Infer whether a variable is assigned

src/parser.cc

 // Copyright 2012 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.
 
 #include "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bootstrapper.h"
 #include "src/char-predicates-inl.h"
@@ skipping 434 matching lines @@
 void ParserTraits::CheckPossibleEvalCall(Expression* expression,
                                          Scope* scope) {
   VariableProxy* callee = expression->AsVariableProxy();
   if (callee != NULL &&
       callee->IsVariable(parser_->isolate()->factory()->eval_string())) {
     scope->DeclarationScope()->RecordEvalCall();
   }
 }
 
 
-Expression* ParserTraits::MarkExpressionAsLValue(Expression* expression) {
-  VariableProxy* proxy = expression != NULL
-      ? expression->AsVariableProxy()
-      : NULL;
-  if (proxy != NULL) proxy->MarkAsLValue();
+Expression* ParserTraits::MarkExpressionAsAssigned(Expression* expression) {
+  VariableProxy* proxy =
+      expression != NULL ? expression->AsVariableProxy() : NULL;
+  if (proxy != NULL) proxy->set_is_assigned();
   return expression;
 }
 
 
 bool ParserTraits::ShortcutNumericLiteralBinaryExpression(
     Expression** x, Expression* y, Token::Value op, int pos,
     AstNodeFactory<AstConstructionVisitor>* factory) {
   if ((*x)->AsLiteral() && (*x)->AsLiteral()->value()->IsNumber() &&
       y->AsLiteral() && y->AsLiteral()->value()->IsNumber()) {
     double x_val = (*x)->AsLiteral()->value()->Number();
@@ skipping 1238 matching lines @@
       if (allow_harmony_scoping() && strict_mode() == STRICT) {
         // In harmony we treat re-declarations as early errors. See
         // ES5 16 for a definition of early errors.
         ParserTraits::ReportMessage("var_redeclaration", name);
         *ok = false;
         return;
       }
       Expression* expression = NewThrowTypeError(
           "var_redeclaration", name, declaration->position());
       declaration_scope->SetIllegalRedeclaration(expression);
+    } else if (mode == VAR) {
+      var->set_maybe_assigned();
     }
   }
 
   // We add a declaration node for every declaration. The compiler
   // will only generate code if necessary. In particular, declarations
   // for inner local variables that do not represent functions won't
   // result in any generated code.
   //
   // Note that we always add an unresolved proxy even if it's not
   // used, simply because we don't know in this method (w/o extra
@@ skipping 3098 matching lines @@
       ASSERT(info()->isolate()->has_pending_exception());
     } else {
       result = ParseProgram();
     }
   }
   info()->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal