTypeFromVec2) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec3ElementTypeFromScalars) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec3_bool = vec3<Infer>(Expr(true), Expr(false), Expr(true));
     auto* vec3_i32 = vec3<Infer>(Expr(1_i), Expr(2_i), Expr(3_i));
@@ -2122,7 +2122,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec3ElementTypeFromScalars) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec3ElementTypeFromVec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec3_bool = vec3<Infer>(vec3<bool>(true, false, true));
     auto* vec3_i32 = vec3<Infer>(vec3<i32>(1_i, 2_i, 3_i));
@@ -2151,7 +2151,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec3ElementTypeFromVec3) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec3ElementTypeFromScalarAndVec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec3_bool = vec3<Infer>(Expr(true), vec2<bool>(false, true));
     auto* vec3_i32 = vec3<Infer>(Expr(1_i), vec2<i32>(2_i, 3_i));
@@ -2180,7 +2180,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec3ElementTypeFromScalarAndV
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec4ElementTypeFromScalars) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec4_bool = vec4<Infer>(Expr(true), Expr(false), Expr(true), Expr(false));
     auto* vec4_i32 = vec4<Infer>(Expr(1_i), Expr(2_i), Expr(3_i), Expr(4_i));
@@ -2209,7 +2209,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec4ElementTypeFromScalars) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec4ElementTypeFromVec4) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec4_bool = vec4<Infer>(vec4<bool>(true, false, true, false));
     auto* vec4_i32 = vec4<Infer>(vec4<i32>(1_i, 2_i, 3_i, 4_i));
@@ -2238,7 +2238,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec4ElementTypeFromVec4) {
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec4ElementTypeFromScalarAndVec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec4_bool = vec4<Infer>(Expr(true), vec3<bool>(false, true, false));
     auto* vec4_i32 = vec4<Infer>(Expr(1_i), vec3<i32>(2_i, 3_i, 4_i));
@@ -2267,7 +2267,7 @@ TEST_F(ResolverTypeInitializerValidationTest, InferVec4ElementTypeFromScalarAndV
 }
 
 TEST_F(ResolverTypeInitializerValidationTest, InferVec4ElementTypeFromVec2AndVec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec4_bool = vec4<Infer>(vec2<bool>(true, false), vec2<bool>(true, false));
     auto* vec4_i32 = vec4<Infer>(vec2<i32>(1_i, 2_i), vec2<i32>(3_i, 4_i));
@@ -2406,7 +2406,7 @@ TEST_P(MatrixInitializerTest, ColumnInitializer_Error_TooFewArguments) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     const std::string element_type_name = param.get_element_type_name();
     std::stringstream args_tys;
@@ -2435,7 +2435,7 @@ TEST_P(MatrixInitializerTest, ElementInitializer_Error_TooFewArguments) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     const std::string element_type_name = param.get_element_type_name();
     std::stringstream args_tys;
@@ -2463,7 +2463,7 @@ TEST_P(MatrixInitializerTest, ColumnInitializer_Error_TooManyArguments) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     const std::string element_type_name = param.get_element_type_name();
     std::stringstream args_tys;
@@ -2492,7 +2492,7 @@ TEST_P(MatrixInitializerTest, ElementInitializer_Error_TooManyArguments) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     const std::string element_type_name = param.get_element_type_name();
     std::stringstream args_tys;
@@ -2520,7 +2520,7 @@ TEST_P(MatrixInitializerTest, ColumnInitializer_Error_InvalidArgumentType) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     std::stringstream args_tys;
     utils::Vector<const ast::Expression*, 8> args;
@@ -2548,7 +2548,7 @@ TEST_P(MatrixInitializerTest, ElementInitializer_Error_InvalidArgumentType) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     std::stringstream args_tys;
     utils::Vector<const ast::Expression*, 8> args;
@@ -2580,7 +2580,7 @@ TEST_P(MatrixInitializerTest, ColumnInitializer_Error_TooFewRowsInVectorArgument
         return;
     }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     const std::string element_type_name = param.get_element_type_name();
     std::stringstream args_tys;
@@ -2618,7 +2618,7 @@ TEST_P(MatrixInitializerTest, ColumnInitializer_Error_TooManyRowsInVectorArgumen
         return;
     }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     const std::string element_type_name = param.get_element_type_name();
     std::stringstream args_tys;
@@ -2650,7 +2650,7 @@ TEST_P(MatrixInitializerTest, ZeroValue_Success) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     ast::Type matrix_type = param.create_mat_ast_type(*this);
     auto* tc = Call(Source{{12, 40}}, matrix_type);
@@ -2665,7 +2665,7 @@ TEST_P(MatrixInitializerTest, WithColumns_Success) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     utils::Vector<const ast::Expression*, 4> args;
     for (uint32_t i = 0; i < param.columns; i++) {
@@ -2686,7 +2686,7 @@ TEST_P(MatrixInitializerTest, WithElements_Success) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     utils::Vector<const ast::Expression*, 16> args;
     for (uint32_t i = 0; i < param.columns * param.rows; i++) {
@@ -2706,7 +2706,7 @@ TEST_P(MatrixInitializerTest, ElementTypeAlias_Error) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* elem_type_alias = Alias("ElemType", param.create_element_ast_type(*this));
 
@@ -2736,7 +2736,7 @@ TEST_P(MatrixInitializerTest, ElementTypeAlias_Success) {
 
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* elem_type_alias = Alias("ElemType", param.create_element_ast_type(*this));
 
@@ -2767,7 +2767,7 @@ TEST_F(ResolverTypeInitializerValidationTest, MatrixInitializer_ArgumentTypeAlia
 TEST_P(MatrixInitializerTest, ArgumentTypeAlias_Success) {
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     ast::Type matrix_type = param.create_mat_ast_type(*this);
     ast::Type vec_type = param.create_column_ast_type(*this);
@@ -2787,7 +2787,7 @@ TEST_P(MatrixInitializerTest, ArgumentTypeAlias_Success) {
 TEST_P(MatrixInitializerTest, ArgumentElementTypeAlias_Error) {
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     ast::Type matrix_type = param.create_mat_ast_type(*this);
     auto* u32_type_alias = Alias("UnsignedInt", ty.u32());
@@ -2814,7 +2814,7 @@ TEST_P(MatrixInitializerTest, ArgumentElementTypeAlias_Error) {
 TEST_P(MatrixInitializerTest, ArgumentElementTypeAlias_Success) {
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* elem_type_alias = Alias("ElemType", param.create_element_ast_type(*this));
 
@@ -2834,7 +2834,7 @@ TEST_P(MatrixInitializerTest, ArgumentElementTypeAlias_Success) {
 TEST_P(MatrixInitializerTest, InferElementTypeFromVectors) {
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     utils::Vector<const ast::Expression*, 8> args;
     for (uint32_t i = 0; i < param.columns; i++) {
@@ -2851,7 +2851,7 @@ TEST_P(MatrixInitializerTest, InferElementTypeFromVectors) {
 TEST_P(MatrixInitializerTest, InferElementTypeFromScalars) {
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     utils::Vector<const ast::Expression*, 8> args;
     for (uint32_t i = 0; i < param.rows * param.columns; i++) {
@@ -2867,7 +2867,7 @@ TEST_P(MatrixInitializerTest, InferElementTypeFromScalars) {
 TEST_P(MatrixInitializerTest, CannotInferElementTypeFromVectors_Mismatch) {
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     std::stringstream err;
     err << "12:34 error: no matching initializer for mat" << param.columns << "x" << param.rows
@@ -2898,7 +2898,7 @@ TEST_P(MatrixInitializerTest, CannotInferElementTypeFromVectors_Mismatch) {
 TEST_P(MatrixInitializerTest, CannotInferElementTypeFromScalars_Mismatch) {
     const auto param = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     std::stringstream err;
     err << "12:34 error: no matching initializer for mat" << param.columns << "x" << param.rows
@@ -2988,7 +2988,7 @@ TEST_P(StructInitializerInputsTest, TooFew) {
     auto& str_params = std::get<0>(param);
     uint32_t N = std::get<1>(param);
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     utils::Vector<const ast::StructMember*, 16> members;
     utils::Vector<const ast::Expression*, 16> values;
@@ -3013,7 +3013,7 @@ TEST_P(StructInitializerInputsTest, TooMany) {
     auto& str_params = std::get<0>(param);
     uint32_t N = std::get<1>(param);
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     utils::Vector<const ast::StructMember*, 16> members;
     utils::Vector<const ast::Expression*, 8> values;
@@ -3046,7 +3046,7 @@ TEST_P(StructInitializerTypeTest, AllTypes) {
     auto& ctor_params = std::get<1>(param);
     uint32_t N = std::get<2>(param);
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     if (str_params.ast == ctor_params.ast) {
         return;

src/tint/resolver/type_validation_test.cc

@@ -1005,7 +1005,7 @@ static constexpr TypeParams type_cases[] = {
 using SampledTextureTypeTest = ResolverTestWithParam<TypeParams>;
 TEST_P(SampledTextureTypeTest, All) {
     auto& params = GetParam();
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     GlobalVar(
         "a",
         ty.sampled_texture(Source{{12, 34}}, type::TextureDimension::k2d, params.type_func(*this)),
@@ -1025,7 +1025,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverTypeValidationTest,
 using MultisampledTextureTypeTest = ResolverTestWithParam<TypeParams>;
 TEST_P(MultisampledTextureTypeTest, All) {
     auto& params = GetParam();
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     GlobalVar("a",
               ty.multisampled_texture(Source{{12, 34}}, type::TextureDimension::k2d,
                                       params.type_func(*this)),
@@ -1231,7 +1231,7 @@ TEST_P(ValidMatrixTypes, Okay) {
     // var a : matNxM<EL_TY>;
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     ast::Type el_ty = params.elem_ty(*this);
 
@@ -1271,7 +1271,7 @@ TEST_P(InvalidMatrixElementTypes, InvalidElementType) {
     // var a : matNxM<EL_TY>;
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     ast::Type el_ty = params.elem_ty(*this);
 
@@ -1316,7 +1316,7 @@ TEST_P(ValidVectorTypes, Okay) {
     // var a : vecN<EL_TY>;
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.vec(params.elem_ty(*this), params.width), type::AddressSpace::kPrivate);
     EXPECT_TRUE(r()->Resolve()) << r()->error();
@@ -1350,7 +1350,7 @@ TEST_P(InvalidVectorElementTypes, InvalidElementType) {
     // var a : vecN<EL_TY>;
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.vec(Source{{12, 34}}, params.elem_ty(*this), params.width),
               type::AddressSpace::kPrivate);
@@ -1389,7 +1389,7 @@ TEST_P(BuiltinTypeAliasTest, CheckEquivalent) {
     // explicit = aliased;
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Var("aliased", ty(params.alias))),
                    Decl(Var("explicit", params.type(*this))),  //
@@ -1401,7 +1401,7 @@ TEST_P(BuiltinTypeAliasTest, Construct) {
     // var v : vecN<T> = vecTN();
     auto& params = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Var("v", params.type(*this), Call(params.alias))));
     EXPECT_TRUE(r()->Resolve()) << r()->error();
@@ -1449,7 +1449,7 @@ TEST_P(ResolverUntemplatedTypeUsedWithTemplateArgs, Builtin_UseWithTemplateArgs)
     // enable f16;
     // var<private> v : f32<true>;
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     GlobalVar("v", type::AddressSpace::kPrivate, ty(Source{{12, 34}}, GetParam(), true));
 
     EXPECT_FALSE(r()->Resolve());
@@ -1462,7 +1462,7 @@ TEST_P(ResolverUntemplatedTypeUsedWithTemplateArgs, BuiltinAlias_UseWithTemplate
     // alias A = f32;
     // var<private> v : A<true>;
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
     Alias(Source{{56, 78}}, "A", ty(GetParam()));
     GlobalVar("v", type::AddressSpace::kPrivate, ty(Source{{12, 34}}, "A", true));
 

src/tint/resolver/validator.cc

@@ -149,7 +149,7 @@ void TraverseCallChain(diag::List& diagnostics,
 Validator::Validator(
     ProgramBuilder* builder,
     SemHelper& sem,
-    const ast::Extensions& enabled_extensions,
+    const builtin::Extensions& enabled_extensions,
     const utils::Hashmap<const type::Type*, const Source*, 8>& atomic_composite_info,
     utils::Hashset<TypeAndAddressSpace, 8>& valid_type_storage_layouts)
     : symbols_(builder->Symbols()),
@@ -829,7 +829,7 @@ bool Validator::Parameter(const ast::Function* func, const sem::Variable* var) c
                 case type::AddressSpace::kUniform:
                 case type::AddressSpace::kWorkgroup:
                     ok = enabled_extensions_.Contains(
-                        ast::Extension::kChromiumExperimentalFullPtrParameters);
+                        builtin::Extension::kChromiumExperimentalFullPtrParameters);
                     break;
                 default:
                     break;
@@ -1653,7 +1653,7 @@ bool Validator::RequiredExtensionForBuiltinFunction(const sem::Call* call) const
     }
 
     const auto extension = builtin->RequiredExtension();
-    if (extension == ast::Extension::kUndefined) {
+    if (extension == builtin::Extension::kUndefined) {
         return true;
     }
 
@@ -1669,7 +1669,7 @@ bool Validator::RequiredExtensionForBuiltinFunction(const sem::Call* call) const
 
 bool Validator::CheckF16Enabled(const Source& source) const {
     // Validate if f16 type is allowed.
-    if (!enabled_extensions_.Contains(ast::Extension::kF16)) {
+    if (!enabled_extensions_.Contains(builtin::Extension::kF16)) {
         AddError("f16 type used without 'f16' extension enabled", source);
         return false;
     }
@@ -1719,7 +1719,8 @@ bool Validator::FunctionCall(const sem::Call* call, sem::Statement* current_stat
         }
 
         if (param_type->Is<type::Pointer>() &&
-            !enabled_extensions_.Contains(ast::Extension::kChromiumExperimentalFullPtrParameters)) {
+            !enabled_extensions_.Contains(
+                builtin::Extension::kChromiumExperimentalFullPtrParameters)) {
             // https://gpuweb.github.io/gpuweb/wgsl/#function-restriction
             // Each argument of pointer type to a user-defined function must have the same memory
             // view as its root identifier.
@@ -2512,7 +2513,7 @@ bool Validator::CheckTypeAccessAddressSpace(
     }
 
     if (address_space == type::AddressSpace::kPushConstant &&
-        !enabled_extensions_.Contains(ast::Extension::kChromiumExperimentalPushConstant) &&
+        !enabled_extensions_.Contains(builtin::Extension::kChromiumExperimentalPushConstant) &&
         IsValidationEnabled(attributes, ast::DisabledValidation::kIgnoreAddressSpace)) {
         AddError(
             "use of variable address space 'push_constant' requires enabling extension "

src/tint/resolver/validator.h

@@ -102,7 +102,7 @@ class Validator {
     /// @param valid_type_storage_layouts a set of validated type layouts by address space
     Validator(ProgramBuilder* builder,
               SemHelper& helper,
-              const ast::Extensions& enabled_extensions,
+              const builtin::Extensions& enabled_extensions,
               const utils::Hashmap<const type::Type*, const Source*, 8>& atomic_composite_info,
               utils::Hashset<TypeAndAddressSpace, 8>& valid_type_storage_layouts);
     ~Validator();
@@ -550,7 +550,7 @@ class Validator {
     diag::List& diagnostics_;
     SemHelper& sem_;
     DiagnosticFilterStack diagnostic_filters_;
-    const ast::Extensions& enabled_extensions_;
+    const builtin::Extensions& enabled_extensions_;
     const utils::Hashmap<const type::Type*, const Source*, 8>& atomic_composite_info_;
     utils::Hashset<TypeAndAddressSpace, 8>& valid_type_storage_layouts_;
 };

src/tint/resolver/variable_test.cc

@@ -41,7 +41,7 @@ TEST_F(ResolverVariableTest, LocalVar_NoInitializer) {
     //   var a : A;
     // }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* S = Structure("S", utils::Vector{Member("i", ty.i32())});
     auto* A = Alias("A", ty.Of(S));
@@ -106,7 +106,7 @@ TEST_F(ResolverVariableTest, LocalVar_WithInitializer) {
     //   var a : A = A(1);
     // }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* S = Structure("S", utils::Vector{Member("i", ty.i32())});
     auto* A = Alias("A", ty.Of(S));
@@ -399,7 +399,7 @@ TEST_F(ResolverVariableTest, LocalLet) {
     //   let p : pointer<function, i32> = &v;
     // }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* S = Structure("S", utils::Vector{Member("i", ty.i32())});
     auto* A = Alias("A", ty.Of(S));

src/tint/resolver/variable_validation_test.cc

@@ -488,7 +488,7 @@ TEST_F(ResolverVariableValidationTest, ConstInitWithOverrideExpr) {
 TEST_F(ResolverVariableValidationTest, GlobalVariable_PushConstantWithInitializer) {
     // enable chromium_experimental_push_constant;
     // var<push_constant> a : u32 = 0u;
-    Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    Enable(builtin::Extension::kChromiumExperimentalPushConstant);
     GlobalVar(Source{{1u, 2u}}, "a", ty.u32(), type::AddressSpace::kPushConstant,
               Expr(Source{{3u, 4u}}, u32(0)));
 

src/tint/sem/builtin.cc

@@ -179,11 +179,11 @@ bool Builtin::HasSideEffects() const {
     return false;
 }
 
-ast::Extension Builtin::RequiredExtension() const {
+builtin::Extension Builtin::RequiredExtension() const {
     if (IsDP4a()) {
-        return ast::Extension::kChromiumExperimentalDp4A;
+        return builtin::Extension::kChromiumExperimentalDp4A;
     }
-    return ast::Extension::kUndefined;
+    return builtin::Extension::kUndefined;
 }
 
 }  // namespace tint::sem

src/tint/sem/builtin.h

@@ -18,7 +18,7 @@
 #include <string>
 #include <vector>
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
 #include "src/tint/sem/builtin_type.h"
 #include "src/tint/sem/call_target.h"
 #include "src/tint/sem/pipeline_stage_set.h"
@@ -147,8 +147,8 @@ class Builtin final : public Castable<Builtin, CallTarget> {
     bool HasSideEffects() const;
 
     /// @returns the required extension of this builtin function. Returns
-    /// ast::Extension::kNone if no extension is required.
-    ast::Extension RequiredExtension() const;
+    /// builtin::Extension::kNone if no extension is required.
+    builtin::Extension RequiredExtension() const;
 
   private:
     const BuiltinType type_;

src/tint/sem/module.cc

@@ -21,7 +21,7 @@ TINT_INSTANTIATE_TYPEINFO(tint::sem::Module);
 
 namespace tint::sem {
 
-Module::Module(utils::VectorRef<const ast::Node*> dep_ordered_decls, ast::Extensions extensions)
+Module::Module(utils::VectorRef<const ast::Node*> dep_ordered_decls, builtin::Extensions extensions)
     : dep_ordered_decls_(std::move(dep_ordered_decls)), extensions_(std::move(extensions)) {}
 
 Module::~Module() = default;

src/tint/sem/module.h

@@ -16,7 +16,7 @@
 #define SRC_TINT_SEM_MODULE_H_
 
 #include "src/tint/ast/diagnostic_control.h"
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
 #include "src/tint/sem/node.h"
 #include "src/tint/utils/vector.h"
 
@@ -34,7 +34,7 @@ class Module final : public Castable<Module, Node> {
     /// Constructor
     /// @param dep_ordered_decls the dependency-ordered module-scope declarations
     /// @param extensions the list of enabled extensions in the module
-    Module(utils::VectorRef<const ast::Node*> dep_ordered_decls, ast::Extensions extensions);
+    Module(utils::VectorRef<const ast::Node*> dep_ordered_decls, builtin::Extensions extensions);
 
     /// Destructor
     ~Module() override;
@@ -45,7 +45,7 @@ class Module final : public Castable<Module, Node> {
     }
 
     /// @returns the list of enabled extensions in the module
-    const ast::Extensions& Extensions() const { return extensions_; }
+    const builtin::Extensions& Extensions() const { return extensions_; }
 
     /// Modifies the severity of a specific diagnostic rule for this module.
     /// @param rule the diagnostic rule
@@ -61,7 +61,7 @@ class Module final : public Castable<Module, Node> {
 
   private:
     const utils::Vector<const ast::Node*, 64> dep_ordered_decls_;
-    ast::Extensions extensions_;
+    builtin::Extensions extensions_;
     ast::DiagnosticRuleSeverities diagnostic_severities_;
 };
 

src/tint/transform/builtin_polyfill.cc

@@ -45,7 +45,7 @@ struct BuiltinPolyfill::State {
     State(CloneContext& c, Builtins p) : ctx(c), polyfill(p) {
         has_full_ptr_params = false;
         for (auto* enable : c.src->AST().Enables()) {
-            if (enable->extension == ast::Extension::kChromiumExperimentalFullPtrParameters) {
+            if (enable->extension == builtin::Extension::kChromiumExperimentalFullPtrParameters) {
                 has_full_ptr_params = true;
             }
         }
@@ -673,7 +673,7 @@ struct BuiltinPolyfill::State {
     /// @return the polyfill function name
     Symbol workgroupUniformLoad(const type::Type* type) {
         if (!has_full_ptr_params) {
-            b.Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+            b.Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
             has_full_ptr_params = true;
         }
         auto name = b.Symbols().New("tint_workgroupUniformLoad");

src/tint/transform/clamp_frag_depth.cc

@@ -117,7 +117,7 @@ Transform::ApplyResult ClampFragDepth::Apply(const Program* src, const DataMap&,
     //   fn clamp_frag_depth(v : f32) -> f32 {
     //       return clamp(v, frag_depth_clamp_args.min, frag_depth_clamp_args.max);
     //   }
-    b.Enable(ast::Extension::kChromiumExperimentalPushConstant);
+    b.Enable(builtin::Extension::kChromiumExperimentalPushConstant);
 
     b.Structure(b.Symbols().New("FragDepthClampArgs"),
                 utils::Vector{b.Member("min", b.ty.f32()), b.Member("max", b.ty.f32())});

src/tint/transform/direct_variable_access.cc

@@ -203,7 +203,7 @@ struct DirectVariableAccess::State {
     /// @returns the ApplyResult
     ApplyResult Run() {
         if (!ctx.src->Sem().Module()->Extensions().Contains(
-                ast::Extension::kChromiumExperimentalFullPtrParameters)) {
+                builtin::Extension::kChromiumExperimentalFullPtrParameters)) {
             // If the 'chromium_experimental_full_ptr_parameters' extension is not enabled, then
             // there's nothing for this transform to do.
             return SkipTransform;

src/tint/transform/disable_uniformity_analysis.cc

@@ -31,13 +31,13 @@ Transform::ApplyResult DisableUniformityAnalysis::Apply(const Program* src,
                                                         const DataMap&,
                                                         DataMap&) const {
     if (src->Sem().Module()->Extensions().Contains(
-            ast::Extension::kChromiumDisableUniformityAnalysis)) {
+            builtin::Extension::kChromiumDisableUniformityAnalysis)) {
         return SkipTransform;
     }
 
     ProgramBuilder b;
     CloneContext ctx{&b, src, /* auto_clone_symbols */ true};
-    b.Enable(ast::Extension::kChromiumDisableUniformityAnalysis);
+    b.Enable(builtin::Extension::kChromiumDisableUniformityAnalysis);
 
     ctx.Clone();
     return Program(std::move(b));

src/tint/transform/preserve_padding.cc

@@ -66,7 +66,7 @@ struct PreservePadding::State {
                 [&](const ast::Enable* enable) {
                     // Check if the full pointer parameters extension is already enabled.
                     if (enable->extension ==
-                        ast::Extension::kChromiumExperimentalFullPtrParameters) {
+                        builtin::Extension::kChromiumExperimentalFullPtrParameters) {
                         ext_enabled = true;
                     }
                 });
@@ -197,7 +197,7 @@ struct PreservePadding::State {
     /// Enable the full pointer parameters extension, if we have not already done so.
     void EnableExtension() {
         if (!ext_enabled) {
-            b.Enable(ast::Extension::kChromiumExperimentalFullPtrParameters);
+            b.Enable(builtin::Extension::kChromiumExperimentalFullPtrParameters);
             ext_enabled = true;
         }
     }

src/tint/writer/check_supported_extensions.cc

@@ -26,8 +26,8 @@ namespace tint::writer {
 bool CheckSupportedExtensions(std::string_view writer_name,
                               const ast::Module& module,
                               diag::List& diags,
-                              utils::VectorRef<ast::Extension> supported) {
-    utils::Hashset<ast::Extension, 32> set;
+                              utils::VectorRef<builtin::Extension> supported) {
+    utils::Hashset<builtin::Extension, 32> set;
     for (auto ext : supported) {
         set.Add(ext);
     }

src/tint/writer/check_supported_extensions.h

@@ -15,7 +15,7 @@
 #ifndef SRC_TINT_WRITER_CHECK_SUPPORTED_EXTENSIONS_H_
 #define SRC_TINT_WRITER_CHECK_SUPPORTED_EXTENSIONS_H_
 
-#include "src/tint/ast/extension.h"
+#include "src/tint/builtin/extension.h"
 #include "src/tint/utils/vector.h"
 
 namespace tint::ast {
@@ -36,7 +36,7 @@ namespace tint::writer {
 bool CheckSupportedExtensions(std::string_view writer_name,
                               const ast::Module& module,
                               diag::List& diags,
-                              utils::VectorRef<ast::Extension> supported);
+                              utils::VectorRef<builtin::Extension> supported);
 
 }  // namespace tint::writer
 

src/tint/writer/check_supported_extensions_test.cc

@@ -24,21 +24,21 @@ namespace {
 class CheckSupportedExtensionsTest : public ::testing::Test, public ProgramBuilder {};
 
 TEST_F(CheckSupportedExtensionsTest, Supported) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     ASSERT_TRUE(CheckSupportedExtensions("writer", AST(), Diagnostics(),
                                          utils::Vector{
-                                             ast::Extension::kF16,
-                                             ast::Extension::kChromiumExperimentalDp4A,
+                                             builtin::Extension::kF16,
+                                             builtin::Extension::kChromiumExperimentalDp4A,
                                          }));
 }
 
 TEST_F(CheckSupportedExtensionsTest, Unsupported) {
-    Enable(Source{{12, 34}}, ast::Extension::kF16);
+    Enable(Source{{12, 34}}, builtin::Extension::kF16);
 
     ASSERT_FALSE(CheckSupportedExtensions("writer", AST(), Diagnostics(),
                                           utils::Vector{
-                                              ast::Extension::kChromiumExperimentalDp4A,
+                                              builtin::Extension::kChromiumExperimentalDp4A,
                                           }));
     EXPECT_EQ(Diagnostics().str(), "12:34 error: writer backend does not support extension 'f16'");
 }

src/tint/writer/glsl/generator_impl.cc

@@ -326,7 +326,7 @@ bool GeneratorImpl::Generate() {
 bool GeneratorImpl::RecordExtension(const ast::Enable* ext) {
     // Deal with extension node here, recording it within the generator for later emition.
 
-    if (ext->extension == ast::Extension::kF16) {
+    if (ext->extension == builtin::Extension::kF16) {
         requires_f16_extension_ = true;
     }
 

src/tint/writer/glsl/generator_impl_binary_test.cc

@@ -69,7 +69,7 @@ TEST_P(GlslBinaryTest, Emit_f16) {
         return;
     }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("left", ty.f16(), type::AddressSpace::kPrivate);
     GlobalVar("right", ty.f16(), type::AddressSpace::kPrivate);
@@ -167,7 +167,7 @@ TEST_F(GlslGeneratorImplTest_Binary, Multiply_VectorScalar_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, Multiply_VectorScalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", vec3<f16>(1_h, 1_h, 1_h), type::AddressSpace::kPrivate);
     auto* lhs = Expr("a");
@@ -201,7 +201,7 @@ TEST_F(GlslGeneratorImplTest_Binary, Multiply_ScalarVector_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, Multiply_ScalarVector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", vec3<f16>(1_h, 1_h, 1_h), type::AddressSpace::kPrivate);
     auto* lhs = Expr(1_h);
@@ -234,7 +234,7 @@ TEST_F(GlslGeneratorImplTest_Binary, Multiply_MatrixScalar_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, Multiply_MatrixScalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = Expr("mat");
@@ -266,7 +266,7 @@ TEST_F(GlslGeneratorImplTest_Binary, Multiply_ScalarMatrix_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, Multiply_ScalarMatrix_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = Expr(1_h);
@@ -298,7 +298,7 @@ TEST_F(GlslGeneratorImplTest_Binary, Multiply_MatrixVector_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, Multiply_MatrixVector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = Expr("mat");
@@ -330,7 +330,7 @@ TEST_F(GlslGeneratorImplTest_Binary, Multiply_VectorMatrix_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, Multiply_VectorMatrix_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = vec3<f16>(1_h, 1_h, 1_h);
@@ -361,7 +361,7 @@ TEST_F(GlslGeneratorImplTest_Binary, Multiply_MatrixMatrix_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, Multiply_MatrixMatrix_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("lhs", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     GlobalVar("rhs", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
@@ -391,7 +391,7 @@ TEST_F(GlslGeneratorImplTest_Binary, ModF32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, ModF16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.f16(), type::AddressSpace::kPrivate);
     GlobalVar("b", ty.f16(), type::AddressSpace::kPrivate);
@@ -421,7 +421,7 @@ TEST_F(GlslGeneratorImplTest_Binary, ModVec3F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, ModVec3F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.vec3<f16>(), type::AddressSpace::kPrivate);
     GlobalVar("b", ty.vec3<f16>(), type::AddressSpace::kPrivate);
@@ -451,7 +451,7 @@ TEST_F(GlslGeneratorImplTest_Binary, ModVec3F32ScalarF32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, ModVec3F16ScalarF16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.vec3<f16>(), type::AddressSpace::kPrivate);
     GlobalVar("b", ty.f16(), type::AddressSpace::kPrivate);
@@ -481,7 +481,7 @@ TEST_F(GlslGeneratorImplTest_Binary, ModScalarF32Vec3F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, ModScalarF16Vec3F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.f16(), type::AddressSpace::kPrivate);
     GlobalVar("b", ty.vec3<f16>(), type::AddressSpace::kPrivate);
@@ -539,7 +539,7 @@ void test_function() {
 }
 
 TEST_F(GlslGeneratorImplTest_Binary, ModMixedVec3ScalarF16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.vec3<f16>(), type::AddressSpace::kPrivate);
     GlobalVar("b", ty.f16(), type::AddressSpace::kPrivate);

src/tint/writer/glsl/generator_impl_builtin_test.cc

@@ -196,7 +196,7 @@ TEST_P(GlslBuiltinTest, Emit) {
     auto param = GetParam();
 
     if (param.type == CallParamType::kF16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
 
         GlobalVar("h2", ty.vec2<f16>(), type::AddressSpace::kPrivate);
         GlobalVar("h3", ty.vec3<f16>(), type::AddressSpace::kPrivate);
@@ -399,7 +399,7 @@ TEST_F(GlslGeneratorImplTest_Builtin, FMA_f32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, FMA_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("a", ty.vec3<f16>(), type::AddressSpace::kPrivate);
     GlobalVar("b", ty.vec3<f16>(), type::AddressSpace::kPrivate);
@@ -451,7 +451,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Runtime_Modf_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("f", Expr(1.5_h))),  //
                    Decl(Let("v", Call("modf", "f"))));
@@ -522,7 +522,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Runtime_Modf_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("f", vec3<f16>(1.5_h, 2.5_h, 3.5_h))),  //
                    Decl(Let("v", Call("modf", "f"))));
@@ -585,7 +585,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Const_Modf_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("modf", 1.5_h))));
 
@@ -640,7 +640,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Const_Modf_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("modf", vec3<f16>(1.5_h, 2.5_h, 3.5_h)))));
 
@@ -703,7 +703,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Runtime_Frexp_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Var("f", Expr(1_h)),  //
                    Var("v", Call("frexp", "f")));
@@ -774,7 +774,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Runtime_Frexp_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Var("f", Expr(vec3<f16>())),  //
                    Var("v", Call("frexp", "f")));
@@ -837,7 +837,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Const_Frexp_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("frexp", 1_h))));
 
@@ -892,7 +892,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Const_Frexp_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("frexp", vec3<f16>()))));
 
@@ -977,7 +977,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Degrees_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.f16());
     auto* call = Call("degrees", val);
@@ -1008,7 +1008,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Degrees_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.vec3<f16>());
     auto* call = Call("degrees", val);
@@ -1095,7 +1095,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Radians_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.f16());
     auto* call = Call("radians", val);
@@ -1126,7 +1126,7 @@ void main() {
 }
 
 TEST_F(GlslGeneratorImplTest_Builtin, Radians_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.vec3<f16>());
     auto* call = Call("radians", val);

src/tint/writer/glsl/generator_impl_initializer_test.cc

@@ -62,7 +62,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Float) {
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     // Use a number close to 1<<16 but whose decimal representation ends in 0.
     WrapInFunction(Expr(f16((1 << 15) - 8)));
@@ -83,7 +83,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Float) {
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Call<f16>(-1.2e-3_h));
 
@@ -130,7 +130,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(1_h, 2_h, 3_h));
 
@@ -150,7 +150,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_Empty_F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_Empty_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>());
 
@@ -170,7 +170,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_F16_Literal) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(2_h));
 
@@ -193,7 +193,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_F16_Var) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("v", Expr(2_h));
     auto* cast = vec3<f16>(var);
@@ -244,7 +244,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(mat2x3<f16>(vec3<f16>(1_h, 2_h, 3_h), vec3<f16>(3_h, 4_h, 5_h)));
 
@@ -290,7 +290,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Complex_F16)
     //     vec4<f16>(7.0h),
     //     vec4<f16>(vec4<f16>(42.0h, 21.0h, 6.0h, -5.0h)),
     //   );
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vector_literal =
         vec4<f16>(Expr(f16(2.0)), Expr(f16(3.0)), Expr(f16(4.0)), Expr(f16(8.0)));
@@ -324,7 +324,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Empty_F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Empty_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(mat2x3<f16>());
 
@@ -360,7 +360,7 @@ TEST_F(GlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Identity_F16)
     //     var m_2: mat4x4<f16> = mat4x4<f16>(m_1);
     // }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* m_1 = Var("m_1", ty.mat4x4(ty.f16()), mat4x4<f16>());
     auto* m_2 = Var("m_2", ty.mat4x4(ty.f16()), mat4x4<f16>(m_1));

src/tint/writer/glsl/generator_impl_module_constant_test.cc

@@ -133,7 +133,7 @@ void f() {
 }
 
 TEST_F(GlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", Expr(1_h));
     Func("f", utils::Empty, ty.void_(),
@@ -216,7 +216,7 @@ void f() {
 }
 
 TEST_F(GlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_vec3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", vec3<f16>(1_h, 2_h, 3_h));
     Func("f", utils::Empty, ty.void_(),
@@ -279,7 +279,7 @@ void f() {
 }
 
 TEST_F(GlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_mat2x3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", mat2x3<f16>(1_h, 2_h, 3_h, 4_h, 5_h, 6_h));
     Func("f", utils::Empty, ty.void_(),

src/tint/writer/glsl/generator_impl_type_test.cc

@@ -107,7 +107,7 @@ TEST_F(GlslGeneratorImplTest_Type, EmitType_F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Type, EmitType_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* f16 = create<type::F16>();
 
@@ -144,7 +144,7 @@ TEST_F(GlslGeneratorImplTest_Type, EmitType_Matrix_F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Type, EmitType_Matrix_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* f16 = create<type::F16>();
     auto* vec3 = create<type::Vector>(f16, 3u);
@@ -255,7 +255,7 @@ TEST_F(GlslGeneratorImplTest_Type, EmitType_Vector_F32) {
 }
 
 TEST_F(GlslGeneratorImplTest_Type, EmitType_Vector_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* f16 = create<type::F16>();
     auto* vec3 = create<type::Vector>(f16, 3u);

src/tint/writer/glsl/generator_impl_variable_decl_statement_test.cc

@@ -170,7 +170,7 @@ void f() {
 }
 
 TEST_F(GlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", Expr(1_h));
     Func("f", utils::Empty, ty.void_(),
@@ -257,7 +257,7 @@ void f() {
 }
 
 TEST_F(GlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_vec3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", vec3<f16>(1_h, 2_h, 3_h));
     Func("f", utils::Empty, ty.void_(),
@@ -323,7 +323,7 @@ void f() {
 }
 
 TEST_F(GlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_mat2x3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", mat2x3<f16>(1_h, 2_h, 3_h, 4_h, 5_h, 6_h));
     Func("f", utils::Empty, ty.void_(),
@@ -501,7 +501,7 @@ TEST_F(GlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initialize
 }
 
 TEST_F(GlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initializer_ZeroVec_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.vec3<f16>(), vec3<f16>());
 
@@ -530,7 +530,7 @@ TEST_F(GlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initialize
 }
 
 TEST_F(GlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initializer_ZeroMat_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.mat2x3<f16>(), mat2x3<f16>());
 

src/tint/writer/hlsl/generator_impl.cc

@@ -297,11 +297,11 @@ GeneratorImpl::~GeneratorImpl() = default;
 bool GeneratorImpl::Generate() {
     if (!CheckSupportedExtensions("HLSL", program_->AST(), diagnostics_,
                                   utils::Vector{
-                                      ast::Extension::kChromiumDisableUniformityAnalysis,
-                                      ast::Extension::kChromiumExperimentalDp4A,
-                                      ast::Extension::kChromiumExperimentalFullPtrParameters,
-                                      ast::Extension::kChromiumExperimentalPushConstant,
-                                      ast::Extension::kF16,
+                                      builtin::Extension::kChromiumDisableUniformityAnalysis,
+                                      builtin::Extension::kChromiumExperimentalDp4A,
+                                      builtin::Extension::kChromiumExperimentalFullPtrParameters,
+                                      builtin::Extension::kChromiumExperimentalPushConstant,
+                                      builtin::Extension::kF16,
                                   })) {
         return false;
     }

src/tint/writer/hlsl/generator_impl_binary_test.cc

@@ -80,7 +80,7 @@ TEST_P(HlslBinaryTest, Emit_f16) {
         return;
     }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("left", ty.f16(), type::AddressSpace::kPrivate);
     GlobalVar("right", ty.f16(), type::AddressSpace::kPrivate);
@@ -188,7 +188,7 @@ TEST_F(HlslGeneratorImplTest_Binary, Multiply_VectorScalar_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Binary, Multiply_VectorScalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* lhs = vec3<f16>(1_h, 1_h, 1_h);
     auto* rhs = Expr(1_h);
@@ -220,7 +220,7 @@ TEST_F(HlslGeneratorImplTest_Binary, Multiply_ScalarVector_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Binary, Multiply_ScalarVector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* lhs = Expr(1_h);
     auto* rhs = vec3<f16>(1_h, 1_h, 1_h);
@@ -252,7 +252,7 @@ TEST_F(HlslGeneratorImplTest_Binary, Multiply_MatrixScalar_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Binary, Multiply_MatrixScalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = Expr("mat");
@@ -284,7 +284,7 @@ TEST_F(HlslGeneratorImplTest_Binary, Multiply_ScalarMatrix_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Binary, Multiply_ScalarMatrix_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = Expr(1_h);
@@ -316,7 +316,7 @@ TEST_F(HlslGeneratorImplTest_Binary, Multiply_MatrixVector_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Binary, Multiply_MatrixVector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = Expr("mat");
@@ -348,7 +348,7 @@ TEST_F(HlslGeneratorImplTest_Binary, Multiply_VectorMatrix_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Binary, Multiply_VectorMatrix_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("mat", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* lhs = vec3<f16>(1_h, 1_h, 1_h);
@@ -379,7 +379,7 @@ TEST_F(HlslGeneratorImplTest_Binary, Multiply_MatrixMatrix_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Binary, Multiply_MatrixMatrix_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     GlobalVar("lhs", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     GlobalVar("rhs", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);

src/tint/writer/hlsl/generator_impl_builtin_test.cc

@@ -195,7 +195,7 @@ TEST_P(HlslBuiltinTest, Emit) {
     auto param = GetParam();
 
     if (param.type == CallParamType::kF16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
 
         GlobalVar("h2", ty.vec2<f16>(), type::AddressSpace::kPrivate);
         GlobalVar("h3", ty.vec3<f16>(), type::AddressSpace::kPrivate);
@@ -405,7 +405,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Runtime_Modf_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("f", Expr(1.5_h))),  //
                    Decl(Let("v", Call("modf", "f"))));
@@ -459,7 +459,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Runtime_Modf_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("f", vec3<f16>(1.5_h, 2.5_h, 3.5_h))),  //
                    Decl(Let("v", Call("modf", "f"))));
@@ -505,7 +505,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Const_Modf_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("modf", 1.5_h))));
 
@@ -543,7 +543,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Const_Modf_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("modf", vec3<f16>(1.5_h, 2.5_h, 3.5_h)))));
 
@@ -616,7 +616,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Runtime_Frexp_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Var("f", Expr(1_h)),  //
                    Var("v", Call("frexp", "f")));
@@ -672,7 +672,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Runtime_Frexp_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Var("f", Expr(vec3<f16>())),  //
                    Var("v", Call("frexp", "f")));
@@ -719,7 +719,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Const_Frexp_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("frexp", 1_h))));
 
@@ -757,7 +757,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Const_Frexp_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("frexp", vec3<f16>()))));
 
@@ -845,7 +845,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Degrees_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.f16());
     auto* call = Call("degrees", val);
@@ -868,7 +868,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Degrees_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.vec3<f16>());
     auto* call = Call("degrees", val);
@@ -933,7 +933,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Radians_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.f16());
     auto* call = Call("radians", val);
@@ -956,7 +956,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Radians_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.vec3<f16>());
     auto* call = Call("radians", val);
@@ -1047,7 +1047,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Sign_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.f16());
     auto* call = Call("sign", val);
@@ -1066,7 +1066,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Sign_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.vec3<f16>());
     auto* call = Call("sign", val);
@@ -1351,7 +1351,7 @@ void main() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Dot4I8Packed) {
-    Enable(ast::Extension::kChromiumExperimentalDp4A);
+    Enable(builtin::Extension::kChromiumExperimentalDp4A);
 
     auto* val1 = Var("val1", ty.u32());
     auto* val2 = Var("val2", ty.u32());
@@ -1377,7 +1377,7 @@ void test_function() {
 }
 
 TEST_F(HlslGeneratorImplTest_Builtin, Dot4U8Packed) {
-    Enable(ast::Extension::kChromiumExperimentalDp4A);
+    Enable(builtin::Extension::kChromiumExperimentalDp4A);
 
     auto* val1 = Var("val1", ty.u32());
     auto* val2 = Var("val2", ty.u32());

src/tint/writer/hlsl/generator_impl_initializer_test.cc

@@ -62,7 +62,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Float) {
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     // Use a number close to 1<<16 but whose decimal representation ends in 0.
     WrapInFunction(Expr(f16((1 << 15) - 8)));
@@ -83,7 +83,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Float) {
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Call<f16>(-1.2e-3_h));
 
@@ -130,7 +130,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_F32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(1_h, 2_h, 3_h));
 
@@ -152,7 +152,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_Empty_F32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_Empty_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>());
 
@@ -172,7 +172,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_F16_Literal) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(2_h));
 
@@ -195,7 +195,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Vec_SingleScalar_F16_Var) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("v", Expr(2_h));
     auto* cast = vec3<f16>(var);
@@ -259,7 +259,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_F32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(mat2x3<f16>(vec3<f16>(1_h, 2_h, 3_h), vec3<f16>(3_h, 4_h, 5_h)));
 
@@ -307,7 +307,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Complex_F16)
     //     vec4<f16>(7.0h),
     //     vec4<f16>(vec4<f16>(42.0h, 21.0h, 6.0h, -5.0h)),
     //   );
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vector_literal =
         vec4<f16>(Expr(f16(2.0)), Expr(f16(3.0)), Expr(f16(4.0)), Expr(f16(8.0)));
@@ -344,7 +344,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Empty_F32) {
 }
 
 TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Empty_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(mat2x3<f16>());
 
@@ -380,7 +380,7 @@ TEST_F(HlslGeneratorImplTest_Initializer, EmitInitializer_Type_Mat_Identity_F16)
     //     var m_2: mat4x4<f16> = mat4x4<f16>(m_1);
     // }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* m_1 = Var("m_1", ty.mat4x4(ty.f16()), mat4x4<f16>());
     auto* m_2 = Var("m_2", ty.mat4x4(ty.f16()), mat4x4<f16>(m_1));

src/tint/writer/hlsl/generator_impl_member_accessor_test.cc

@@ -165,7 +165,7 @@ TEST_P(HlslGeneratorImplTest_MemberAccessor_StorageBufferLoad_ConstantOffset, Te
 
     auto p = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     SetupStorageBuffer(utils::Vector{
         Member("a", ty.i32()),
@@ -300,7 +300,7 @@ TEST_P(HlslGeneratorImplTest_MemberAccessor_StorageBufferLoad_DynamicOffset, Tes
 
     auto p = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* inner = Structure("Inner", utils::Vector{
                                          Member("a", ty.i32()),
@@ -439,7 +439,7 @@ TEST_P(HlslGeneratorImplTest_MemberAccessor_UniformBufferLoad_ConstantOffset, Te
 
     auto p = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     SetupUniformBuffer(utils::Vector{
         Member("a", ty.i32()),
@@ -707,7 +707,7 @@ TEST_P(HlslGeneratorImplTest_MemberAccessor_UniformBufferLoad_DynamicOffset, Tes
 
     auto p = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* inner = Structure("Inner", utils::Vector{
                                          Member("a", ty.i32()),
@@ -989,7 +989,7 @@ TEST_P(HlslGeneratorImplTest_MemberAccessor_StorageBufferStore, Test) {
 
     auto p = GetParam();
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     SetupStorageBuffer(utils::Vector{
         Member("a", ty.i32()),
@@ -1192,7 +1192,7 @@ TEST_F(HlslGeneratorImplTest_MemberAccessor, StorageBuffer_Load_Matrix_F16_Singl
     // var<storage> data : Data;
     // data.a[2i][1i];
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     SetupStorageBuffer(utils::Vector{
         Member("z", ty.f16()),
@@ -1258,7 +1258,7 @@ TEST_F(HlslGeneratorImplTest_MemberAccessor, UniformBuffer_Load_Matrix_F16_Singl
     // var<uniform> data : Data;
     // data.a[2i][1i];
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     SetupUniformBuffer(utils::Vector{
         Member("z", ty.f16()),

src/tint/writer/hlsl/generator_impl_module_constant_test.cc

@@ -93,7 +93,7 @@ TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", Expr(1_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(Let("l", Expr(var)))});
@@ -151,7 +151,7 @@ TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_vec3_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_vec3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", vec3<f16>(1_h, 2_h, 3_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(Let("l", Expr(var)))});
@@ -195,7 +195,7 @@ TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_mat2x3_f32) {
 }
 
 TEST_F(HlslGeneratorImplTest_ModuleConstant, Emit_GlobalConst_mat2x3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", mat2x3<f16>(1_h, 2_h, 3_h, 4_h, 5_h, 6_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(Let("l", Expr(var)))});

src/tint/writer/hlsl/generator_impl_test.cc

@@ -29,7 +29,7 @@ TEST_F(HlslGeneratorImplTest, InvalidProgram) {
 }
 
 TEST_F(HlslGeneratorImplTest, UnsupportedExtension) {
-    Enable(Source{{12, 34}}, ast::Extension::kUndefined);
+    Enable(Source{{12, 34}}, builtin::Extension::kUndefined);
 
     GeneratorImpl& gen = Build();
 

src/tint/writer/hlsl/generator_impl_variable_decl_statement_test.cc

@@ -155,7 +155,7 @@ TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_f32)
 }
 
 TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", Expr(1_h));
     Func("f", utils::Empty, ty.void_(),
@@ -229,7 +229,7 @@ TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_vec3
 }
 
 TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_vec3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", vec3<f16>(1_h, 2_h, 3_h));
     Func("f", utils::Empty, ty.void_(),
@@ -285,7 +285,7 @@ TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_mat2
 }
 
 TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Const_mat2x3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", mat2x3<f16>(1_h, 2_h, 3_h, 4_h, 5_h, 6_h));
     Func("f", utils::Empty, ty.void_(),
@@ -383,7 +383,7 @@ TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initialize
 }
 
 TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initializer_ZeroVec_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.vec3<f16>(), vec3<f16>());
 
@@ -412,7 +412,7 @@ TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initialize
 }
 
 TEST_F(HlslGeneratorImplTest_VariableDecl, Emit_VariableDeclStatement_Initializer_ZeroMat_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.mat2x3<f16>(), mat2x3<f16>());
 

src/tint/writer/msl/generator_impl.cc

@@ -270,10 +270,10 @@ GeneratorImpl::~GeneratorImpl() = default;
 bool GeneratorImpl::Generate() {
     if (!CheckSupportedExtensions("MSL", program_->AST(), diagnostics_,
                                   utils::Vector{
-                                      ast::Extension::kChromiumDisableUniformityAnalysis,
-                                      ast::Extension::kChromiumExperimentalFullPtrParameters,
-                                      ast::Extension::kChromiumExperimentalPushConstant,
-                                      ast::Extension::kF16,
+                                      builtin::Extension::kChromiumDisableUniformityAnalysis,
+                                      builtin::Extension::kChromiumExperimentalFullPtrParameters,
+                                      builtin::Extension::kChromiumExperimentalPushConstant,
+                                      builtin::Extension::kF16,
                                   })) {
         return false;
     }

src/tint/writer/msl/generator_impl_binary_test.cc

@@ -155,7 +155,7 @@ TEST_F(MslBinaryTest, ModF32) {
 }
 
 TEST_F(MslBinaryTest, ModF16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* left = Var("left", ty.f16());
     auto* right = Var("right", ty.f16());
@@ -183,7 +183,7 @@ TEST_F(MslBinaryTest, ModVec3F32) {
 }
 
 TEST_F(MslBinaryTest, ModVec3F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* left = Var("left", ty.vec3<f16>());
     auto* right = Var("right", ty.vec3<f16>());

src/tint/writer/msl/generator_impl_builtin_test.cc

@@ -214,7 +214,7 @@ TEST_P(MslBuiltinTest, Emit) {
     auto param = GetParam();
 
     if (param.type == CallParamType::kF16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
 
         GlobalVar("h2", ty.vec2<f16>(), type::AddressSpace::kPrivate);
         GlobalVar("h3", ty.vec3<f16>(), type::AddressSpace::kPrivate);
@@ -436,7 +436,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Runtime_Modf_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("f", Expr(1.5_h))),  //
                    Decl(Let("v", Call("modf", "f"))));
@@ -498,7 +498,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Runtime_Modf_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("f", vec3<f16>(1.5_h, 2.5_h, 3.5_h))),  //
                    Decl(Let("v", Call("modf", "f"))));
@@ -552,7 +552,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Const_Modf_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("modf", 1.5_h))));
 
@@ -598,7 +598,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Const_Modf_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("modf", vec3<f16>(1.5_h, 2.5_h, 3.5_h)))));
 
@@ -652,7 +652,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Runtime_Frexp_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Var("f", Expr(1_h)),  //
                    Var("v", Call("frexp", "f")));
@@ -714,7 +714,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Runtime_Frexp_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Var("f", Expr(vec3<f16>())),  //
                    Var("v", Call("frexp", "f")));
@@ -768,7 +768,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Const_Frexp_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("frexp", 1_h))));
 
@@ -814,7 +814,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Const_Frexp_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Decl(Let("v", Call("frexp", vec3<f16>()))));
 
@@ -888,7 +888,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Degrees_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.f16());
     auto* call = Call("degrees", val);
@@ -915,7 +915,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Degrees_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.vec3<f16>());
     auto* call = Call("degrees", val);
@@ -992,7 +992,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Radians_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.f16());
     auto* call = Call("radians", val);
@@ -1019,7 +1019,7 @@ kernel void test_function() {
 }
 
 TEST_F(MslGeneratorImplTest, Radians_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* val = Var("val", ty.vec3<f16>());
     auto* call = Call("radians", val);

src/tint/writer/msl/generator_impl_initializer_test.cc

@@ -62,7 +62,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Float) {
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     // Use a number close to 1<<16 but whose decimal representation ends in 0.
     WrapInFunction(Expr(f16((1 << 15) - 8)));
@@ -83,7 +83,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Float) {
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_Type_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Call<f16>(-1.2e-3_h));
 
@@ -130,7 +130,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_F32) {
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(1_h, 2_h, 3_h));
 
@@ -150,7 +150,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_Empty_F32) {
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_Empty_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>());
 
@@ -170,7 +170,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_SingleScalar_F32_Literal)
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_SingleScalar_F16_Literal) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(2_h));
 
@@ -193,7 +193,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_SingleScalar_F32_Var) {
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Vec_SingleScalar_F16_Var) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("v", Expr(2_h));
     auto* cast = vec3<f16>(var);
@@ -245,7 +245,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Mat_F32) {
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Mat_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(mat2x3<f16>(vec3<f16>(1_h, 2_h, 3_h), vec3<f16>(3_h, 4_h, 5_h)));
 
@@ -291,7 +291,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Mat_Complex_F16) {
     //     vec4<f16>(7.0h),
     //     vec4<f16>(vec4<f16>(42.0h, 21.0h, 6.0h, -5.0h)),
     //   );
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vector_literal =
         vec4<f16>(Expr(f16(2.0)), Expr(f16(3.0)), Expr(f16(4.0)), Expr(f16(8.0)));
@@ -325,7 +325,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Mat_Empty_F32) {
 }
 
 TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Mat_Empty_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(mat2x3<f16>());
 
@@ -361,7 +361,7 @@ TEST_F(MslGeneratorImplTest, EmitInitializer_Type_Mat_Identity_F16) {
     //     var m_2: mat4x4<f16> = mat4x4<f16>(m_1);
     // }
 
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* m_1 = Var("m_1", ty.mat4x4(ty.f16()), mat4x4<f16>());
     auto* m_2 = Var("m_2", ty.mat4x4(ty.f16()), mat4x4<f16>(m_1));

src/tint/writer/msl/generator_impl_module_constant_test.cc

@@ -113,7 +113,7 @@ void f() {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_GlobalConst_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", Expr(1_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(Let("l", Expr(var)))});
@@ -187,7 +187,7 @@ void f() {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_GlobalConst_vec3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", vec3<f16>(1_h, 2_h, 3_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(Let("l", Expr(var)))});
@@ -243,7 +243,7 @@ void f() {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_GlobalConst_mat2x3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalConst("G", mat2x3<f16>(1_h, 2_h, 3_h, 4_h, 5_h, 6_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(Let("l", Expr(var)))});

src/tint/writer/msl/generator_impl_test.cc

@@ -32,7 +32,7 @@ TEST_F(MslGeneratorImplTest, InvalidProgram) {
 }
 
 TEST_F(MslGeneratorImplTest, UnsupportedExtension) {
-    Enable(Source{{12, 34}}, ast::Extension::kUndefined);
+    Enable(Source{{12, 34}}, builtin::Extension::kUndefined);
 
     GeneratorImpl& gen = Build();
 

src/tint/writer/msl/generator_impl_variable_decl_statement_test.cc

@@ -155,7 +155,7 @@ void f() {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Const_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", Expr(1_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(C), Decl(Let("l", Expr(C)))});
@@ -229,7 +229,7 @@ void f() {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Const_vec3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", vec3<f16>(1_h, 2_h, 3_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(C), Decl(Let("l", Expr(C)))});
@@ -285,7 +285,7 @@ void f() {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Const_mat2x3_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* C = Const("C", mat2x3<f16>(1_h, 2_h, 3_h, 4_h, 5_h, 6_h));
     Func("f", utils::Empty, ty.void_(), utils::Vector{Decl(C), Decl(Let("l", Expr(C)))});
@@ -415,7 +415,7 @@ TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Vector_f32) {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.vec2<f16>());
     auto* stmt = Decl(var);
@@ -444,7 +444,7 @@ TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Matrix_f32) {
 }
 
 TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Matrix_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.mat3x2<f16>());
 
@@ -473,7 +473,7 @@ TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Initializer_ZeroVec_f32)
 }
 
 TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Initializer_ZeroVec_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.vec3<f16>(), vec3<f16>());
 
@@ -502,7 +502,7 @@ TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Initializer_ZeroMat_f32)
 }
 
 TEST_F(MslGeneratorImplTest, Emit_VariableDeclStatement_Initializer_ZeroMat_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("a", ty.mat2x3<f16>(), mat2x3<f16>());
 

src/tint/writer/spirv/builder.cc

@@ -265,11 +265,11 @@ Builder::~Builder() = default;
 bool Builder::Build() {
     if (!CheckSupportedExtensions("SPIR-V", builder_.AST(), builder_.Diagnostics(),
                                   utils::Vector{
-                                      ast::Extension::kChromiumDisableUniformityAnalysis,
-                                      ast::Extension::kChromiumExperimentalDp4A,
-                                      ast::Extension::kChromiumExperimentalFullPtrParameters,
-                                      ast::Extension::kChromiumExperimentalPushConstant,
-                                      ast::Extension::kF16,
+                                      builtin::Extension::kChromiumDisableUniformityAnalysis,
+                                      builtin::Extension::kChromiumExperimentalDp4A,
+                                      builtin::Extension::kChromiumExperimentalFullPtrParameters,
+                                      builtin::Extension::kChromiumExperimentalPushConstant,
+                                      builtin::Extension::kF16,
                                   })) {
         error_ = builder_.Diagnostics().str();
         return false;
@@ -394,14 +394,14 @@ void Builder::push_extension(const char* extension) {
     extensions_.push_back(Instruction{spv::Op::OpExtension, {Operand(extension)}});
 }
 
-bool Builder::GenerateExtension(ast::Extension extension) {
+bool Builder::GenerateExtension(builtin::Extension extension) {
     switch (extension) {
-        case ast::Extension::kChromiumExperimentalDp4A:
+        case builtin::Extension::kChromiumExperimentalDp4A:
             push_extension("SPV_KHR_integer_dot_product");
             push_capability(SpvCapabilityDotProductKHR);
             push_capability(SpvCapabilityDotProductInput4x8BitPackedKHR);
             break;
-        case ast::Extension::kF16:
+        case builtin::Extension::kF16:
             push_capability(SpvCapabilityFloat16);
             push_capability(SpvCapabilityUniformAndStorageBuffer16BitAccess);
             push_capability(SpvCapabilityStorageBuffer16BitAccess);

src/tint/writer/spirv/builder.h

@@ -228,7 +228,7 @@ class Builder {
     /// not supported.
     /// @param ext the extension to generate
     /// @returns true on success.
-    bool GenerateExtension(ast::Extension ext);
+    bool GenerateExtension(builtin::Extension ext);
     /// Generates a label for the given id. Emits an error and returns false if
     /// we're currently outside a function.
     /// @param id the id to use for the label

src/tint/writer/spirv/builder_binary_expression_test.cc

@@ -248,7 +248,7 @@ INSTANTIATE_TEST_SUITE_P(BuilderTest,
 
 using BinaryArithF16Test = TestParamHelper<BinaryData>;
 TEST_P(BinaryArithF16Test, Scalar) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
 
@@ -273,7 +273,7 @@ TEST_P(BinaryArithF16Test, Scalar) {
 }
 
 TEST_P(BinaryArithF16Test, Vector) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
 
@@ -543,7 +543,7 @@ INSTANTIATE_TEST_SUITE_P(
 
 using BinaryCompareF16Test = TestParamHelper<BinaryData>;
 TEST_P(BinaryCompareF16Test, Scalar) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
 
@@ -569,7 +569,7 @@ TEST_P(BinaryCompareF16Test, Scalar) {
 }
 
 TEST_P(BinaryCompareF16Test, Vector) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
 
@@ -629,7 +629,7 @@ TEST_F(BuilderTest, Binary_Multiply_VectorScalar_F32) {
 }
 
 TEST_F(BuilderTest, Binary_Multiply_VectorScalar_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* lhs = vec3<f16>(1_h, 1_h, 1_h);
     auto* rhs = Expr(1_h);
@@ -677,7 +677,7 @@ TEST_F(BuilderTest, Binary_Multiply_ScalarVector_F32) {
 }
 
 TEST_F(BuilderTest, Binary_Multiply_ScalarVector_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* lhs = Expr(1_h);
     auto* rhs = vec3<f16>(1_h, 1_h, 1_h);
@@ -728,7 +728,7 @@ TEST_F(BuilderTest, Binary_Multiply_MatrixScalar_F32) {
 }
 
 TEST_F(BuilderTest, Binary_Multiply_MatrixScalar_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("mat", ty.mat3x3<f16>());
     auto* expr = create<ast::BinaryExpression>(ast::BinaryOp::kMultiply, Expr("mat"), Expr(1_h));
@@ -782,7 +782,7 @@ TEST_F(BuilderTest, Binary_Multiply_ScalarMatrix_F32) {
 }
 
 TEST_F(BuilderTest, Binary_Multiply_ScalarMatrix_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("mat", ty.mat3x3<f16>());
     auto* expr = create<ast::BinaryExpression>(ast::BinaryOp::kMultiply, Expr(1_h), Expr("mat"));
@@ -838,7 +838,7 @@ TEST_F(BuilderTest, Binary_Multiply_MatrixVector_F32) {
 }
 
 TEST_F(BuilderTest, Binary_Multiply_MatrixVector_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("mat", ty.mat3x3<f16>());
     auto* rhs = vec3<f16>(1_h, 1_h, 1_h);
@@ -896,7 +896,7 @@ TEST_F(BuilderTest, Binary_Multiply_VectorMatrix_F32) {
 }
 
 TEST_F(BuilderTest, Binary_Multiply_VectorMatrix_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("mat", ty.mat3x3<f16>());
     auto* lhs = vec3<f16>(1_h, 1_h, 1_h);
@@ -953,7 +953,7 @@ TEST_F(BuilderTest, Binary_Multiply_MatrixMatrix_F32) {
 }
 
 TEST_F(BuilderTest, Binary_Multiply_MatrixMatrix_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Var("mat", ty.mat3x3<f16>());
     auto* expr = create<ast::BinaryExpression>(ast::BinaryOp::kMultiply, Expr("mat"), Expr("mat"));
@@ -1341,7 +1341,7 @@ TEST_P(BinaryArithVectorScalarTest, VectorScalar) {
     auto& param = GetParam();
 
     if (param.type == Type::f16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
     }
 
     const ast::Expression* lhs = MakeVectorExpr(this, param.type);
@@ -1393,7 +1393,7 @@ TEST_P(BinaryArithVectorScalarTest, ScalarVector) {
     auto& param = GetParam();
 
     if (param.type == Type::f16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
     }
 
     const ast::Expression* lhs = MakeScalarExpr(this, param.type);
@@ -1473,7 +1473,7 @@ TEST_P(BinaryArithVectorScalarMultiplyTest, VectorScalar) {
     auto& param = GetParam();
 
     if (param.type == Type::f16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
     }
 
     const ast::Expression* lhs = MakeVectorExpr(this, param.type);
@@ -1521,7 +1521,7 @@ TEST_P(BinaryArithVectorScalarMultiplyTest, ScalarVector) {
     auto& param = GetParam();
 
     if (param.type == Type::f16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
     }
 
     const ast::Expression* lhs = MakeScalarExpr(this, param.type);
@@ -1636,7 +1636,7 @@ TEST_P(BinaryArithMatrixMatrix, AddOrSubtract) {
     auto& param = GetParam();
 
     if (param.type == Type::f16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
     }
 
     const ast::Expression* lhs = MakeMat3x4Expr(this, param.type);
@@ -1699,7 +1699,7 @@ TEST_P(BinaryArithMatrixMatrixMultiply, Multiply) {
     auto& param = GetParam();
 
     if (param.type == Type::f16) {
-        Enable(ast::Extension::kF16);
+        Enable(builtin::Extension::kF16);
     }
 
     const ast::Expression* lhs = MakeMat3x4Expr(this, param.type);

src/tint/writer/spirv/builder_builtin_test.cc

@@ -132,7 +132,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_GLSLMethod_WithLoad_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("ident", ty.f16(), type::AddressSpace::kPrivate);
     auto* expr = Call("round", "ident");
@@ -516,7 +516,7 @@ OpFunctionEnd
 }
 
 TEST_P(Builtin_Builder_SingleParam_Float_Test, Call_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
     // Use a variable to prevent the function being evaluated as constant.
@@ -599,7 +599,7 @@ OpFunctionEnd
 }
 
 TEST_P(Builtin_Builder_SingleParam_Float_Test, Call_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
 
@@ -705,7 +705,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Length_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* scalar = Var("a", Expr(1_h));
     auto* expr = Call("length", scalar);
@@ -779,7 +779,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Length_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("a", vec2<f16>(1_h, 1_h));
     auto* expr = Call("length", vec);
@@ -855,7 +855,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Normalize_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("a", vec2<f16>(1_h, 1_h));
     auto* expr = Call("normalize", vec);
@@ -934,7 +934,7 @@ OpFunctionEnd
 }
 
 TEST_P(Builtin_Builder_DualParam_Float_Test, Call_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
     auto* scalar = Var("scalar", Expr(1_h));
@@ -1016,7 +1016,7 @@ OpFunctionEnd
 }
 
 TEST_P(Builtin_Builder_DualParam_Float_Test, Call_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
     auto* vec = Var("vec", vec2<f16>(1_h, 1_h));
@@ -1105,7 +1105,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Reflect_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("vec", vec2<f16>(1_h, 1_h));
     auto* expr = Call("reflect", vec, vec);
@@ -1181,7 +1181,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Distance_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* scalar = Var("scalar", Expr(1_h));
     auto* expr = Call("distance", scalar, scalar);
@@ -1257,7 +1257,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Distance_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("vec", vec2<f16>(1_h, 1_h));
     auto* expr = Call("distance", vec, vec);
@@ -1335,7 +1335,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Cross_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("vec", vec3<f16>(1_h, 1_h, 1_h));
     auto* expr = Call("cross", vec, vec);
@@ -1416,7 +1416,7 @@ OpFunctionEnd
 }
 
 TEST_P(Builtin_Builder_ThreeParam_Float_Test, Call_Scalar_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
     auto* scalar = Var("scalar", Expr(1_h));
@@ -1500,7 +1500,7 @@ OpFunctionEnd
 }
 
 TEST_P(Builtin_Builder_ThreeParam_Float_Test, Call_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto param = GetParam();
     auto* vec = Var("vec", vec2<f16>(1_h, 1_h));
@@ -1591,7 +1591,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_FaceForward_Vector_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("vec", vec2<f16>(1_h, 1_h));
     auto* expr = Call("faceForward", vec, vec, vec);
@@ -1684,7 +1684,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Runtime_Call_Modf_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("vec", vec2<f16>(1_h, 2_h));
     auto* expr = Call("modf", vec);
@@ -1786,7 +1786,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Const_Call_Modf_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* expr = Call("modf", vec2<f16>(1_h, 2_h));
     Func("a_func", utils::Empty, ty.void_(),
@@ -1890,7 +1890,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Runtime_Call_Frexp_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* vec = Var("vec", vec2<f16>(1_h, 2_h));
     auto* expr = Call("frexp", vec);
@@ -1995,7 +1995,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Const_Call_Frexp_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     Func("a_func", utils::Empty, ty.void_(),
          utils::Vector{
@@ -3149,7 +3149,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Determinant_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("var", ty.mat3x3<f16>(), type::AddressSpace::kPrivate);
     auto* expr = Call("determinant", "var");
@@ -3222,7 +3222,7 @@ OpFunctionEnd
 }
 
 TEST_F(BuiltinBuilderTest, Call_Transpose_f16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("var", ty.mat2x3<f16>(), type::AddressSpace::kPrivate);
     auto* expr = Call("transpose", "var");
@@ -3294,7 +3294,7 @@ OpReturn
 }
 
 TEST_F(BuiltinBuilderTest, Call_Dot_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("v", ty.vec3<f16>(), type::AddressSpace::kPrivate);
     auto* expr = Call("dot", "v", "v");
@@ -4153,7 +4153,7 @@ namespace DP4A_builtin_tests {
 TEST_F(BuiltinBuilderTest, Call_Dot4I8Packed) {
     auto* ext =
         create<ast::Enable>(Source{Source::Range{Source::Location{10, 2}, Source::Location{10, 5}}},
-                            ast::Extension::kChromiumExperimentalDp4A);
+                            builtin::Extension::kChromiumExperimentalDp4A);
     AST().AddEnable(ext);
 
     auto* val1 = Var("val1", ty.u32());
@@ -4193,7 +4193,7 @@ OpFunctionEnd
 TEST_F(BuiltinBuilderTest, Call_Dot4U8Packed) {
     auto* ext =
         create<ast::Enable>(Source{Source::Range{Source::Location{10, 2}, Source::Location{10, 5}}},
-                            ast::Extension::kChromiumExperimentalDp4A);
+                            builtin::Extension::kChromiumExperimentalDp4A);
     AST().AddEnable(ext);
 
     auto* val1 = Var("val1", ty.u32());

src/tint/writer/spirv/builder_global_variable_test.cc

@@ -119,7 +119,7 @@ TEST_F(BuilderTest, GlobalConst_Vec_Initializer) {
 TEST_F(BuilderTest, GlobalConst_Vec_F16_Initializer) {
     // const c = vec3<f16>(1h, 2h, 3h);
     // var v = c;
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* c = GlobalConst("c", vec3<f16>(1_h, 2_h, 3_h));
     GlobalVar("v", type::AddressSpace::kPrivate, Expr(c));

src/tint/writer/spirv/builder_initializer_expression_test.cc

@@ -213,7 +213,7 @@ TEST_F(SpvBuilderInitializerTest, Type_F32_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_F16_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = Call<f16>(2_h);
     WrapInFunction(cast);
@@ -288,7 +288,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec2_With_F32_Literal) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec2_With_F16_Literal) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec2<f16>(2_h);
     WrapInFunction(cast);
@@ -332,7 +332,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec2_With_F32_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec2_With_F16_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2_h)));
     auto* cast = vec2<f16>("x", "x");
@@ -377,7 +377,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec2_With_F32_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec2_With_F16_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec2<f16>(1_h, 2_h);
     WrapInFunction(cast);
@@ -422,7 +422,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec2_F32_With_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec2_F16_With_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec2<f16>(), vec2<f16>(1_h, 2_h)));
     auto* cast = vec2<f16>("x");
@@ -467,7 +467,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec2_F32_With_Vec2_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec2_F16_With_Vec2_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec2<f16>(vec2<f16>(1_h, 2_h));
     WrapInFunction(cast);
@@ -513,7 +513,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2_h)));
     auto* cast = vec3<f16>("x", "x", "x");
@@ -560,7 +560,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(1_h, 2_h, 3_h);
     WrapInFunction(cast);
@@ -651,7 +651,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F32_F32_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F16_F16_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2_h)));
     auto* cast = vec3<f16>("x", "x", "x");
@@ -698,7 +698,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F32_F32_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F16_F16_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(1_h, 2_h, 3_h);
     WrapInFunction(cast);
@@ -749,7 +749,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F32_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F16_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec2<f16>(), vec2<f16>(2_h, 3_h)));
     auto* cast = vec3<f16>(1_h, "x");
@@ -800,7 +800,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F32_Vec2_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_F16_Vec2_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(1_h, vec2<f16>(2_h, 3_h));
     WrapInFunction(cast);
@@ -851,7 +851,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_Vec2_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_Vec2_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec2<f16>(), vec2<f16>(1_h, 2_h)));
     auto* cast = vec3<f16>("x", 3_h);
@@ -902,7 +902,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_Vec2_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_With_Vec2_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(vec2<f16>(1_h, 2_h), 3_h);
     WrapInFunction(cast);
@@ -949,7 +949,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_F32_With_Vec3) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_F16_With_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec3<f16>(), vec3<f16>(1_h, 2_h, 3_h)));
     auto* cast = vec3<f16>("x");
@@ -996,7 +996,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec3_F32_With_Vec3_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec3_F16_With_Vec3_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(vec3<f16>(1_h, 2_h, 3_h));
     WrapInFunction(cast);
@@ -1082,7 +1082,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2_h)));
     auto* cast = vec4<f16>("x");
@@ -1125,7 +1125,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h);
     WrapInFunction(cast);
@@ -1171,7 +1171,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_F32_F32_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_F16_F16_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2_h)));
     auto* cast = vec4<f16>("x", "x", "x", "x");
@@ -1220,7 +1220,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_F32_F32_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_F16_F16_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(1_h, 2_h, 3_h, 4_h);
     WrapInFunction(cast);
@@ -1271,7 +1271,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_F32_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_F16_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec2<f16>(), vec2<f16>(1_h, 2_h)));
     auto* cast = vec4<f16>(1_h, 2_h, "x");
@@ -1322,7 +1322,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_F32_Vec2_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_F16_Vec2_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(1_h, 2_h, vec2<f16>(3_h, 4_h));
     WrapInFunction(cast);
@@ -1375,7 +1375,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_Vec2_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_Vec2_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec2<f16>(), vec2<f16>(2_h, 3_h)));
     auto* cast = vec4<f16>(1_h, "x", 4_h);
@@ -1428,7 +1428,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_Vec2_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_Vec2_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(1_h, vec2<f16>(2_h, 3_h), 4_h);
     WrapInFunction(cast);
@@ -1481,7 +1481,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec2_F32_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec2_F16_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec2<f16>(), vec2<f16>(1_h, 2_h)));
     auto* cast = vec4<f16>("x", 3_h, 4_h);
@@ -1534,7 +1534,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec2_F32_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec2_F16_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec2<f16>(1_h, 2_h), 3_h, 4_h);
     WrapInFunction(cast);
@@ -1588,7 +1588,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_F32_With_Vec2_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_F16_With_Vec2_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec2<f16>(), vec2<f16>(1_h, 2_h)));
     auto* cast = vec4<f16>("x", "x");
@@ -1640,7 +1640,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_F32_With_Vec2_Vec2_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_F16_With_Vec2_Vec2_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec2<f16>(1_h, 2_h), vec2<f16>(1_h, 2_h));
     WrapInFunction(cast);
@@ -1689,7 +1689,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_Vec3) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec3<f16>(), vec3<f16>(2_h, 2_h, 2_h)));
     auto* cast = vec4<f16>(2_h, "x");
@@ -1737,7 +1737,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F32_Vec3_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_F16_Vec3_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h, vec3<f16>(2_h, 2_h, 2_h));
     WrapInFunction(cast);
@@ -1785,7 +1785,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec3_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec3_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.vec3<f16>(), vec3<f16>(2_h, 2_h, 2_h)));
     auto* cast = vec4<f16>("x", 2_h);
@@ -1833,7 +1833,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec3_F32_Const) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_With_Vec3_F16_Const) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec3<f16>(2_h, 2_h, 2_h), 2_h);
     WrapInFunction(cast);
@@ -1870,7 +1870,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Vec4_F32_With_Vec4) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Vec4_F16_With_Vec4) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* value = vec4<f16>(2_h, 2_h, 2_h, 2_h);
     auto* cast = vec4<f16>(value);
@@ -1911,7 +1911,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_F16_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* ctor = Call<f16>(2_h);
     GlobalConst("g", ty.f16(), ctor);
@@ -1951,7 +1951,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_F32_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_F16_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* ctor = Call<f16>(2_h);
     GlobalVar("g", ty.f16(), type::AddressSpace::kPrivate, ctor);
@@ -1991,7 +1991,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_U32_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* ctor = Call<u32>(1.5_h);
     GlobalConst("g", ty.u32(), ctor);
@@ -2031,7 +2031,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_U32_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_U32_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* ctor = Call<u32>(1.5_h);
     GlobalVar("g", ty.u32(), type::AddressSpace::kPrivate, ctor);
@@ -2073,7 +2073,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec2_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec2<f16>(2_h);
     GlobalConst("g", ty.vec2<f16>(), cast);
@@ -2114,7 +2114,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec2_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec2_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec2<f16>(2_h);
     auto* g = GlobalVar("g", ty.vec2<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2155,7 +2155,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec2_F16_With_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec2<f16>(vec2<f16>(2_h, 2_h));
     GlobalConst("g", ty.vec2<f16>(), cast);
@@ -2200,7 +2200,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec2_F32_With_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec2_F16_With_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec2<f16>(vec2<f16>(2_h, 2_h));
     GlobalVar("a", ty.vec2<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2245,7 +2245,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec3_F16_With_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(vec3<f16>(2_h, 2_h, 2_h));
     GlobalConst("g", ty.vec3<f16>(), cast);
@@ -2290,7 +2290,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_F32_With_Vec3) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_F16_With_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(vec3<f16>(2_h, 2_h, 2_h));
     GlobalVar("a", ty.vec3<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2335,7 +2335,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec4_F16_With_Vec4) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec4<f16>(2_h, 2_h, 2_h, 2_h));
     GlobalConst("g", ty.vec4<f16>(), cast);
@@ -2380,7 +2380,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_F32_With_Vec4) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_F16_With_Vec4) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec4<f16>(2_h, 2_h, 2_h, 2_h));
     GlobalVar("a", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2425,7 +2425,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec3_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(2_h);
     GlobalConst("g", ty.vec3<f16>(), cast);
@@ -2466,7 +2466,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(2_h);
     auto* g = GlobalVar("g", ty.vec3<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2507,7 +2507,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec3_With_F16_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(2_h, vec2<f16>(2_h, 2_h));
     GlobalConst("g", ty.vec3<f16>(), cast);
@@ -2548,7 +2548,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_With_F32_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_With_F16_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(2_h, vec2<f16>(2_h, 2_h));
     auto* g = GlobalVar("g", ty.vec3<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2589,7 +2589,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec3_With_Vec2_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(vec2<f16>(2_h, 2_h), 2_h);
     GlobalConst("g", ty.vec3<f16>(), cast);
@@ -2630,7 +2630,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_With_Vec2_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec3_With_Vec2_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(vec2<f16>(2_h, 2_h), 2_h);
     auto* g = GlobalVar("g", ty.vec3<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2671,7 +2671,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec4_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h);
     GlobalConst("g", ty.vec4<f16>(), cast);
@@ -2712,7 +2712,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h);
     auto* g = GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2753,7 +2753,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec4_With_F16_F16_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h, 2_h, vec2<f16>(2_h, 2_h));
     GlobalConst("g", ty.vec4<f16>(), cast);
@@ -2794,7 +2794,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F32_F32_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F16_F16_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h, 2_h, vec2<f16>(2_h, 2_h));
     auto* g = GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2835,7 +2835,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec4_With_F16_Vec2_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h, vec2<f16>(2_h, 2_h), 2_h);
     GlobalConst("g", ty.vec4<f16>(), cast);
@@ -2876,7 +2876,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F32_Vec2_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F16_Vec2_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h, vec2<f16>(2_h, 2_h), 2_h);
     auto* g = GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2917,7 +2917,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec4_With_Vec2_F16_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec2<f16>(2_h, 2_h), 2_h, 2_h);
     GlobalConst("g", ty.vec4<f16>(), cast);
@@ -2958,7 +2958,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_Vec2_F32_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_Vec2_F16_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec2<f16>(2_h, 2_h), 2_h, 2_h);
     auto* g = GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -2999,7 +2999,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec4_F16_With_Vec2_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec2<f16>(2_h, 2_h), vec2<f16>(2_h, 2_h));
     GlobalConst("g", ty.vec4<f16>(), cast);
@@ -3040,7 +3040,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_F32_With_Vec2_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_F16_With_Vec2_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec2<f16>(2_h, 2_h), vec2<f16>(2_h, 2_h));
     auto* g = GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -3097,7 +3097,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F32_Vec3) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_F16_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(2_h, vec3<f16>(2_h, 2_h, 2_h));
     auto* g = GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -3138,7 +3138,7 @@ OpReturn
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalConst_Vec4_With_Vec3_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec3<f16>(2_h, 2_h, 2_h), 2_h);
     GlobalConst("g", ty.vec4<f16>(), cast);
@@ -3179,7 +3179,7 @@ TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_Vec3_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_GlobalVar_Vec4_With_Vec3_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec4<f16>(vec3<f16>(2_h, 2_h, 2_h), 2_h);
     auto* g = GlobalVar("g", ty.vec4<f16>(), type::AddressSpace::kPrivate, cast);
@@ -3215,7 +3215,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat2x2_F32_With_Vec2_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat2x2_F16_With_Vec2_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat2x2<f16>(vec2<f16>(2_h, 2_h), vec2<f16>(2_h, 2_h));
     WrapInFunction(cast);
@@ -3253,7 +3253,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat3x2_F32_With_Vec2_Vec2_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat3x2_F16_With_Vec2_Vec2_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat3x2<f16>(vec2<f16>(2_h, 2_h), vec2<f16>(2_h, 2_h), vec2<f16>(2_h, 2_h));
     WrapInFunction(cast);
@@ -3292,7 +3292,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat4x2_F32_With_Vec2_Vec2_Vec2_Vec2) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat4x2_F16_With_Vec2_Vec2_Vec2_Vec2) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat4x2<f16>(vec2<f16>(2_h, 2_h), vec2<f16>(2_h, 2_h), vec2<f16>(2_h, 2_h),
                              vec2<f16>(2_h, 2_h));
@@ -3331,7 +3331,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat2x3_F32_With_Vec3_Vec3) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat2x3_F16_With_Vec3_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat2x3<f16>(vec3<f16>(2_h, 2_h, 2_h), vec3<f16>(2_h, 2_h, 2_h));
     WrapInFunction(cast);
@@ -3370,7 +3370,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat3x3_F32_With_Vec3_Vec3_Vec3) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat3x3_F16_With_Vec3_Vec3_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast =
         mat3x3<f16>(vec3<f16>(2_h, 2_h, 2_h), vec3<f16>(2_h, 2_h, 2_h), vec3<f16>(2_h, 2_h, 2_h));
@@ -3410,7 +3410,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat4x3_F32_With_Vec3_Vec3_Vec3_Vec3) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat4x3_F16_With_Vec3_Vec3_Vec3_Vec3) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat4x3<f16>(vec3<f16>(2_h, 2_h, 2_h), vec3<f16>(2_h, 2_h, 2_h),
                              vec3<f16>(2_h, 2_h, 2_h), vec3<f16>(2_h, 2_h, 2_h));
@@ -3449,7 +3449,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat2x4_F32_With_Vec4_Vec4) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat2x4_F16_With_Vec4_Vec4) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat2x4<f16>(vec4<f16>(2_h, 2_h, 2_h, 2_h), vec4<f16>(2_h, 2_h, 2_h, 2_h));
     WrapInFunction(cast);
@@ -3488,7 +3488,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat3x4_F32_With_Vec4_Vec4_Vec4) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat3x4_F16_With_Vec4_Vec4_Vec4) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat3x4<f16>(vec4<f16>(2_h, 2_h, 2_h, 2_h), vec4<f16>(2_h, 2_h, 2_h, 2_h),
                              vec4<f16>(2_h, 2_h, 2_h, 2_h));
@@ -3528,7 +3528,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Mat4x4_F32_With_Vec4_Vec4_Vec4_Vec4) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Mat4x4_F16_With_Vec4_Vec4_Vec4_Vec4) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = mat4x4<f16>(vec4<f16>(2_h, 2_h, 2_h, 2_h), vec4<f16>(2_h, 2_h, 2_h, 2_h),
                              vec4<f16>(2_h, 2_h, 2_h, 2_h), vec4<f16>(2_h, 2_h, 2_h, 2_h));
@@ -3567,7 +3567,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Array_5_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Array_5_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = array<f16, 5>(2_h, 2_h, 2_h, 2_h, 2_h);
     WrapInFunction(cast);
@@ -3609,7 +3609,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Array_2_Vec3_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Array_2_Vec3_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* first = vec3<f16>(1_h, 2_h, 3_h);
     auto* second = vec3<f16>(1_h, 2_h, 3_h);
@@ -3738,7 +3738,7 @@ TEST_F(SpvBuilderInitializerTest, Type_ZeroInit_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_ZeroInit_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* t = Call<f16>();
 
@@ -3845,7 +3845,7 @@ TEST_F(SpvBuilderInitializerTest, Type_ZeroInit_Matrix_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_ZeroInit_Matrix_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* t = mat4x2<f16>();
 
@@ -3952,7 +3952,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_F32_To_I32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_F16_To_I32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2.4_h)));
     auto* cast = Call<i32>("x");
@@ -4026,7 +4026,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_F32_To_U32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_F16_To_U32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2.4_h)));
     auto* cast = Call<u32>("x");
@@ -4100,7 +4100,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_U32_To_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_F16_To_F32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f16(), Expr(2_h)));
     auto* cast = Call<f32>("x");
@@ -4126,7 +4126,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_F16_To_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_I32_To_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.i32(), Expr(2_i)));
     auto* cast = Call<f16>("x");
@@ -4152,7 +4152,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_I32_To_F16) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_U32_To_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.u32(), Expr(2_u)));
     auto* cast = Call<f16>("x");
@@ -4178,7 +4178,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_U32_To_F16) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_F32_To_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = Decl(Var("x", ty.f32(), Expr(2_f)));
     auto* cast = Call<f16>("x");
@@ -4256,7 +4256,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_F32_to_I32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_F16_to_I32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("i", ty.vec3<f16>(), type::AddressSpace::kPrivate);
 
@@ -4336,7 +4336,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_F32_to_U32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_F16_to_U32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("i", ty.vec3<f16>(), type::AddressSpace::kPrivate);
 
@@ -4416,7 +4416,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_U32_to_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_F16_to_F32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("i", ty.vec3<f16>(), type::AddressSpace::kPrivate);
 
@@ -4444,7 +4444,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_F16_to_F32) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_I32_to_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("i", ty.vec3<i32>(), type::AddressSpace::kPrivate);
 
@@ -4472,7 +4472,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_I32_to_F16) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_U32_to_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("i", ty.vec3<u32>(), type::AddressSpace::kPrivate);
 
@@ -4500,7 +4500,7 @@ TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_U32_to_F16) {
 }
 
 TEST_F(SpvBuilderInitializerTest, Type_Convert_Vectors_F32_to_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* var = GlobalVar("i", ty.vec3<f32>(), type::AddressSpace::kPrivate);
 

src/tint/writer/spirv/builder_literal_test.cc

@@ -164,7 +164,7 @@ TEST_F(BuilderTest, Literal_F32_Dedup) {
 }
 
 TEST_F(BuilderTest, Literal_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* i = create<ast::FloatLiteralExpression>(23.245, ast::FloatLiteralExpression::Suffix::kH);
     WrapInFunction(i);
@@ -181,7 +181,7 @@ TEST_F(BuilderTest, Literal_F16) {
 }
 
 TEST_F(BuilderTest, Literal_F16_Dedup) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* i1 = create<ast::FloatLiteralExpression>(23.245, ast::FloatLiteralExpression::Suffix::kH);
     auto* i2 = create<ast::FloatLiteralExpression>(23.245, ast::FloatLiteralExpression::Suffix::kH);

src/tint/writer/spirv/builder_test.cc

@@ -30,7 +30,7 @@ TEST_F(BuilderTest, InvalidProgram) {
 }
 
 TEST_F(BuilderTest, UnsupportedExtension) {
-    Enable(Source{{12, 34}}, ast::Extension::kUndefined);
+    Enable(Source{{12, 34}}, builtin::Extension::kUndefined);
 
     auto program = std::make_unique<Program>(std::move(*this));
     auto result = Generate(program.get(), Options{});

src/tint/writer/spirv/builder_type_test.cc

@@ -320,7 +320,7 @@ TEST_F(BuilderTest_Type, ReturnsGeneratedPtr) {
 }
 
 TEST_F(BuilderTest_Type, GenerateStruct) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* s = Structure("my_struct", utils::Vector{Member("a", ty.f32()), Member("b", ty.f16())});
 
@@ -341,7 +341,7 @@ OpMemberName %1 1 "b"
 }
 
 TEST_F(BuilderTest_Type, GenerateStruct_DecoratedMembers) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* s = Structure("S", utils::Vector{
                                  Member("a", ty.f32()),
@@ -374,7 +374,7 @@ OpMemberDecorate %1 3 Offset 18
 }
 
 TEST_F(BuilderTest_Type, GenerateStruct_DecoratedMembers_Matrix) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* s =
         Structure("S", utils::Vector{
@@ -438,7 +438,7 @@ OpMemberDecorate %1 5 MatrixStride 8
 }
 
 TEST_F(BuilderTest_Type, GenerateStruct_DecoratedMembers_ArraysOfMatrix) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto arr_mat2x2_f32 = ty.array(ty.mat2x2<f32>(), 1_u);  // Singly nested array
     auto arr_mat2x2_f16 = ty.array(ty.mat2x2<f16>(), 1_u);  // Singly nested array

src/tint/writer/wgsl/generator_impl_cast_test.cc

@@ -33,7 +33,7 @@ TEST_F(WgslGeneratorImplTest, EmitExpression_Cast_Scalar_F32_From_I32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitExpression_Cast_Scalar_F16_From_I32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = Call<f16>(1_i);
     WrapInFunction(cast);
@@ -57,7 +57,7 @@ TEST_F(WgslGeneratorImplTest, EmitExpression_Cast_Vector_F32_From_I32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitExpression_Cast_Vector_F16_From_I32) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* cast = vec3<f16>(vec3<i32>(1_i, 2_i, 3_i));
     WrapInFunction(cast);

src/tint/writer/wgsl/generator_impl_enable_test.cc

@@ -20,7 +20,7 @@ namespace {
 using WgslGeneratorImplTest = TestHelper;
 
 TEST_F(WgslGeneratorImplTest, Emit_Enable) {
-    auto* enable = Enable(ast::Extension::kF16);
+    auto* enable = Enable(builtin::Extension::kF16);
 
     GeneratorImpl& gen = Build();
 

src/tint/writer/wgsl/generator_impl_initializer_test.cc

@@ -62,7 +62,7 @@ TEST_F(WgslGeneratorImplTest, EmitInitializer_F32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitInitializer_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     // Use a number close to 1<<16 but whose decimal representation ends in 0.
     WrapInFunction(Expr(f16((1 << 15) - 8)));
@@ -83,7 +83,7 @@ TEST_F(WgslGeneratorImplTest, EmitInitializer_Type_F32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitInitializer_Type_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(Call<f16>(Expr(-1.2e-5_h)));
 
@@ -130,7 +130,7 @@ TEST_F(WgslGeneratorImplTest, EmitInitializer_Type_Vec_F32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitInitializer_Type_Vec_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(vec3<f16>(1_h, 2_h, 3_h));
 
@@ -151,7 +151,7 @@ TEST_F(WgslGeneratorImplTest, EmitInitializer_Type_Mat_F32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitInitializer_Type_Mat_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     WrapInFunction(mat2x3<f16>(vec3<f16>(1_h, 2_h, 3_h), vec3<f16>(3_h, 4_h, 5_h)));
 

src/tint/writer/wgsl/generator_impl_literal_test.cc

@@ -155,7 +155,7 @@ INSTANTIATE_TEST_SUITE_P(Infinity,
 using WgslGenerator_F16LiteralTest = TestParamHelper<F16Data>;
 
 TEST_P(WgslGenerator_F16LiteralTest, Emit) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto* v = Expr(GetParam().value);
 

src/tint/writer/wgsl/generator_impl_type_test.cc

@@ -88,7 +88,7 @@ TEST_F(WgslGeneratorImplTest, EmitType_F32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitType_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto type = Alias("make_type_reachable", ty.f16())->type;
 
@@ -120,7 +120,7 @@ TEST_F(WgslGeneratorImplTest, EmitType_Matrix_F32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitType_Matrix_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto type = Alias("make_type_reachable", ty.mat2x3<f16>())->type;
 
@@ -305,7 +305,7 @@ TEST_F(WgslGeneratorImplTest, EmitType_Vector_F32) {
 }
 
 TEST_F(WgslGeneratorImplTest, EmitType_Vector_F16) {
-    Enable(ast::Extension::kF16);
+    Enable(builtin::Extension::kF16);
 
     auto type = Alias("make_type_reachable", ty.vec3<f16>())->type;