Add javascript compatibility warnings for strings that are not identical, but

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 "platform/utils.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
@@ skipping 24 matching lines @@
 namespace dart {
 
 DEFINE_FLAG(bool, enable_asserts, false, "Enable assert statements.");
 DEFINE_FLAG(bool, enable_type_checks, false, "Enable type checks.");
 DEFINE_FLAG(bool, trace_parser, false, "Trace parser operations.");
 DEFINE_FLAG(bool, warning_as_error, false, "Treat warnings as errors.");
 DEFINE_FLAG(bool, silent_warnings, false, "Silence warnings.");
 DEFINE_FLAG(bool, warn_mixin_typedef, true, "Warning on legacy mixin typedef.");
 DECLARE_FLAG(bool, error_on_bad_type);
 DECLARE_FLAG(bool, throw_on_javascript_int_overflow);
+DECLARE_FLAG(bool, warn_on_javascript_compatibility);
 
 static void CheckedModeHandler(bool value) {
   FLAG_enable_asserts = value;
   FLAG_enable_type_checks = value;
 }
 
 // --enable-checked-mode and --checked both enable checked mode which is
 // equivalent to setting --enable-asserts and --enable-type-checks.
 DEFINE_FLAG_HANDLER(CheckedModeHandler,
                     enable_checked_mode,
@@ skipping 8316 matching lines @@
     return ThrowNoSuchMethodError(ident_pos,
                                   cls,
                                   func_name,
                                   arguments,
                                   InvocationMirror::kStatic,
                                   InvocationMirror::kMethod,
                                   NULL);  // No existing function.
   } else if (cls.IsTopLevel() &&
       (cls.library() == Library::CoreLibrary()) &&
       (func.name() == Symbols::Identical().raw())) {
-    // This is the predefined toplevel function identical(a,b). Create
-    // a comparison node instead.
-    ASSERT(num_arguments == 2);
-    return new(isolate()) ComparisonNode(ident_pos,
-                                         Token::kEQ_STRICT,
-                                         arguments->NodeAt(0),
-                                         arguments->NodeAt(1));
+    // This is the predefined toplevel function identical(a,b).
+    // Create a comparison node instead of a static call to the function, unless
+    // javascript warnings are desired and identical is not invoked from a patch
+    // source.
+    if (!FLAG_warn_on_javascript_compatibility || is_patch_source()) {
+      ASSERT(num_arguments == 2);
+      return new(isolate()) ComparisonNode(ident_pos,
+                                           Token::kEQ_STRICT,
+                                           arguments->NodeAt(0),
+                                           arguments->NodeAt(1));
+    }
   }
   return new(isolate()) StaticCallNode(call_pos, func, arguments);
 }
 
 
 AstNode* Parser::ParseInstanceCall(AstNode* receiver, const String& func_name) {
   TRACE_PARSER("ParseInstanceCall");
   const intptr_t call_pos = TokenPos();
   CheckToken(Token::kLPAREN);
   ArgumentListNode* arguments = ParseActualParameters(NULL, kAllowConst);
@@ skipping 2629 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart