[tint] Fix unshadowing of abstract const users

Unwrap sem::Materialize as well as sem::Load when looking for users of
a renamed declaration.

Fixed: tint:1934
Change-Id: I7d5ade1f902dbdb4cf3b4f7552b78359f5b3ea9a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/132060
Commit-Queue: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>

src/tint/transform/unshadow.cc

@@ -108,7 +108,7 @@ struct Unshadow::State {
         ctx.ReplaceAll(
             [&](const ast::IdentifierExpression* ident) -> const tint::ast::IdentifierExpression* {
                 if (auto* sem_ident = sem.GetVal(ident)) {
-                    if (auto* user = sem_ident->UnwrapLoad()->As<sem::VariableUser>()) {
+                    if (auto* user = sem_ident->Unwrap()->As<sem::VariableUser>()) {
                         if (auto renamed = renamed_to.Find(user->Variable())) {
                             return b.Expr(*renamed);
                         }

src/tint/transform/unshadow_test.cc

@@ -779,5 +779,25 @@ fn F() {
     EXPECT_EQ(expect, str(got));
 }
 
+TEST_F(UnshadowTest, RenamedAbstractConstHasUsers) {
+    auto* src = R"(
+fn v() {
+  const v = 1;
+  let x = v;
+}
+)";
+
+    auto* expect = R"(
+fn v() {
+  const v_1 = 1;
+  let x = v_1;
+}
+)";
+
+    auto got = Run<Unshadow>(src);
+
+    EXPECT_EQ(expect, str(got));
+}
+
 }  // namespace
 }  // namespace tint::transform

test/tint/bug/tint/1934.wgsl

@@ -0,0 +1,5 @@
+fn v() {
+  const v = vec2(1);
+  let i = 1;
+  var b = v[i];
+}

test/tint/bug/tint/1934.wgsl.expected.dxc.hlsl

@@ -0,0 +1,9 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+void v() {
+  const int i = 1;
+  int b = (1).xx[i];
+}

test/tint/bug/tint/1934.wgsl.expected.fxc.hlsl

@@ -0,0 +1,9 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+void v() {
+  const int i = 1;
+  int b = (1).xx[i];
+}

test/tint/bug/tint/1934.wgsl.expected.glsl

@@ -0,0 +1,11 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+void v() {
+  int i = 1;
+  int b = ivec2(1)[i];
+}
+

test/tint/bug/tint/1934.wgsl.expected.msl

@@ -0,0 +1,8 @@
+#include <metal_stdlib>
+
+using namespace metal;
+void v() {
+  int const i = 1;
+  int b = int2(1)[i];
+}
+

test/tint/bug/tint/1934.wgsl.expected.spvasm

@@ -0,0 +1,31 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 15
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %unused_entry_point "unused_entry_point"
+               OpName %v "v"
+               OpName %b "b"
+       %void = OpTypeVoid
+          %1 = OpTypeFunction %void
+        %int = OpTypeInt 32 1
+      %int_1 = OpConstant %int 1
+      %v2int = OpTypeVector %int 2
+         %10 = OpConstantComposite %v2int %int_1 %int_1
+%_ptr_Function_int = OpTypePointer Function %int
+         %14 = OpConstantNull %int
+%unused_entry_point = OpFunction %void None %1
+          %4 = OpLabel
+               OpReturn
+               OpFunctionEnd
+          %v = OpFunction %void None %1
+          %6 = OpLabel
+          %b = OpVariable %_ptr_Function_int Function %14
+         %11 = OpVectorExtractDynamic %int %10 %int_1
+               OpStore %b %11
+               OpReturn
+               OpFunctionEnd

test/tint/bug/tint/1934.wgsl.expected.wgsl

@@ -0,0 +1,5 @@
+fn v() {
+  const v = vec2(1);
+  let i = 1;
+  var b = v[i];
+}