diff --git a/src/tint/resolver/attribute_validation_test.cc b/src/tint/resolver/attribute_validation_test.cc
index ca36e0b583..18200d4214 100644
--- a/src/tint/resolver/attribute_validation_test.cc
+++ b/src/tint/resolver/attribute_validation_test.cc
@@ -54,6 +54,7 @@ enum class AttributeKind {
     kAlign,
     kBinding,
     kBuiltin,
+    kDiagnostic,
     kGroup,
     kId,
     kInterpolate,
@@ -95,6 +96,9 @@ static utils::Vector<const ast::Attribute*, 2> createAttributes(const Source& so
             return {builder.Binding(source, 1_a)};
         case AttributeKind::kBuiltin:
             return {builder.Builtin(source, ast::BuiltinValue::kPosition)};
+        case AttributeKind::kDiagnostic:
+            return {builder.DiagnosticAttribute(source, ast::DiagnosticSeverity::kInfo,
+                                                builder.Expr("chromium_unreachable_code"))};
         case AttributeKind::kGroup:
             return {builder.Group(source, 1_a)};
         case AttributeKind::kId:
@@ -147,6 +151,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -183,6 +188,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -233,6 +239,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -270,6 +277,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, true},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          // kInterpolate tested separately (requires @location)
@@ -323,6 +331,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, true},
@@ -373,6 +382,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -425,6 +435,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, true},
@@ -474,6 +485,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, true},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          // kInterpolate tested separately (requires @location)
@@ -578,6 +590,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -613,6 +626,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, true},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, true},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          // kInterpolate tested separately (requires @location)
@@ -854,6 +868,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -893,6 +908,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -944,6 +960,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, false},
                                          TestParams{AttributeKind::kInterpolate, false},
@@ -987,6 +1004,7 @@ INSTANTIATE_TEST_SUITE_P(ResolverAttributeValidationTest,
                          testing::Values(TestParams{AttributeKind::kAlign, false},
                                          TestParams{AttributeKind::kBinding, false},
                                          TestParams{AttributeKind::kBuiltin, false},
+                                         TestParams{AttributeKind::kDiagnostic, false},
                                          TestParams{AttributeKind::kGroup, false},
                                          TestParams{AttributeKind::kId, true},
                                          TestParams{AttributeKind::kInterpolate, false},