diff --git a/fuzzers/dictionary.txt b/fuzzers/dictionary.txt
index baccbb819d..d1394348a9 100644
--- a/fuzzers/dictionary.txt
+++ b/fuzzers/dictionary.txt
@@ -101,7 +101,6 @@
 "type"
 "u32"
 "uniform"
-"uniform_constant"
 "var"
 "vec2"
 "vec3"
diff --git a/src/reader/wgsl/lexer.cc b/src/reader/wgsl/lexer.cc
index 76cc3e9c60..4ce36f0d0f 100644
--- a/src/reader/wgsl/lexer.cc
+++ b/src/reader/wgsl/lexer.cc
@@ -673,8 +673,6 @@ Token Lexer::check_keyword(const Source& source, const std::string& str) {
     return {Token::Type::kU32, source, "u32"};
   if (str == "uniform")
     return {Token::Type::kUniform, source, "uniform"};
-  if (str == "uniform_constant")
-    return {Token::Type::kUniformConstant, source, "uniform_constant"};
   if (str == "var")
     return {Token::Type::kVar, source, "var"};
   if (str == "vec2")
diff --git a/src/reader/wgsl/lexer_test.cc b/src/reader/wgsl/lexer_test.cc
index 5d01df1c8a..1d80b29935 100644
--- a/src/reader/wgsl/lexer_test.cc
+++ b/src/reader/wgsl/lexer_test.cc
@@ -518,7 +518,6 @@ INSTANTIATE_TEST_SUITE_P(
         TokenData{"type", Token::Type::kType},
         TokenData{"u32", Token::Type::kU32},
         TokenData{"uniform", Token::Type::kUniform},
-        TokenData{"uniform_constant", Token::Type::kUniformConstant},
         TokenData{"var", Token::Type::kVar},
         TokenData{"vec2", Token::Type::kVec2},
         TokenData{"vec3", Token::Type::kVec3},
diff --git a/src/reader/wgsl/parser_impl.cc b/src/reader/wgsl/parser_impl.cc
index 6010c47c8e..53036cbb75 100644
--- a/src/reader/wgsl/parser_impl.cc
+++ b/src/reader/wgsl/parser_impl.cc
@@ -459,7 +459,12 @@ Maybe<ParserImpl::VarDeclInfo> ParserImpl::variable_decl() {
 
   if (decl->type->UnwrapAll()->is_handle()) {
     // handle types implicitly have the `UniformConstant` storage class.
-    // TODO(jrprice): Produce an error if an explicit storage class is provided.
+    if (explicit_sc.matched) {
+      return add_error(
+          explicit_sc.source,
+          decl->type->UnwrapAll()->FriendlyName(builder_.Symbols()) +
+              " variables must not have a storage class");
+    }
     sc = ast::StorageClass::kUniformConstant;
   }
 
@@ -1049,7 +1054,6 @@ Expect<type::Type*> ParserImpl::expect_type_decl_matrix(Token t) {
 //  | OUTPUT
 //  | UNIFORM
 //  | WORKGROUP
-//  | UNIFORM_CONSTANT
 //  | STORAGE
 //  | IMAGE
 //  | PRIVATE
@@ -1070,9 +1074,6 @@ Expect<ast::StorageClass> ParserImpl::expect_storage_class(
   if (match(Token::Type::kWorkgroup))
     return {ast::StorageClass::kWorkgroup, source};
 
-  if (match(Token::Type::kUniformConstant))
-    return {ast::StorageClass::kUniformConstant, source};
-
   if (match(Token::Type::kStorage))
     return {ast::StorageClass::kStorage, source};
 
diff --git a/src/reader/wgsl/parser_impl_error_msg_test.cc b/src/reader/wgsl/parser_impl_error_msg_test.cc
index 00cd58f915..4dd48712ca 100644
--- a/src/reader/wgsl/parser_impl_error_msg_test.cc
+++ b/src/reader/wgsl/parser_impl_error_msg_test.cc
@@ -1110,8 +1110,7 @@ TEST_F(ParserImplErrorTest, GlobalDeclVarVectorMissingType) {
          "             ^\n");
 }
 
-TEST_F(ParserImplErrorTest, DISABLED_GlobalDeclSamplerExplicitStorageClass) {
-  // TODO(jrprice): Enable this once downstream users have caught up.
+TEST_F(ParserImplErrorTest, GlobalDeclSamplerExplicitStorageClass) {
   EXPECT(
       "var<uniform> x : sampler;",
       "test.wgsl:1:5 error: sampler variables must not have a storage class\n"
@@ -1119,13 +1118,12 @@ TEST_F(ParserImplErrorTest, DISABLED_GlobalDeclSamplerExplicitStorageClass) {
       "    ^^^^^^^\n");
 }
 
