Compute suggestions for failed type promotions.

sdk/lib/_internal/compiler/implementation/warnings.dart

 // 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.
 
 part of dart2js;
 
 const DONT_KNOW_HOW_TO_FIX = "";
 
 /**
  * The messages in this file should meet the following guide lines:
@@ skipping 1376 matching lines @@
       "promotion and potentially mutated in the scope of '#{variableName}'.");
 
   static const MessageKind ACCESSED_IN_CLOSURE_HERE = const MessageKind(
       "Info: Variable '#{variableName}' is accessed in a closure here.");
 
   static const MessageKind NOT_MORE_SPECIFIC = const MessageKind(
       "Hint: Variable '#{variableName}' is not shown to have type "
       "'#{shownType}' because '#{shownType}' is not more specific than the "
       "known type '#{knownType}' of '#{variableName}'.");
 
+  static const MessageKind NOT_MORE_SPECIFIC_SUBTYPE = const MessageKind(
+      "Hint: Variable '#{variableName}' is not shown to have type "
+      "'#{shownType}' because '#{shownType}' is not a subtype of the "
+      "known type '#{knownType}' of '#{variableName}'.");
+
+  static const MessageKind NOT_MORE_SPECIFIC_SUGGESTION = const MessageKind(
+      "Hint: Variable '#{variableName}' is not shown to have type "
+      "'#{shownType}' because '#{shownType}' is not more specific than the "
+      "known type '#{knownType}' of '#{variableName}'.",
+      howToFix: "Try replacing '#{shownType}' with '#{shownTypeSuggestion}'.");
+
   //////////////////////////////////////////////////////////////////////////////
   // Patch errors start.
   //////////////////////////////////////////////////////////////////////////////
 
   static const MessageKind PATCH_RETURN_TYPE_MISMATCH = const MessageKind(
       "Error: Patch return type '#{patchReturnType}' does not match "
       "'#{originReturnType}' on origin method '#{methodName}'.");
 
   static const MessageKind PATCH_REQUIRED_PARAMETER_COUNT_MISMATCH =
       const MessageKind(
@@ skipping 167 matching lines @@
 
 class CompileTimeConstantError extends Diagnostic {
   CompileTimeConstantError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }
 
 class CompilationError extends Diagnostic {
   CompilationError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }