diff --git a/src/transform/bound_array_accessors_test.cc b/src/transform/bound_array_accessors_test.cc
index c5bef53b9e..67a831cf3f 100644
--- a/src/transform/bound_array_accessors_test.cc
+++ b/src/transform/bound_array_accessors_test.cc
@@ -43,7 +43,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -73,7 +73,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -95,7 +95,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -121,7 +121,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -143,7 +143,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -165,7 +165,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -187,7 +187,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -213,7 +213,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -235,7 +235,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -261,7 +261,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -286,7 +286,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -308,7 +308,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -330,7 +330,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -352,7 +352,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -378,7 +378,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -404,7 +404,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -426,7 +426,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -448,7 +448,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -470,7 +470,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -492,7 +492,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -559,7 +559,7 @@ fn f() -> void {
 }
 )";
 
-  auto got = Transform<BoundArrayAccessors>(src);
+  auto got = Run<BoundArrayAccessors>(src);
 
   EXPECT_EQ(expect, str(got));
 }
diff --git a/src/transform/emit_vertex_point_size_test.cc b/src/transform/emit_vertex_point_size_test.cc
index 5fc7dbae99..4d4e5ed859 100644
--- a/src/transform/emit_vertex_point_size_test.cc
+++ b/src/transform/emit_vertex_point_size_test.cc
@@ -52,7 +52,7 @@ fn non_entry_b() -> void {
 }
 )";
 
-  auto got = Transform<EmitVertexPointSize>(src);
+  auto got = Run<EmitVertexPointSize>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -85,7 +85,7 @@ fn non_entry_b() -> void {
 }
 )";
 
-  auto got = Transform<EmitVertexPointSize>(src);
+  auto got = Run<EmitVertexPointSize>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -111,7 +111,7 @@ fn compute_entry() -> void {
 }
 )";
 
-  auto got = Transform<EmitVertexPointSize>(src);
+  auto got = Run<EmitVertexPointSize>(src);
 
   EXPECT_EQ(expect, str(got));
 }
diff --git a/src/transform/first_index_offset_test.cc b/src/transform/first_index_offset_test.cc
index 3370cf4a7e..ef8965b5af 100644
--- a/src/transform/first_index_offset_test.cc
+++ b/src/transform/first_index_offset_test.cc
@@ -47,7 +47,7 @@ fn entry() -> void {
   transforms.emplace_back(std::make_unique<FirstIndexOffset>(0, 0));
   transforms.emplace_back(std::make_unique<FirstIndexOffset>(1, 1));
 
-  auto got = Transform(src, std::move(transforms));
+  auto got = Run(src, std::move(transforms));
 
   EXPECT_EQ(expect, str(got));
 
@@ -64,7 +64,7 @@ TEST_F(FirstIndexOffsetTest, EmptyModule) {
   auto* src = "";
   auto* expect = "";
 
-  auto got = Transform<FirstIndexOffset>(src, 0, 0);
+  auto got = Run<FirstIndexOffset>(src, 0, 0);
 
   EXPECT_EQ(expect, str(got));
 
@@ -112,7 +112,7 @@ fn entry() -> void {
 }
 )";
 
-  auto got = Transform<FirstIndexOffset>(src, 1, 2);
+  auto got = Run<FirstIndexOffset>(src, 1, 2);
 
   EXPECT_EQ(expect, str(got));
 
@@ -160,7 +160,7 @@ fn entry() -> void {
 }
 )";
 
-  auto got = Transform<FirstIndexOffset>(src, 1, 7);
+  auto got = Run<FirstIndexOffset>(src, 1, 7);
 
   EXPECT_EQ(expect, str(got));
 
@@ -213,7 +213,7 @@ fn entry() -> void {
 }
 )";
 
-  auto got = Transform<FirstIndexOffset>(src, 1, 2);
+  auto got = Run<FirstIndexOffset>(src, 1, 2);
 
   EXPECT_EQ(expect, str(got));
 
@@ -269,7 +269,7 @@ fn entry() -> void {
 }
 )";
 
-  auto got = Transform<FirstIndexOffset>(src, 1, 2);
+  auto got = Run<FirstIndexOffset>(src, 1, 2);
 
   EXPECT_EQ(expect, str(got));
 
diff --git a/src/transform/hlsl_test.cc b/src/transform/hlsl_test.cc
index b05fdba0ed..f0d81bdbd5 100644
--- a/src/transform/hlsl_test.cc
+++ b/src/transform/hlsl_test.cc
@@ -46,7 +46,7 @@ fn main() -> void {
 }
 )";
 
-  auto got = Transform<Hlsl>(src);
+  auto got = Run<Hlsl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -69,7 +69,7 @@ fn main() -> void {
 }
 )";
 
-  auto got = Transform<Hlsl>(src);
+  auto got = Run<Hlsl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -86,7 +86,7 @@ const module_arr : array<f32, 4> = array<f32, 4>(0.0, 1.0, 2.0, 3.0);
 
   auto* expect = src;
 
-  auto got = Transform<Hlsl>(src);
+  auto got = Run<Hlsl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -138,7 +138,7 @@ fn main() -> void {
 }
 )";
 
-  auto got = Transform<Hlsl>(src);
+  auto got = Run<Hlsl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
diff --git a/src/transform/msl.cc b/src/transform/msl.cc
index 96f5f04a48..3733d1046a 100644
--- a/src/transform/msl.cc
+++ b/src/transform/msl.cc
@@ -320,7 +320,7 @@ void Msl::HandleEntryPointIOTypes(CloneContext& ctx) const {
       }
 
       auto* deco = param->decorations()[0];
-      if (auto* builtin = deco->As<ast::BuiltinDecoration>()) {
+      if (deco->Is<ast::BuiltinDecoration>()) {
         // Keep any builtin-decorated parameters unchanged.
         builtins.insert(param);
         continue;
diff --git a/src/transform/msl_test.cc b/src/transform/msl_test.cc
index 915d591aac..c6da8c980c 100644
--- a/src/transform/msl_test.cc
+++ b/src/transform/msl_test.cc
@@ -55,7 +55,7 @@ fn _tint_main() -> void {
 }
 )";
 
-  auto got = Transform<Msl>(src);
+  auto got = Run<Msl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -79,7 +79,7 @@ fn _tint_main() -> void {
 }
 )";
 
-  auto got = Transform<Msl>(src);
+  auto got = Run<Msl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -354,7 +354,7 @@ fn frag_main(tint_symbol_4 : tint_symbol_3, [[builtin(frag_coord)]] coord : vec4
 }
 )";
 
-  auto got = Transform<Msl>(src);
+  auto got = Run<Msl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -396,7 +396,7 @@ fn frag_main(tint_symbol_4 : tint_symbol_3, [[builtin(frag_coord)]] coord : vec4
 }
 )";
 
-  auto got = Transform<Msl>(src);
+  auto got = Run<Msl>(src);
 
   EXPECT_EQ(expect, str(got));
 }
diff --git a/src/transform/renamer_test.cc b/src/transform/renamer_test.cc
index 2b3b039f49..887cfaafa9 100644
--- a/src/transform/renamer_test.cc
+++ b/src/transform/renamer_test.cc
@@ -29,7 +29,7 @@ TEST_F(RenamerTest, EmptyModule) {
   auto* src = "";
   auto* expect = "";
 
-  auto got = Transform<Renamer>(src);
+  auto got = Run<Renamer>(src);
 
   EXPECT_EQ(expect, str(got));
 
@@ -65,7 +65,7 @@ fn _tint_3() -> void {
 }
 )";
 
-  auto got = Transform<Renamer>(src);
+  auto got = Run<Renamer>(src);
 
   EXPECT_EQ(expect, str(got));
 
@@ -101,7 +101,7 @@ fn _tint_1() -> void {
 }
 )";
 
-  auto got = Transform<Renamer>(src);
+  auto got = Run<Renamer>(src);
 
   EXPECT_EQ(expect, str(got));
 
@@ -134,7 +134,7 @@ fn _tint_1() -> void {
 }
 )";
 
-  auto got = Transform<Renamer>(src);
+  auto got = Run<Renamer>(src);
 
   EXPECT_EQ(expect, str(got));
 
diff --git a/src/transform/spirv_test.cc b/src/transform/spirv_test.cc
index 2e66ce2dc6..f85e3188e4 100644
--- a/src/transform/spirv_test.cc
+++ b/src/transform/spirv_test.cc
@@ -57,7 +57,7 @@ fn compute_main() -> void {
 }
 )";
 