-TEST_F(ParserImplErrorTest, DISABLED_GlobalDeclTextureExplicitStorageClass) {
-  // TODO(jrprice): Enable this once downstream users have caught up.
-  EXPECT(
-      "var<uniform> x : [[access(read)]] texture_1d<f32>;",
-      "test.wgsl:1:5 error: texture variables must not have a storage class\n"
-      "var<uniform> x : [[access(read)]] texture_1d<f32>;\n"
-      "    ^^^^^^^\n");
+TEST_F(ParserImplErrorTest, GlobalDeclTextureExplicitStorageClass) {
+  EXPECT("var<uniform> x : [[access(read)]] texture_1d<f32>;",
+         "test.wgsl:1:5 error: texture_1d<f32> variables must not have a "
+         "storage class\n"
+         "var<uniform> x : [[access(read)]] texture_1d<f32>;\n"
+         "    ^^^^^^^\n");
 }
 
 TEST_F(ParserImplErrorTest, IfStmtMissingLParen) {
diff --git a/src/reader/wgsl/parser_impl_storage_class_test.cc b/src/reader/wgsl/parser_impl_storage_class_test.cc
index 13fce4a333..2f5ad3a4d1 100644
--- a/src/reader/wgsl/parser_impl_storage_class_test.cc
+++ b/src/reader/wgsl/parser_impl_storage_class_test.cc
@@ -50,8 +50,6 @@ INSTANTIATE_TEST_SUITE_P(
         StorageClassData{"out", ast::StorageClass::kOutput},
         StorageClassData{"uniform", ast::StorageClass::kUniform},
         StorageClassData{"workgroup", ast::StorageClass::kWorkgroup},
-        StorageClassData{"uniform_constant",
-                         ast::StorageClass::kUniformConstant},
         StorageClassData{"storage", ast::StorageClass::kStorage},
         StorageClassData{"storage_buffer", ast::StorageClass::kStorage},
         StorageClassData{"image", ast::StorageClass::kImage},
diff --git a/src/reader/wgsl/parser_impl_variable_storage_decoration_test.cc b/src/reader/wgsl/parser_impl_variable_storage_decoration_test.cc
index a015b332e9..889f631782 100644
--- a/src/reader/wgsl/parser_impl_variable_storage_decoration_test.cc
+++ b/src/reader/wgsl/parser_impl_variable_storage_decoration_test.cc
@@ -52,8 +52,6 @@ INSTANTIATE_TEST_SUITE_P(
         VariableStorageData{"out", ast::StorageClass::kOutput},
         VariableStorageData{"uniform", ast::StorageClass::kUniform},
         VariableStorageData{"workgroup", ast::StorageClass::kWorkgroup},
-        VariableStorageData{"uniform_constant",
-                            ast::StorageClass::kUniformConstant},
         VariableStorageData{"storage", ast::StorageClass::kStorage},
         VariableStorageData{"storage_buffer", ast::StorageClass::kStorage},
         VariableStorageData{"image", ast::StorageClass::kImage},
diff --git a/src/reader/wgsl/token.cc b/src/reader/wgsl/token.cc
index 9f8b28d5c6..cf28d6e57f 100644
--- a/src/reader/wgsl/token.cc
+++ b/src/reader/wgsl/token.cc
@@ -297,8 +297,6 @@ std::string Token::TypeToName(Type type) {
       return "u32";
     case Token::Type::kUniform:
       return "uniform";
-    case Token::Type::kUniformConstant:
-      return "uniform_constant";
     case Token::Type::kVar:
       return "var";
     case Token::Type::kVec2:
diff --git a/src/reader/wgsl/token.h b/src/reader/wgsl/token.h
index 13e582e890..e7de5daf57 100644
--- a/src/reader/wgsl/token.h
+++ b/src/reader/wgsl/token.h
@@ -305,8 +305,6 @@ class Token {
     kU32,
     /// A 'uniform'
     kUniform,
-    /// A 'uniform_constant'
-    kUniformConstant,
     /// A 'var'
     kVar,
     /// A 'vec2'
@@ -664,8 +662,6 @@ class Token {
   bool IsU32() const { return type_ == Type::kU32; }
   /// @returns true if token is a 'uniform'
   bool IsUniform() const { return type_ == Type::kUniform; }
-  /// @returns true if token is a 'uniform_constant'
-  bool IsUniformConstant() const { return type_ == Type::kUniformConstant; }
   /// @returns true if token is a 'var'
   bool IsVar() const { return type_ == Type::kVar; }
   /// @returns true if token is a 'vec2'