Ambiguous references do not necessarily cause compilation errors (issue 5736).

runtime/vm/class_finalizer.h

 // 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.
 
 #ifndef VM_CLASS_FINALIZER_H_
 #define VM_CLASS_FINALIZER_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 
@@ skipping 31 matching lines @@
                                // type is not tolerated.
   };
 
   // Finalize given type while parsing class cls.
   // Also canonicalize type if applicable.
   static RawAbstractType* FinalizeType(const Class& cls,
                                        const AbstractType& type,
                                        FinalizationKind finalization);
 
   // Allocate, finalize, and return a new malformed type as if it was declared
-  // in class cls at the given token position. Build the error message from the
-  // format string and its arguments.
-  static RawType* NewFinalizedMalformedType(const Class& cls,
+  // in class cls at the given token position.
+  // If not null, prepend prev_error to the error message built from the format
+  // string and its arguments.
+  static RawType* NewFinalizedMalformedType(const Error& prev_error,
+                                            const Class& cls,
                                             intptr_t type_pos,
+                                            FinalizationKind finalization,
                                             const char* format, ...)
-       PRINTF_ATTRIBUTE(3, 4);
+       PRINTF_ATTRIBUTE(5, 6);
 
   // Depending on the given type, finalization mode, and execution mode, mark
   // the given type as malformed or report a compile time error.
   // If not null, prepend prev_error to the error message built from the format
   // string and its arguments.
   static void FinalizeMalformedType(const Error& prev_error,
                                     const Class& cls,
                                     const Type& type,
                                     FinalizationKind finalization,
                                     const char* format, ...)
@@ skipping 52 matching lines @@
   static void ReportError(const Error& error);
   static void ReportError(const Script& script,
                           intptr_t token_index,
                           const char* format, ...) PRINTF_ATTRIBUTE(3, 4);
   static void ReportError(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
 };
 
 }  // namespace dart
 
 #endif  // VM_CLASS_FINALIZER_H_