-  auto got = Transform<Spirv>(src);
+  auto got = Run<Spirv>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -89,7 +89,7 @@ fn main() -> void {
 }
 )";
 
-  auto got = Transform<Spirv>(src);
+  auto got = Run<Spirv>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -133,7 +133,7 @@ fn main() -> void {
 }
 )";
 
-  auto got = Transform<Spirv>(src);
+  auto got = Run<Spirv>(src);
 
   EXPECT_EQ(expect, str(got));
 }
@@ -164,7 +164,7 @@ fn main() -> void {
 }
 )";
 
-  auto got = Transform<Spirv>(src);
+  auto got = Run<Spirv>(src);
 
   EXPECT_EQ(expect, str(got));
 }
diff --git a/src/transform/test_helper.h b/src/transform/test_helper.h
index aa6ae963fe..f8fc8b5306 100644
--- a/src/transform/test_helper.h
+++ b/src/transform/test_helper.h
@@ -37,7 +37,7 @@ class TransformTestBase : public BASE {
   /// @param in the input WGSL source
   /// @param transforms the list of transforms to apply
   /// @return the transformed output
-  Transform::Output Transform(
+  Transform::Output Run(
       std::string in,
       std::vector<std::unique_ptr<transform::Transform>> transforms) {
     auto file = std::make_unique<Source::File>("test", in);
@@ -62,11 +62,11 @@ class TransformTestBase : public BASE {
   /// @param transform the transform to apply
   /// @param in the input WGSL source
   /// @return the transformed output
-  Transform::Output Transform(std::string in,
-                              std::unique_ptr<transform::Transform> transform) {
+  Transform::Output Run(std::string in,
+                        std::unique_ptr<transform::Transform> transform) {
     std::vector<std::unique_ptr<transform::Transform>> transforms;
     transforms.emplace_back(std::move(transform));
-    return Transform(std::move(in), std::move(transforms));
+    return Run(std::move(in), std::move(transforms));
   }
 
   /// Transforms and returns the WGSL source `in`, transformed using
@@ -75,9 +75,9 @@ class TransformTestBase : public BASE {
   /// @param args the TRANSFORM constructor arguments
   /// @return the transformed output
   template <typename TRANSFORM, typename... ARGS>
-  Transform::Output Transform(std::string in, ARGS&&... args) {
-    return Transform(std::move(in),
-                     std::make_unique<TRANSFORM>(std::forward<ARGS>(args)...));
+  Transform::Output Run(std::string in, ARGS&&... args) {
+    return Run(std::move(in),
+               std::make_unique<TRANSFORM>(std::forward<ARGS>(args)...));
   }
 
   /// @param output the output of the transform
diff --git a/src/transform/vertex_pulling_test.cc b/src/transform/vertex_pulling_test.cc
index b4e1080d96..d36dcaaf9f 100644
--- a/src/transform/vertex_pulling_test.cc
+++ b/src/transform/vertex_pulling_test.cc
@@ -33,7 +33,7 @@ TEST_F(VertexPullingTest, Error_NoEntryPoint) {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -51,7 +51,7 @@ fn main() -> void {}
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -69,7 +69,7 @@ fn main() -> void {}
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -99,7 +99,7 @@ fn main() -> void {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -141,7 +141,7 @@ fn main() -> void {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -183,7 +183,7 @@ fn main() -> void {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -226,7 +226,7 @@ fn main() -> void {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -290,7 +290,7 @@ fn main() -> void {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -339,7 +339,7 @@ fn main() -> void {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
@@ -398,7 +398,7 @@ fn main() -> void {
 
   auto transform = std::make_unique<VertexPulling>(cfg);
 
-  auto got = Transform(src, std::move(transform));
+  auto got = Run(src, std::move(transform));
 
   EXPECT_EQ(expect, str(got));
 }
diff --git a/src/validator/validator_decoration_test.cc b/src/validator/validator_decoration_test.cc
index b4dc099a46..58ab2d5576 100644
--- a/src/validator/validator_decoration_test.cc
+++ b/src/validator/validator_decoration_test.cc
@@ -75,6 +75,7 @@ ast::Decoration* createDecoration(ProgramBuilder& builder,
     case DecorationKind::kConstantId:
       return builder.create<ast::ConstantIdDecoration>(0u);
   }
+  return nullptr;
 }
 
 using ArrayDecorationTest = ValidatorDecorationsTestWithParams;