Prevent mutation of final variables

runtime/vm/parser.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/parser.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/compiler_stats.h"
@@ skipping 6758 matching lines @@
             op_pos, op_kind, left_operand, right_operand);
       }
     }
     current_preced--;
   }
   return left_operand;
 }
 
 
 bool Parser::IsAssignableExpr(AstNode* expr) {
-  return (expr->IsLoadLocalNode() && !expr->AsLoadLocalNode()->HasPseudo())
+  return (expr->IsLoadLocalNode() && !expr->AsLoadLocalNode()->HasPseudo()
+          && (!expr->AsLoadLocalNode()->local().is_final()))
       || expr->IsLoadStaticFieldNode()
       || expr->IsStaticGetterNode()
       || expr->IsInstanceGetterNode()
       || expr->IsLoadIndexedNode()
       || (expr->IsPrimaryNode() && !expr->AsPrimaryNode()->IsSuper());
 }
 
 
 AstNode* Parser::ParseExprList() {
   TRACE_PARSER("ParseExprList");
@@ skipping 190 matching lines @@
 
 
 // Ensure that the expression temp is allocated for nodes that may need it.
 AstNode* Parser::CreateAssignmentNode(AstNode* original, AstNode* rhs) {
   AstNode* result = original->MakeAssignmentNode(rhs);
   if ((result == NULL) && original->IsStaticGetterNode()) {
     const String& setter_name = String::ZoneHandle(
         Field::SetterSymbol(original->AsStaticGetterNode()->field_name()));
     result = ThrowNoSuchMethodError(original->token_pos(), setter_name);
   }
+  // TODO(hausner): if we decide to throw a no such method error on
+  // assignment to a final variable, we need to do the same as in the
+  // StaticGetterNode above.
   if ((result != NULL) &&
       (result->IsStoreIndexedNode() ||
        result->IsInstanceSetterNode() ||
        result->IsStaticSetterNode() ||
        result->IsStoreStaticFieldNode() ||
        result->IsStoreLocalNode())) {
     EnsureExpressionTemp();
   }
   return result;
 }
@@ skipping 153 matching lines @@
     // Is prefix.
     AstNode* left_expr = PrepareCompoundAssignmentNodes(&expr);
     Token::Kind binary_op =
         (incr_op == Token::kINCR) ? Token::kADD : Token::kSUB;
     BinaryOpNode* add = new BinaryOpNode(
         op_pos,
         binary_op,
         expr,
         new LiteralNode(op_pos, Smi::ZoneHandle(Smi::New(1))));
     AstNode* store = CreateAssignmentNode(left_expr, add);
+    ASSERT(store != NULL);
     expr = store;
   } else {
     expr = ParsePostfixExpr();
   }
   return expr;
 }
 
 
 ArgumentListNode* Parser::ParseActualParameters(
                               ArgumentListNode* implicit_arguments,
@@ skipping 2690 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart