Changeset 187680 in webkit for trunk/Source/JavaScriptCore/parser/Parser.cpp

Timestamp:

Jul 31, 2015, 2:05:19 PM (10 years ago)

Author:

[email protected]

Message:

ES6 class syntax should use block scoping
​https://bugs.webkit.org/show_bug.cgi?id=142567

Reviewed by Geoffrey Garen.

Source/JavaScriptCore:

We treat class declarations like we do "let" declarations.
The class name is under TDZ until the class declaration
statement is evaluated. Class declarations also follow
the same rules as "let": No duplicate definitions inside
a lexical environment.

• parser/ASTBuilder.h:

(JSC::ASTBuilder::createClassDeclStatement):

• parser/Parser.cpp:

(JSC::Parser<LexerType>::parseClassDeclaration):

• tests/stress/class-syntax-block-scoping.js: Added.

(assert):
(truth):
(.):

• tests/stress/class-syntax-definition-semantics.js: Added.

(shouldBeSyntaxError):
(shouldNotBeSyntaxError):
(truth):

• tests/stress/class-syntax-tdz.js:

(assert):
(shouldThrowTDZ):
(truth):
(.):

LayoutTests:

• js/class-constructor-return-expected.txt:
• js/class-syntax-call-expected.txt:
• js/class-syntax-declaration-expected.txt:
• js/class-syntax-default-constructor-expected.txt:
• js/class-syntax-extends-expected.txt:
• js/class-syntax-name-expected.txt:
• js/class-syntax-super-expected.txt:
• js/script-tests/class-constructor-return.js:

(shouldThrow):
(shouldNotThrow):
(shouldBeTrue):
(shouldBeFalse):

• js/script-tests/class-syntax-call.js:

(A):
(B):
(shouldThrow):
(shouldNotThrow):

• js/script-tests/class-syntax-declaration.js:

(shouldThrow):
(shouldNotThrow):
(shouldBe):

• js/script-tests/class-syntax-default-constructor.js:

(shouldThrow):
(shouldBe):
(shouldBeTrue):
(assert):
(A):
(B):

• js/script-tests/class-syntax-extends.js:

(shouldThrow):
(shouldNotThrow):
(shouldBe):
(shouldBeTrue):
(Base):
(Base.prototype.baseMethod):

• js/script-tests/class-syntax-name.js:

(shouldThrow):
(shouldNotThrow):
(shouldBe):
(shouldBeTrue):
(runTestShouldBe):

• js/script-tests/class-syntax-super.js:

(shouldThrow):
(shouldNotThrow):
(shouldBe):
(shouldBeTrue):
(shouldBeFalse):

File:

• trunk/Source/JavaScriptCore/parser/Parser.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/parser/Parser.cpp

@@ -1822 +1822 @@
     TreeClassExpression classExpr = parseClass(context, FunctionNeedsName, info);
     failIfFalse(classExpr, "Failed to parse class");
-    // FIXME: This should be like `let`, not `var`.
-    declareVariable(info.className);
+
+    DeclarationResultMask declarationResult = declareVariable(info.className, DeclarationType::LetDeclaration);
+    if (declarationResult & DeclarationResult::InvalidDuplicateDeclaration)
+        internalFailWithMessage(false, "Cannot declare a class twice: '", info.className->impl(), "'");
 
     JSTextPosition classEnd = lastTokenEndPosition();