[parser] Improve error when using import decl in a script

Perform a best-effort check for module context and provide an
appropriate error.

As seen from the import-blah-script.js test, we could have invalid
import expressions in a script context that could result in an error
saying "Cannot use import statement outside a module" which isn't
the ideal error because the error is an incorrect import
expression.

But, when the developer changes to a module context, the
correct error is thrown.

To fix this, we'd have to refactor and call ParseImportDeclaration,
and then throw an appropriate error, which seems like a lot of
overhead for not enough gain.

Bug: v8:9392, v8:6513
Change-Id: I520ebb490fff4d95743a7c751d4095db9a35d41b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1675948Reviewed-by: Mythri Alle <mythria@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62358}

src/execution/message-template.h

@@ -90,6 +90,7 @@ namespace internal {
   T(ImmutablePrototypeSet,                                                     \
     "Immutable prototype object '%' cannot have their prototype set")          \
   T(ImportCallNotNewExpression, "Cannot use new with import")                  \
+  T(ImportOutsideModule, "Cannot use import statement outside a module")       \
   T(ImportMetaOutsideModule, "Cannot use 'import.meta' outside a module")      \
   T(ImportMissingSpecifier, "import() requires a specifier")                   \
   T(IncompatibleMethodReceiver, "Method % called on incompatible receiver %")  \

src/parsing/parser-base.h

@@ -3296,7 +3296,18 @@ ParserBase<Impl>::ParseImportExpressions() {
 
     return impl()->ImportMetaExpression(pos);
   }
-  Expect(Token::LPAREN);
+
+  if (V8_UNLIKELY(peek() != Token::LPAREN)) {
+    if (!parsing_module_) {
+      impl()->ReportMessageAt(scanner()->location(),
+                              MessageTemplate::kImportOutsideModule);
+    } else {
+      ReportUnexpectedToken(Next());
+    }
+    return impl()->FailureExpression();
+  }
+
+  Consume(Token::LPAREN);
   if (peek() == Token::RPAREN) {
     impl()->ReportMessageAt(scanner()->location(),
                             MessageTemplate::kImportMissingSpecifier);

test/cctest/interpreter/bytecode_expectations/AsyncGenerators.golden

@@ -301,7 +301,7 @@ bytecodes: [
                 B(Mov), R(context), R(18),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(19),
                 B(LdaConstant), U8(12),
                 B(Star), R(20),

test/cctest/interpreter/bytecode_expectations/DestructuringAssignment.golden

@@ -67,7 +67,7 @@ bytecodes: [
                 B(Mov), R(context), R(13),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(14),
                 B(LdaConstant), U8(6),
                 B(Star), R(15),
@@ -204,7 +204,7 @@ bytecodes: [
                 B(Mov), R(context), R(14),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(15),
                 B(LdaConstant), U8(6),
                 B(Star), R(16),
@@ -328,7 +328,7 @@ bytecodes: [
                 B(Mov), R(context), R(15),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(16),
                 B(LdaConstant), U8(7),
                 B(Star), R(17),

test/cctest/interpreter/bytecode_expectations/ForAwaitOf.golden

@@ -95,7 +95,7 @@ bytecodes: [
                 B(Mov), R(context), R(17),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(18),
                 B(LdaConstant), U8(9),
                 B(Star), R(19),
@@ -264,7 +264,7 @@ bytecodes: [
                 B(Mov), R(context), R(17),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(18),
                 B(LdaConstant), U8(9),
                 B(Star), R(19),
@@ -449,7 +449,7 @@ bytecodes: [
                 B(Mov), R(context), R(17),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(18),
                 B(LdaConstant), U8(9),
                 B(Star), R(19),
@@ -601,7 +601,7 @@ bytecodes: [
                 B(Mov), R(context), R(14),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(15),
                 B(LdaConstant), U8(8),
                 B(Star), R(16),

test/cctest/interpreter/bytecode_expectations/ForOf.golden

@@ -63,7 +63,7 @@ bytecodes: [
                 B(Mov), R(context), R(12),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(13),
                 B(LdaConstant), U8(6),
                 B(Star), R(14),
@@ -166,7 +166,7 @@ bytecodes: [
                 B(Mov), R(context), R(13),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(14),
                 B(LdaConstant), U8(6),
                 B(Star), R(15),
@@ -279,7 +279,7 @@ bytecodes: [
                 B(Mov), R(context), R(12),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(13),
                 B(LdaConstant), U8(6),
                 B(Star), R(14),
@@ -385,7 +385,7 @@ bytecodes: [
                 B(Mov), R(context), R(12),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(13),
                 B(LdaConstant), U8(8),
                 B(Star), R(14),

test/cctest/interpreter/bytecode_expectations/ForOfLoop.golden

@@ -67,7 +67,7 @@ bytecodes: [
                 B(Mov), R(context), R(14),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(15),
                 B(LdaConstant), U8(5),
                 B(Star), R(16),
@@ -204,7 +204,7 @@ bytecodes: [
                 B(Mov), R(context), R(15),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(16),
                 B(LdaConstant), U8(10),
                 B(Star), R(17),
@@ -319,7 +319,7 @@ bytecodes: [
                 B(Mov), R(context), R(13),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(14),
                 B(LdaConstant), U8(7),
                 B(Star), R(15),
@@ -431,7 +431,7 @@ bytecodes: [
                 B(Mov), R(context), R(16),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(17),
                 B(LdaConstant), U8(7),
                 B(Star), R(18),
@@ -548,7 +548,7 @@ bytecodes: [
                 B(Mov), R(context), R(15),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(16),
                 B(LdaConstant), U8(8),
                 B(Star), R(17),
@@ -680,7 +680,7 @@ bytecodes: [
                 B(Mov), R(context), R(14),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(15),
                 B(LdaConstant), U8(11),
                 B(Star), R(16),
@@ -796,7 +796,7 @@ bytecodes: [
                 B(Mov), R(context), R(16),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(17),
                 B(LdaConstant), U8(5),
                 B(Star), R(18),
@@ -936,7 +936,7 @@ bytecodes: [
                 B(Mov), R(context), R(15),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(16),
                 B(LdaConstant), U8(6),
                 B(Star), R(17),

test/cctest/interpreter/bytecode_expectations/Generators.golden

@@ -181,7 +181,7 @@ bytecodes: [
                 B(Mov), R(context), R(14),
                 B(TestTypeOf), U8(6),
                 B(JumpIfTrue), U8(18),
-                B(Wide), B(LdaSmi), I16(158),
+                B(Wide), B(LdaSmi), I16(159),
                 B(Star), R(15),
                 B(LdaConstant), U8(12),
                 B(Star), R(16),

test/message/fail/import-blah-module.js

+// Copyright 2019 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// MODULE
+
+(import{blah})

test/message/fail/import-blah-module.out

+# Copyright 2019 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+*%(basename)s:7: SyntaxError: Unexpected token '{'
+(import{blah})
+       ^
+SyntaxError: Unexpected token '{'

test/message/fail/import-blah-script.js

+// Copyright 2019 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+(import{blah})

test/message/fail/import-blah-script.out

+# Copyright 2019 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+*%(basename)s:5: SyntaxError: Cannot use import statement outside a module
+(import{blah})
+ ^^^^^^
+SyntaxError: Cannot use import statement outside a module

test/message/fail/import-script.js

+// Copyright 2019 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+import { test } from "mod";

test/message/fail/import-script.out

+# Copyright 2019 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+*%(basename)s:6: SyntaxError: Cannot use import statement outside a module
+import { test } from "mod";
+^^^^^^
+SyntaxError: Cannot use import statement outside a module
\ No newline at end of file