diff --git a/src/ast/bitcast_expression.cc b/src/ast/bitcast_expression.cc
index b2baa53604..2c23b9d6ec 100644
--- a/src/ast/bitcast_expression.cc
+++ b/src/ast/bitcast_expression.cc
@@ -26,7 +26,7 @@ BitcastExpression::BitcastExpression(ProgramID program_id,
                                      typ::Type type,
                                      Expression* expr)
     : Base(program_id, source), type_(type), expr_(expr) {
-  TINT_ASSERT(type_.sem);
+  TINT_ASSERT(type_.ast || type_.sem);
   TINT_ASSERT(expr_);
   TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(expr, program_id);
 }
@@ -46,8 +46,9 @@ void BitcastExpression::to_str(const sem::Info& sem,
                                std::ostream& out,
                                size_t indent) const {
   make_indent(out, indent);
-  out << "Bitcast[" << result_type_str(sem) << "]<" << type_->type_name()
-      << ">{" << std::endl;
+  out << "Bitcast[" << result_type_str(sem) << "]<"
+      << (type_.ast ? type_.ast->type_name() : type_.sem->type_name()) << ">{"
+      << std::endl;
   expr_->to_str(sem, out, indent + 2);
   make_indent(out, indent);
   out << "}" << std::endl;
diff --git a/src/ast/function.cc b/src/ast/function.cc
index 403863ff82..ec7b2f021d 100644
--- a/src/ast/function.cc
+++ b/src/ast/function.cc
@@ -45,7 +45,7 @@ Function::Function(ProgramID program_id,
     TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(param, program_id);
   }
   TINT_ASSERT(symbol_.IsValid());
-  TINT_ASSERT(return_type_.sem);
+  TINT_ASSERT(return_type_.ast || return_type_.sem);
   for (auto* deco : decorations_) {
     TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(deco, program_id);
   }
@@ -92,7 +92,9 @@ void Function::to_str(const sem::Info& sem,
                       std::ostream& out,
                       size_t indent) const {
   make_indent(out, indent);
-  out << "Function " << symbol_.to_str() << " -> " << return_type_->type_name()
+  out << "Function " << symbol_.to_str() << " -> "
+      << (return_type_.ast ? return_type_.ast->type_name()
+                           : return_type_.sem->type_name())
       << std::endl;
 
   for (auto* deco : decorations()) {
diff --git a/src/ast/struct_member.cc b/src/ast/struct_member.cc
index 7fc2fa250b..ca4bde2186 100644
--- a/src/ast/struct_member.cc
+++ b/src/ast/struct_member.cc
@@ -30,7 +30,7 @@ StructMember::StructMember(ProgramID program_id,
       symbol_(sym),
       type_(type),
       decorations_(std::move(decorations)) {
-  TINT_ASSERT(type.sem);
+  TINT_ASSERT(type.ast || type.sem);
   TINT_ASSERT(symbol_.IsValid());
   TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(symbol_, program_id);
   for (auto* deco : decorations_) {
@@ -76,7 +76,9 @@ void StructMember::to_str(const sem::Info& sem,
     out << "]] ";
   }
 
-  out << symbol_.to_str() << ": " << type_->type_name() << "}" << std::endl;
+  out << symbol_.to_str() << ": "
+      << (type_.ast ? type_.ast->type_name() : type_.sem->type_name()) << "}"
+      << std::endl;
 }
 
 }  // namespace ast
diff --git a/src/ast/type_constructor_expression.cc b/src/ast/type_constructor_expression.cc
index 01c0c739c9..51deb0f963 100644
--- a/src/ast/type_constructor_expression.cc
+++ b/src/ast/type_constructor_expression.cc
@@ -26,7 +26,7 @@ TypeConstructorExpression::TypeConstructorExpression(ProgramID program_id,
                                                      typ::Type type,
                                                      ExpressionList values)
     : Base(program_id, source), type_(type), values_(std::move(values)) {
-  TINT_ASSERT(type_.sem);
+  TINT_ASSERT(type_.ast || type_.sem);
   for (auto* val : values_) {
     TINT_ASSERT(val);
     TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(val, program_id);
@@ -53,7 +53,8 @@ void TypeConstructorExpression::to_str(const sem::Info& sem,
   make_indent(out, indent);
   out << "TypeConstructor[" << result_type_str(sem) << "]{" << std::endl;
   make_indent(out, indent + 2);
-  out << type_->type_name() << std::endl;
+  out << (type_.ast ? type_.ast->type_name() : type_.sem->type_name())
+      << std::endl;
 
   for (auto* val : values_) {
     val->to_str(sem, out, indent + 2);
diff --git a/src/ast/variable.cc b/src/ast/variable.cc
index 3837666f23..69a296423d 100644
--- a/src/ast/variable.cc
+++ b/src/ast/variable.cc
@@ -41,7 +41,7 @@ Variable::Variable(ProgramID program_id,
   TINT_ASSERT(symbol_.IsValid());
   TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(symbol_, program_id);
   // no type means we must have a constructor to infer it
-  TINT_ASSERT(type_.sem || constructor);
+  TINT_ASSERT(type_.ast || type_.sem || constructor);
   TINT_ASSERT_PROGRAM_IDS_EQUAL_IF_VALID(constructor, program_id);
 }
 
@@ -90,9 +90,8 @@ void Variable::info_to_str(const sem::Info& sem,
   out << (var_sem ? var_sem->StorageClass() : declared_storage_class())
       << std::endl;
   make_indent(out, indent);
-  if (type_.sem) {
-    out << type_->type_name() << std::endl;
-  }
+  out << (type_.sem ? type_.sem->type_name() : type_.ast->type_name())
+      << std::endl;
 }
 
 void Variable::constructor_to_str(const sem::Info& sem,
diff --git a/src/inspector/inspector_test.cc b/src/inspector/inspector_test.cc
index 8ee6cc4b01..15324a6902 100644
--- a/src/inspector/inspector_test.cc
+++ b/src/inspector/inspector_test.cc
@@ -173,7 +173,8 @@ class InspectorHelper : public ProgramBuilder {
   /// @param type type of member
   /// @returns a string for the member
   std::string StructMemberName(size_t idx, typ::Type type) {
-    return std::to_string(idx) + type->type_name();
+    return std::to_string(idx) +
+           (type.sem ? type.sem->type_name() : type.ast->type_name());
   }
 
   /// Generates a struct type
diff --git a/src/program_builder.h b/src/program_builder.h
index e910ed17e6..a156f2d6ef 100644
--- a/src/program_builder.h
+++ b/src/program_builder.h
@@ -861,6 +861,9 @@ class ProgramBuilder {
     /// @return either type or a pointer to a new ast::TypeName
     typ::Type MaybeCreateTypename(typ::Type type) const;
 
+    /// The ProgramBuilder
+    ProgramBuilder* const builder;
+
    private:
     /// CToAST<T> is specialized for various `T` types and each specialization
     /// contains a single static `get()` method for obtaining the corresponding
@@ -869,8 +872,6 @@ class ProgramBuilder {
     ///    `static typ::Type get(Types* t)`
     template <typename T>
     struct CToAST {};
-
-    ProgramBuilder* const builder;
   };
 
   //////////////////////////////////////////////////////////////////////////////
diff --git a/src/writer/hlsl/generator_impl_member_accessor_test.cc b/src/writer/hlsl/generator_impl_member_accessor_test.cc
index 04efb7da98..9b6d552e74 100644
--- a/src/writer/hlsl/generator_impl_member_accessor_test.cc
+++ b/src/writer/hlsl/generator_impl_member_accessor_test.cc
@@ -26,63 +26,63 @@ namespace {
 using ::testing::HasSubstr;
 
 using create_type_func_ptr =
-    sem::Type* (*)(const ProgramBuilder::TypesBuilder& ty);
+    typ::Type (*)(const ProgramBuilder::TypesBuilder& ty);
 
-inline sem::Type* ty_i32(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_i32(const ProgramBuilder::TypesBuilder& ty) {
   return ty.i32();
 }
-inline sem::Type* ty_u32(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_u32(const ProgramBuilder::TypesBuilder& ty) {
   return ty.u32();
 }
-inline sem::Type* ty_f32(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_f32(const ProgramBuilder::TypesBuilder& ty) {
   return ty.f32();
 }
 template <typename T>
-inline sem::Type* ty_vec2(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_vec2(const ProgramBuilder::TypesBuilder& ty) {
   return ty.vec2<T>();
 }
 template <typename T>
-inline sem::Type* ty_vec3(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_vec3(const ProgramBuilder::TypesBuilder& ty) {
   return ty.vec3<T>();
 }
 template <typename T>
-inline sem::Type* ty_vec4(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_vec4(const ProgramBuilder::TypesBuilder& ty) {
   return ty.vec4<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat2x2(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat2x2(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat2x2<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat2x3(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat2x3(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat2x3<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat2x4(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat2x4(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat2x4<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat3x2(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat3x2(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat3x2<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat3x3(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat3x3(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat3x3<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat3x4(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat3x4(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat3x4<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat4x2(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat4x2(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat4x2<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat4x3(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat4x3(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat4x3<T>();
 }
 template <typename T>
-inline sem::Type* ty_mat4x4(const ProgramBuilder::TypesBuilder& ty) {
+inline typ::Type ty_mat4x4(const ProgramBuilder::TypesBuilder& ty) {
   return ty.mat4x4<T>();
 }
 
@@ -155,8 +155,12 @@ struct TypeCase {
 };
 inline std::ostream& operator<<(std::ostream& out, TypeCase c) {
   ProgramBuilder b;
-  auto* ty = c.member_type(b.ty);
-  out << ty->FriendlyName(b.Symbols());
+  auto ty = c.member_type(b.ty);
+  if (ty.sem) {
+    out << ty.sem->FriendlyName(b.Symbols());
+  } else {
+    out << ty.ast->FriendlyName(b.Symbols());
+  }
   return out;
 }
 
@@ -246,7 +250,7 @@ TEST_P(HlslGeneratorImplTest_MemberAccessor_StorageBufferStore, Test) {
 
   auto p = GetParam();
 
-  auto* type = p.member_type(ty);
+  auto type = p.member_type(ty);
 
   SetupStorageBuffer({
       Member("a", ty.i32()),