Compile time error on forward references to functions

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 "lib/invocation_mirror.h"
 #include "vm/bigint_operations.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
@@ skipping 5539 matching lines @@
     ASSERT(CurrentToken() == Token::kLPAREN);
     function_name = &Symbols::AnonymousClosure();
   } else {
     if (CurrentToken() == Token::kVOID) {
       ConsumeToken();
       result_type = Type::VoidType();
     } else if ((CurrentToken() == Token::kIDENT) &&
                (LookaheadToken(1) != Token::kLPAREN)) {
       result_type = ParseType(ClassFinalizer::kCanonicalize);
     }
+    intptr_t name_pos = TokenPos();

[srdjan, 2013/11/04 18:18:55]

const

[hausner, 2013/11/04 18:52:23]

Done.

     variable_name = ExpectIdentifier("function name expected");
     function_name = variable_name;
+
+    // Check that the function name has not been referenced
+    // before this declaration.
+    ASSERT(current_block_ != NULL);
+    const intptr_t previous_pos =
+        current_block_->scope->PreviousReferencePos(*function_name);
+    if (previous_pos >= 0) {
+      ASSERT(!script_.IsNull());
+      intptr_t line_number;
+      script_.GetTokenLocation(previous_pos, &line_number, NULL);
+      ErrorMsg(name_pos,
+               "identifier '%s' previously used in line %" Pd "",
+               function_name->ToCString(),
+               line_number);
+    }
   }
 
   if (CurrentToken() != Token::kLPAREN) {
     ErrorMsg("'(' expected");
   }
 
   // Check whether we have parsed this closure function before, in a previous
   // compilation. If so, reuse the function object, else create a new one
   // and register it in the current class.
   // Note that we cannot share the same closure function between the closurized
@@ skipping 5183 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart