diff --git a/BUILD.gn b/BUILD.gn
index 103c94169b..0e5ccc1681 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -914,6 +914,7 @@ source_set("tint_unittests_wgsl_reader_src") {
     "src/reader/wgsl/parser_impl_else_stmt_test.cc",
     "src/reader/wgsl/parser_impl_elseif_stmt_test.cc",
     "src/reader/wgsl/parser_impl_equality_expression_test.cc",
+    "src/reader/wgsl/parser_impl_error_msg_test.cc",
     "src/reader/wgsl/parser_impl_exclusive_or_expression_test.cc",
     "src/reader/wgsl/parser_impl_for_stmt_test.cc",
     "src/reader/wgsl/parser_impl_function_decl_test.cc",
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 7a04fc7333..95f4160baf 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -450,6 +450,7 @@ if(${TINT_BUILD_WGSL_READER})
     reader/wgsl/parser_impl_else_stmt_test.cc
     reader/wgsl/parser_impl_elseif_stmt_test.cc
     reader/wgsl/parser_impl_equality_expression_test.cc
+    reader/wgsl/parser_impl_error_msg_test.cc
     reader/wgsl/parser_impl_exclusive_or_expression_test.cc
     reader/wgsl/parser_impl_for_stmt_test.cc
     reader/wgsl/parser_impl_function_decl_test.cc
diff --git a/src/reader/wgsl/parser_impl_error_msg_test.cc b/src/reader/wgsl/parser_impl_error_msg_test.cc
new file mode 100644
index 0000000000..075f6562f6
--- /dev/null
+++ b/src/reader/wgsl/parser_impl_error_msg_test.cc
@@ -0,0 +1,784 @@
+// Copyright 2020 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "gtest/gtest.h"
+#include "src/reader/wgsl/parser_impl.h"
+#include "src/reader/wgsl/parser_impl_test_helper.h"
+
+namespace tint {
+namespace reader {
+namespace wgsl {
+namespace {
+
+class ParserImplErrorTest : public ParserImplTest {
+ public:
+  void expect(const char* source, const char* expected) {
+    auto* p = parser(source);
+    EXPECT_EQ(p->Parse(), false);
+    EXPECT_EQ(p->has_error(), true);
+    EXPECT_EQ(p->error(), expected);
+  }
+};
+
+TEST_F(ParserImplErrorTest, AdditiveInvalidExpr) {
+  expect("fn f() -> void { return 1.0 + <; }",
+         "1:31: unable to parse right side of + expression");
+}
+
+TEST_F(ParserImplErrorTest, AndInvalidExpr) {
+  expect("fn f() -> void { return 1 & >; }",
+         "1:29: unable to parse right side of & expression");
+}
+
+TEST_F(ParserImplErrorTest, ArrayIndexExprInvalidExpr) {
+  expect("fn f() -> void { x = y[^]; }",
+         "1:24: unable to parse expression inside []");
+}
+
+TEST_F(ParserImplErrorTest, ArrayIndexExprMissingRBracket) {
+  expect("fn f() -> void { x = y[1; }", "1:25: missing ] for array accessor");
+}
+
+TEST_F(ParserImplErrorTest, AssignmentStmtMissingAssignment) {
+  expect("fn f() -> void { a; }", "1:19: missing = for assignment");
+}
+
+TEST_F(ParserImplErrorTest, AssignmentStmtMissingAssignment2) {
+  expect("fn f() -> void { a : i32; }", "1:20: missing = for assignment");
+}
+
+TEST_F(ParserImplErrorTest, AssignmentStmtMissingSemicolon) {
+  expect("fn f() -> void { a = 1 }", "1:24: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, AssignmentStmtInvalidRHS) {
+  expect("fn f() -> void { a = >; }",
+         "1:22: unable to parse right side of assignment");
+}
+
+TEST_F(ParserImplErrorTest, BitcastExprMissingLessThan) {
+  expect("fn f() -> void { x = bitcast(y); }",
+         "1:29: missing < for bitcast expression");
+}
+
+TEST_F(ParserImplErrorTest, BitcastExprMissingGreaterThan) {
+  expect("fn f() -> void { x = bitcast<u32(y); }",
+         "1:33: missing > for bitcast expression");
+}
+
+TEST_F(ParserImplErrorTest, BitcastExprMissingType) {
+  expect("fn f() -> void { x = bitcast<>(y); }",
+         "1:30: missing type for bitcast expression");
+}
+
+TEST_F(ParserImplErrorTest, BreakStmtMissingSemicolon) {
+  expect("fn f() -> void { loop { break } }", "1:31: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, CallExprMissingRParen) {
+  expect("fn f() -> void { x = f(1.; }", "1:26: missing ) for call expression");
+}
+
+TEST_F(ParserImplErrorTest, CallStmtMissingRParen) {
+  expect("fn f() -> void { f(1.; }", "1:22: missing ) for call statement");
+}
+
+TEST_F(ParserImplErrorTest, CallStmtInvalidArgument0) {
+  expect("fn f() -> void { f(<); }",
+         "1:20: unable to parse argument expression");
+}
+
+TEST_F(ParserImplErrorTest, CallStmtInvalidArgument1) {
+  expect("fn f() -> void { f(1.0, <); }",
+         "1:25: unable to parse argument expression after comma");
+}
+
+TEST_F(ParserImplErrorTest, CallStmtMissingSemicolon) {
+  expect("fn f() -> void { f() }", "1:22: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, ConstructorExprMissingLParen) {
+  expect("fn f() -> void { x = vec2<u32>1,2); }",
+         "1:31: missing ( for type constructor");
+}
+
+TEST_F(ParserImplErrorTest, ConstructorExprMissingRParen) {
+  expect("fn f() -> void { x = vec2<u32>(1,2; }",
+         "1:35: missing ) for type constructor");
+}
+
+TEST_F(ParserImplErrorTest, ConstVarStmtInvalid) {
+  expect("fn f() -> void { const >; }",
+         "1:24: unable to parse variable declaration");
+}
+
+TEST_F(ParserImplErrorTest, ConstVarStmtMissingAssignment) {
+  expect("fn f() -> void { const a : i32; }",
+         "1:31: missing = for constant declaration");
+}
+
+TEST_F(ParserImplErrorTest, ConstVarStmtMissingConstructor) {
+  expect("fn f() -> void { const a : i32 = >; }",
+         "1:34: missing constructor for const declaration");
+}
+
+TEST_F(ParserImplErrorTest, ContinueStmtMissingSemicolon) {
+  expect("fn f() -> void { loop { continue } }", "1:34: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, DiscardStmtMissingSemicolon) {
+  expect("fn f() -> void { discard }", "1:26: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, EqualityInvalidExpr) {
+  expect("fn f() -> void { return 1 == >; }",
+         "1:30: unable to parse right side of == expression");
+}
+
+TEST_F(ParserImplErrorTest, ForLoopInitializerMissingSemicolon) {
+  expect("fn f() -> void { for (var i : i32 = 0 i < 8; i=i+1) {} }",
+         "1:39: missing ';' after initializer in for loop");
+}
+
+TEST_F(ParserImplErrorTest, ForLoopConditionMissingSemicolon) {
+  expect("fn f() -> void { for (var i : i32 = 0; i < 8 i=i+1) {} }",
+         "1:46: missing ';' after condition in for loop");
+}
+
+TEST_F(ParserImplErrorTest, ForLoopMissingLParen) {
+  expect("fn f() -> void { for var i : i32 = 0; i < 8; i=i+1) {} }",
+         "1:22: missing for loop (");
+}
+
+TEST_F(ParserImplErrorTest, ForLoopMissingRParen) {
+  expect("fn f() -> void { for (var i : i32 = 0; i < 8; i=i+1 {} }",
+         "1:53: missing for loop )");
+}
+
+TEST_F(ParserImplErrorTest, ForLoopMissingLBrace) {
+  expect("fn f() -> void { for (var i : i32 = 0; i < 8; i=i+1) } }",
+         "1:54: missing for loop {");
+}
+
+TEST_F(ParserImplErrorTest, ForLoopMissingRBrace) {
+  expect("fn f() -> void { for (var i : i32 = 0; i < 8; i=i+1) {",
+         "1:55: missing for loop }");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclInvalid) {
+  expect("[[stage(vertex)]] x;", "1:19: error parsing function declaration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoMissingEnd) {
+  expect("[[stage(vertex) fn f() -> void {}",
+         "1:17: missing ]] for function decorations");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoStageMissingLParen) {
+  expect("[[stage vertex]] fn f() -> void {}",
+         "1:9: missing ( for stage decoration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoStageMissingRParen) {
+  expect("[[stage(vertex]] fn f() -> void {}",
+         "1:15: missing ) for stage decoration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoStageInvalid) {
+  expect("[[stage(x)]] fn f() -> void {}",
+         "1:9: invalid value for stage decoration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeMissingLParen) {
+  expect("[[workgroup_size 1]] fn f() -> void {}",
+         "1:18: missing ( for workgroup_size");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeMissingRParen) {
+  expect("[[workgroup_size(1]] fn f() -> void {}",
+         "1:19: missing ) for workgroup_size");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeXInvalid) {
+  expect("[[workgroup_size(x)]] fn f() -> void {}",
+         "1:18: missing x value for workgroup_size");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeXNegative) {
+  expect("[[workgroup_size(-1)]] fn f() -> void {}",
+         "1:18: invalid value for workgroup_size x parameter");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeYInvalid) {
+  expect("[[workgroup_size(1, x)]] fn f() -> void {}",
+         "1:21: missing y value for workgroup_size");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeYNegative) {
+  expect("[[workgroup_size(1, -1)]] fn f() -> void {}",
+         "1:21: invalid value for workgroup_size y parameter");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeZInvalid) {
+  expect("[[workgroup_size(1, 2, x)]] fn f() -> void {}",
+         "1:24: missing z value for workgroup_size");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclDecoWorkgroupSizeZNegative) {
+  expect("[[workgroup_size(1, 2, -1)]] fn f() -> void {}",
+         "1:24: invalid value for workgroup_size z parameter");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclMissingIdentifier) {
+  expect("fn () -> void {}", "1:4: missing identifier for function");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclMissingLParen) {
+  expect("fn f) -> void {}", "1:5: missing ( for function declaration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclMissingRParen) {
+  expect("fn f( -> void {}", "1:7: missing ) for function declaration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclMissingArrow) {
+  expect("fn f() void {}", "1:8: missing -> for function declaration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclInvalidReturnType) {
+  expect("fn f() -> 1 {}", "1:11: unable to determine function return type");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclParamMissingColon) {
+  expect("fn f(x) -> void {}", "1:7: missing : for identifier declaration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclParamInvalidType) {
+  expect("fn f(x : 1) -> void {}",
+         "1:10: invalid type for identifier declaration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclParamMissing) {
+  expect("fn f(x : i32, ) -> void {}",
+         "1:13: found , but no variable declaration");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclMissingLBrace) {
+  expect("fn f() -> void }", "1:16: missing {");
+}
+
+TEST_F(ParserImplErrorTest, FunctionDeclMissingRBrace) {
+  expect("fn f() -> void {", "1:17: missing }");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstInvalidIdentifier) {
+  expect("const ^ : i32 = 1;",
+         "1:7: error parsing constant variable identifier");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstMissingSemicolon) {
+  expect("const i : i32 = 1", "1:18: missing ';' for constant declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstMissingLParen) {
+  expect("const i : vec2<i32> = vec2<i32>;",
+         "1:32: missing ( for type constructor");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstMissingRParen) {
+  expect("const i : vec2<i32> = vec2<i32>(1., 2.;",
+         "1:39: missing ) for type constructor");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstMissingAssignment) {
+  expect("const i : vec2<i32>;", "1:20: missing = for const declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstBadConstLiteral) {
+  expect("const i : vec2<i32> = vec2<i32>(!);",
+         "1:33: unable to parse const literal");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstExprMaxDepth) {
+  std::stringstream out;
+  out << "const i : i32 = ";
+  for (size_t i = 0; i < 200; i++) {
+    out << "f32(";
+  }
+  out << "1.0";
+  for (size_t i = 0; i < 200; i++) {
+    out << ")";
+  }
+  out << ";";
+  expect(out.str().c_str(), "1:533: max const_expr depth reached");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstExprMissingLParen) {
+  expect("const i : vec2<i32> = vec2<i32> 1, 2);",
+         "1:33: missing ( for type constructor");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclConstExprMissingRParen) {
+  expect("const i : vec2<i32> = vec2<i32>(1, 2;",
+         "1:37: missing ) for type constructor");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclSampledTextureMissingLessThan) {
+  expect("var x : texture_sampled_1d;",
+         "1:28: missing '<' for sampled texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclSampledTextureMissingGreaterThan) {
+  expect("var x : texture_sampled_1d<f32;",
+         "1:32: missing '>' for sampled texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclSampledTextureInvalidSubtype) {
+  expect("var x : texture_sampled_1d<1>;",
+         "1:28: invalid subtype for sampled texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclMultisampledTextureMissingLessThan) {
+  expect("var x : texture_multisampled_2d;",
+         "1:33: missing '<' for multisampled texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclMultisampledTextureMissingGreaterThan) {
+  expect("var x : texture_multisampled_2d<f32;",
+         "1:37: missing '>' for multisampled texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclMultisampledTextureInvalidSubtype) {
+  expect("var x : texture_multisampled_2d<1>;",
+         "1:33: invalid subtype for multisampled texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStorageTextureMissingLessThan) {
+  expect("var x : texture_ro_2d;",
+         "1:23: missing '<' for storage texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStorageTextureMissingGreaterThan) {
+  expect("var x : texture_ro_2d<r8uint;",
+         "1:30: missing '>' for storage texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStorageTextureMissingInvalidSubtype) {
+  expect("var x : texture_ro_2d<1>;",
+         "1:23: invalid format for storage texture type");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructDecoMissingStruct) {
+  expect("[[block]];", "1:10: missing struct declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructDecoMissingEnd) {
+  expect("[[block struct {};", "1:9: missing ]] for struct decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructDeclMissingIdentifier) {
+  expect("struct {};", "1:8: missing identifier for struct declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructDeclMissingSemicolon) {
+  expect("struct S {}", "1:12: missing ';' for struct declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructDeclMissingLBrace) {
+  expect("struct S };", "1:10: missing { for struct declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructDeclMissingRBrace) {
+  expect("struct S { i : i32;", "1:20: missing } for struct declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberDecoEmpty) {
+  expect("struct S { [[]] i : i32; };",
+         "1:14: empty struct member decoration found");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberDecoMissingEnd) {
+  expect("struct S { [[ i : i32; };",
+         "1:15: missing ]] for struct member decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberInvalidIdentifier) {
+  expect("struct S { 1 : i32; };", "1:12: invalid identifier declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberMissingSemicolon) {
+  expect("struct S { i : i32 };", "1:20: missing ; for struct member");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberOffsetMissingLParen) {
+  expect("struct S { [[offset 1)]] i : i32 };", "1:21: missing ( for offset");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberOffsetMissingRParen) {
+  expect("struct S { [[offset(1]] i : i32 };", "1:22: missing ) for offset");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberOffsetInvaldValue) {
+  expect("struct S { [[offset(x)]] i : i32 };",
+         "1:21: invalid value for offset decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclStructMemberOffsetNegativeValue) {
+  expect("struct S { [[offset(-2)]] i : i32 };",
+         "1:21: offset value must be >= 0");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclTypeAliasMissingIdentifier) {
+  expect("type 1 = f32;", "1:6: missing identifier for type alias");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclTypeAliasInvalidType) {
+  expect("type meow = 1;", "1:13: invalid type alias");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclTypeAliasMissingAssignment) {
+  expect("type meow f32", "1:11: missing = for type alias");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclTypeAliasMissingSemicolon) {
+  expect("type meow = f32", "1:16: missing ';' for type alias");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclTypeInvalid) {
+  expect("var x : fish;", "1:9: unknown constructed type 'fish'");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclTypeDecoInvalid) {
+  expect("var x : [[]] i32;", "1:9: invalid type for identifier declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayMissingLessThan) {
+  expect("var i : array;", "1:14: missing < for array declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayMissingGreaterThan) {
+  expect("var i : array<u32, 3;", "1:21: missing > for array declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayDecoNotArray) {
+  expect("var i : [[stride(1)]] i32;",
+         "1:23: found array decoration but no array");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayDecoMissingEnd) {
+  expect("var i : [[stride(1) array<i32>;",
+         "1:21: missing ]] for array decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayDecoStrideMissingLParen) {
+  expect("var i : [[stride 1)]] array<i32>;",
+         "1:18: missing ( for stride attribute");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayDecoStrideMissingRParen) {
+  expect("var i : [[stride(1]] array<i32>;",
+         "1:19: missing ) for stride attribute");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayDecoStrideInvalid) {
+  expect("var i : [[stride(x)]] array<i32>;",
+         "1:18: missing value for stride decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayDecoStrideNegative) {
+  expect("var i : [[stride(-1)]] array<i32>;",
+         "1:18: invalid stride value: -1");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayMissingType) {
+  expect("var i : array<1, 3>;", "1:15: invalid type for array declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayInvalidSize) {
+  expect("var i : array<u32, x>;", "1:20: missing size of array declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarArrayNegativeSize) {
