Changeset 191110 in webkit for trunk/Source/JavaScriptCore/parser/Parser.cpp

Timestamp:

Oct 15, 2015, 7:35:12 AM (10 years ago)

Author:

Yusuke Suzuki

Message:

[ES6] Class expression should have lexical environment that has itself as an imutable binding
​https://bugs.webkit.org/show_bug.cgi?id=150089

Reviewed by Geoffrey Garen.

According to ES6 spec, class expression has its own lexical environment that holds itself
as an immutable binding[1] (section 14.5.14 step 2, 3, 4, 23)

As a result, even if the binding declared in the outer scope is overridden, methods inside
class expression can refer its class by the class name.

[1]: ​http://ecma-international.org/ecma-262/6.0/#sec-runtime-semantics-classdefinitionevaluation

• bytecompiler/NodesCodegen.cpp:

(JSC::ClassExprNode::emitBytecode):

• parser/ASTBuilder.h:

(JSC::ASTBuilder::createClassExpr):

• parser/NodeConstructors.h:

(JSC::ClassExprNode::ClassExprNode):

• parser/Nodes.h:
• parser/Parser.cpp:

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

• parser/SyntaxChecker.h:

(JSC::SyntaxChecker::createClassExpr):

• tests/es6.yaml:
• tests/stress/class-expression-generates-environment.js: Added.

(shouldBe):
(shouldThrow):
(prototype.method):
(staticMethod):
(A.prototype.method):
(A.staticMethod):
(A):

• tests/stress/class-expression-should-be-tdz-in-heritage.js: Added.

(shouldThrow):
(shouldThrow.A):

File:

• trunk/Source/JavaScriptCore/parser/Parser.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/parser/Parser.cpp

@@ -1924 +1924 @@
 
     AutoPopScopeRef classScope(this, pushScope());
+    classScope->setIsLexicalScope();
+    classScope->preventVarDeclarations();
     classScope->setStrictMode();
 
@@ -1931 +1933 @@
         info.className = className;
         next();
-        failIfTrue(classScope->declareVariable(className) & DeclarationResult::InvalidStrictMode, "'", className->impl(), "' is not a valid class name");
+        failIfTrue(classScope->declareLexicalVariable(className, true) & DeclarationResult::InvalidStrictMode, "'", className->impl(), "' is not a valid class name");
     } else if (requirements == FunctionNeedsName) {
         if (match(OPENBRACE))
@@ -2047 +2049 @@
     }
 
+    consumeOrFail(CLOSEBRACE, "Expected a closing '}' after a class body");
+
+    auto classExpression = context.createClassExpr(location, *className, classScope->finalizeLexicalEnvironment(), constructor, parentClass, instanceMethods, staticMethods);
     popScope(classScope, TreeBuilder::NeedsFreeVariableInfo);
-    consumeOrFail(CLOSEBRACE, "Expected a closing '}' after a class body");
-
-    return context.createClassExpr(location, *className, constructor, parentClass, instanceMethods, staticMethods);
+    return classExpression;
 }
 #endif