Fix compilation warnings/errors seen with newer versions of gcc compiler.

runtime/vm/parser.cc

 // Copyright (c) 2011, 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 3645 matching lines @@
   }
   return if_node;
 }
 
 
 CaseNode* Parser::ParseCaseClause(LocalVariable* switch_expr_value,
                                   SourceLabel* case_label) {
   TRACE_PARSER("ParseCaseStatement");
   bool default_seen = false;
   intptr_t case_pos = token_index_;
-  intptr_t expr_pos = 0;
   SequenceNode* case_expressions =
       new SequenceNode(case_pos, current_block_->scope);
   while (CurrentToken() == Token::kCASE || CurrentToken() == Token::kDEFAULT) {
     if (CurrentToken() == Token::kCASE) {
       if (default_seen) {
         ErrorMsg("default clause must be last case");
       }
       ConsumeToken();  // Keyword case.
-      expr_pos = token_index_;
+      intptr_t expr_pos = token_index_;
       AstNode* expr = ParseExpr(kAllowConst);
       AstNode* switch_expr_load = new LoadLocalNode(case_pos,
                                                     *switch_expr_value);
-      AstNode* case_comparison = new ComparisonNode(case_pos,
+      AstNode* case_comparison = new ComparisonNode(expr_pos,
                                                     Token::kEQ,
                                                     expr,
                                                     switch_expr_load);
       case_expressions->Add(case_comparison);
     } else {
       if (default_seen) {
         ErrorMsg("only one default clause is allowed");
       }
       ConsumeToken();  // Keyword default.
-      expr_pos = token_index_;
       default_seen = true;
       // The default case always succeeds.
     }
     ExpectToken(Token::kCOLON);
   }
 
   OpenBlock();
   bool abrupt_completing_seen = false;
   while (true) {
     // Check whether the next statement still belongs to the current case
@@ skipping 3191 matching lines @@
 }
 
 
 void Parser::SkipNestedExpr() {
   const bool saved_mode = SetAllowFunctionLiterals(true);
   SkipExpr();
   SetAllowFunctionLiterals(saved_mode);
 }
 
 }  // namespace dart