+  expect("var i : array<u32, -3>;", "1:20: invalid size for array declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoListEmpty) {
+  expect("[[]] var i : i32;", "1:3: empty variable decoration list");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoListInvalid) {
+  expect("[[location(1), meow]] var i : i32;",
+         "1:16: missing variable decoration after comma");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoListMissingComma) {
+  expect("[[location(1) set(2)]] var i : i32;",
+         "1:15: missing comma in variable decoration list");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoListMissingEnd) {
+  expect("[[location(1) meow]] var i : i32;",
+         "1:15: missing ]] for variable decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoLocationMissingLParen) {
+  expect("[[location 1]] var i : i32;",
+         "1:12: missing ( for location decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoLocationMissingRParen) {
+  expect("[[location (1]] var i : i32;",
+         "1:14: missing ) for location decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoLocationInvalidValue) {
+  expect("[[location(x)]] var i : i32;",
+         "1:12: invalid value for location decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBuiltinMissingLParen) {
+  expect("[[builtin position]] var i : i32;",
+         "1:11: missing ( for builtin decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBuiltinMissingRParen) {
+  expect("[[builtin(position]] var i : i32;",
+         "1:19: missing ) for builtin decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBuiltinInvalidIdentifer) {
+  expect("[[builtin(1)]] var i : i32;",
+         "1:11: expected identifier for builtin");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBuiltinInvalidValue) {
+  expect("[[builtin(x)]] var i : i32;",
+         "1:11: invalid value for builtin decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBindingMissingLParen) {
+  expect("[[binding 1]] var i : i32;",
+         "1:11: missing ( for binding decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBindingMissingRParen) {
+  expect("[[binding(1]] var i : i32;",
+         "1:12: missing ) for binding decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBindingInvalidValue) {
+  expect("[[binding(x)]] var i : i32;",
+         "1:11: invalid value for binding decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoSetMissingLParen) {
+  expect("[[set 1]] var i : i32;", "1:7: missing ( for set decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoSetMissingRParen) {
+  expect("[[set(1]] var i : i32;", "1:8: missing ) for set decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarDecoBindingSetValue) {
+  expect("[[set(x)]] var i : i32;", "1:7: invalid value for set decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarInvalidIdentifier) {
+  expect("var ^ : mat4x4;", "1:5: invalid identifier declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarMatrixMissingLessThan) {
+  expect("var i : mat4x4;", "1:15: missing < for matrix");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarMatrixMissingGreaterThan) {
+  expect("var i : mat4x4<u32;", "1:19: missing > for matrix");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarMatrixMissingType) {
+  expect("var i : mat4x4<1>;", "1:16: unable to determine subtype for matrix");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarMissingSemicolon) {
+  expect("var i : i32", "1:12: missing ';' for variable declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarPtrMissingLessThan) {
+  expect("var i : ptr;", "1:12: missing < for ptr declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarPtrMissingGreaterThan) {
+  expect("var i : ptr<in, u32;", "1:20: missing > for ptr declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarPtrMissingComma) {
+  expect("var i : ptr<in u32>;", "1:16: missing , for ptr declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarPtrMissingStorageClass) {
+  expect("var i : ptr<meow, u32>;",
+         "1:13: missing storage class for ptr declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarPtrMissingType) {
+  expect("var i : ptr<in, 1>;", "1:17: missing type for ptr declaration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarStorageDeclInvalidClass) {
+  expect("var<fish> i : i32",
+         "1:5: invalid storage class for variable decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarStorageDeclMissingGThan) {
+  expect("var<in i : i32", "1:8: missing > for variable decoration");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarVectorMissingLessThan) {
+  expect("var i : vec3;", "1:13: missing < for vector");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarVectorMissingGreaterThan) {
+  expect("var i : vec3<u32;", "1:17: missing > for vector");
+}
+
+TEST_F(ParserImplErrorTest, GlobalDeclVarVectorMissingType) {
+  expect("var i : vec3<1>;", "1:14: unable to determine subtype for vector");
+}
+
+TEST_F(ParserImplErrorTest, IfStmtMissingLParen) {
+  expect("fn f() -> void { if true) {} }", "1:21: expected (");
+}
+
+TEST_F(ParserImplErrorTest, IfStmtMissingRParen) {
+  expect("fn f() -> void { if (true {} }", "1:27: expected )");
+}
+
+TEST_F(ParserImplErrorTest, IfStmtInvalidCond) {
+  expect("fn f() -> void { if (>) {} }", "1:22: unable to parse expression");
+}
+
+TEST_F(ParserImplErrorTest, LogicalAndInvalidExpr) {
+  expect("fn f() -> void { return 1 && >; }",
+         "1:30: unable to parse right side of && expression");
+}
+
+TEST_F(ParserImplErrorTest, LogicalOrInvalidExpr) {
+  expect("fn f() -> void { return 1 || >; }",
+         "1:30: unable to parse right side of || expression");
+}
+
+TEST_F(ParserImplErrorTest, LoopMissingLBrace) {
+  expect("fn f() -> void { loop } }", "1:23: missing { for loop");
+}
+
+TEST_F(ParserImplErrorTest, LoopMissingRBrace) {
+  expect("fn f() -> void { loop {", "1:24: missing } for loop");
+}
+
+TEST_F(ParserImplErrorTest, MemberExprMissingIdentifier) {
+  expect("fn f() -> void { x = a.; }",
+         "1:24: missing identifier for member accessor");
+}
+
+TEST_F(ParserImplErrorTest, MultiplicativeInvalidExpr) {
+  expect("fn f() -> void { return 1.0 * <; }",
+         "1:31: unable to parse right side of * expression");
+}
+
+TEST_F(ParserImplErrorTest, OrInvalidExpr) {
+  expect("fn f() -> void { return 1 | >; }",
+         "1:29: unable to parse right side of | expression");
+}
+
+TEST_F(ParserImplErrorTest, RelationalInvalidExpr) {
+  expect("fn f() -> void { return 1 < >; }",
+         "1:29: unable to parse right side of < expression");
+}
+
+TEST_F(ParserImplErrorTest, ReturnStmtMissingSemicolon) {
+  expect("fn f() -> void { return }", "1:25: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, ShiftInvalidExpr) {
+  expect("fn f() -> void { return 1 << >; }",
+         "1:30: unable to parse right side of << expression");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtMissingLBrace) {
+  expect("fn f() -> void { switch(1) }",
+         "1:28: missing { for switch statement");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtMissingRBrace) {
+  expect("fn f() -> void { switch(1) {",
+         "1:29: missing } for switch statement");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtInvalidCase) {
+  expect("fn f() -> void { switch(1) { case ^: } }",
+         "1:35: unable to parse case selectors");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtInvalidCase2) {
+  expect("fn f() -> void { switch(1) { case false: } }",
+         "1:35: invalid case selector must be an integer value");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtCaseMissingColon) {
+  expect("fn f() -> void { switch(1) { case 1 {} } }",
+         "1:37: missing : for case statement");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtCaseMissingLBrace) {
+  expect("fn f() -> void { switch(1) { case 1: } } }",
+         "1:38: missing { for case statement");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtCaseMissingRBrace) {
+  expect("fn f() -> void { switch(1) { case 1: {",
+         "1:39: missing } for case statement");
+}
+
+TEST_F(ParserImplErrorTest, SwitchStmtCaseFallthroughMissingSemicolon) {
+  expect("fn f() -> void { switch(1) { case 1: { fallthrough } case 2: {} } }",
+         "1:52: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, VarStmtMissingSemicolon) {
+  expect("fn f() -> void { var a : u32 }", "1:30: missing ;");
+}
+
+TEST_F(ParserImplErrorTest, VarStmtInvalidAssignment) {
+  expect("fn f() -> void { var a : u32 = >; }",
+         "1:32: missing constructor for variable declaration");
+}
+
+TEST_F(ParserImplErrorTest, UnaryInvalidExpr) {
+  expect("fn f() -> void { return !<; }",
+         "1:26: unable to parse right side of ! expression");
+}
+
+TEST_F(ParserImplErrorTest, UnexpectedToken) {
+  expect("unexpected", "1:1: invalid token (kIdentifier) encountered");
+}
+
+TEST_F(ParserImplErrorTest, XorInvalidExpr) {
+  expect("fn f() -> void { return 1 ^ >; }",
+         "1:29: unable to parse right side of ^ expression");
+}
+
+}  // namespace
+}  // namespace wgsl
+}  // namespace reader
+}  // namespace tint