Infer whether a variable is assigned

src/preparser.h

 // 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.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/func-name-inferrer.h"
 #include "src/hashmap.h"
 #include "src/scopes.h"
@@ skipping 913 matching lines @@
   static void CheckFunctionLiteralInsideTopLevelObjectLiteral(
       PreParserScope* scope, PreParserExpression value, bool* has_function) {}
 
   static void CheckAssigningFunctionLiteralToProperty(
       PreParserExpression left, PreParserExpression right) {}
 
   // PreParser doesn't need to keep track of eval calls.
   static void CheckPossibleEvalCall(PreParserExpression expression,
                                     PreParserScope* scope) {}
 
-  static PreParserExpression MarkExpressionAsLValue(
+  static PreParserExpression MarkExpressionAsAssigned(
       PreParserExpression expression) {
     // TODO(marja): To be able to produce the same errors, the preparser needs
-    // to start tracking which expressions are variables and which are lvalues.
+    // to start tracking which expressions are variables and which are assigned.
     return expression;
   }
 
   bool ShortcutNumericLiteralBinaryExpression(PreParserExpression* x,
                                               PreParserExpression y,
                                               Token::Value op,
                                               int pos,
                                               PreParserFactory* factory) {
     return false;
   }
@@ skipping 756 matching lines @@
       this->ParseConditionalExpression(accept_IN, CHECK_OK);
 
   if (!Token::IsAssignmentOp(peek())) {
     if (fni_ != NULL) fni_->Leave();
     // Parsed conditional expression only (no assignment).
     return expression;
   }
 
   expression = this->CheckAndRewriteReferenceExpression(
       expression, lhs_location, "invalid_lhs_in_assignment", CHECK_OK);
-  expression = this->MarkExpressionAsLValue(expression);
+  expression = this->MarkExpressionAsAssigned(expression);
 
   Token::Value op = Next();  // Get assignment operator.
   int pos = position();
   ExpressionT right = this->ParseAssignmentExpression(accept_IN, CHECK_OK);
 
   // TODO(1231235): We try to estimate the set of properties set by
   // constructors. We define a new property whenever there is an
   // assignment to a property of 'this'. We should probably only add
   // properties if we haven't seen them before. Otherwise we'll
   // probably overestimate the number of properties.
@@ skipping 141 matching lines @@
     }
 
     // Allow Traits do rewrite the expression.
     return this->BuildUnaryExpression(expression, op, pos, factory());
   } else if (Token::IsCountOp(op)) {
     op = Next();
     Scanner::Location lhs_location = scanner()->peek_location();
     ExpressionT expression = this->ParseUnaryExpression(CHECK_OK);
     expression = this->CheckAndRewriteReferenceExpression(
         expression, lhs_location, "invalid_lhs_in_prefix_op", CHECK_OK);
-    this->MarkExpressionAsLValue(expression);
+    this->MarkExpressionAsAssigned(expression);
 
     return factory()->NewCountOperation(op,
                                         true /* prefix */,
                                         expression,
                                         position());
 
   } else {
     return this->ParsePostfixExpression(ok);
   }
 }
 
 
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
 ParserBase<Traits>::ParsePostfixExpression(bool* ok) {
   // PostfixExpression ::
   //   LeftHandSideExpression ('++' | '--')?
 
   Scanner::Location lhs_location = scanner()->peek_location();
   ExpressionT expression = this->ParseLeftHandSideExpression(CHECK_OK);
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       Token::IsCountOp(peek())) {
     expression = this->CheckAndRewriteReferenceExpression(
         expression, lhs_location, "invalid_lhs_in_postfix_op", CHECK_OK);
-    expression = this->MarkExpressionAsLValue(expression);
+    expression = this->MarkExpressionAsAssigned(expression);
 
     Token::Value next = Next();
     expression =
         factory()->NewCountOperation(next,
                                      false /* postfix */,
                                      expression,
                                      position());
   }
   return expression;
 }
@@ skipping 252 matching lines @@
       parser()->ReportMessage("accessor_get_set");
     }
     *ok = false;
   }
 }
 
 
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H