Expose remaining 'errors' in an unified dart:core.

runtime/lib/error.dart

 // 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.
 // Errors are created and thrown by DartVM only.
 // Changes here should also be reflected in corelib/error.dart as well
 
-class AssertionErrorImplementation extends AssertionError {
+class AssertionErrorImplementation implements AssertionError {
   factory AssertionErrorImplementation._uninstantiable() {
     throw const UnsupportedOperationException(
         "AssertionError can only be allocated by the VM");
   }
   static _throwNew(int assertionStart, int assertionEnd)
       native "AssertionError_throwNew";
   String toString() {
     return "'$url': Failed assertion: line $line pos $column: "
         "'$failedAssertion' is not true.";
   }
   final String failedAssertion;
   final String url;
   final int line;
   final int column;
 }
 
-class TypeError extends AssertionErrorImplementation {
-  factory TypeError._uninstantiable() {
+class TypeErrorImplementation
+    extends AssertionErrorImplementation
+    implements TypeError {
+  factory TypeErrorImplementation._uninstantiable() {
     throw const UnsupportedOperationException(
         "TypeError can only be allocated by the VM");
   }
   static _throwNew(int location,
                    Object src_value,
                    String dst_type_name,
                    String dst_name,
                    String malformed_error)
       native "TypeError_throwNew";
   String toString() {
     String str = (malformedError != null) ? malformedError : "";
     if ((dstName != null) && (dstName.length > 0)) {
       str = "${str}type '$srcType' is not a subtype of "
             "type '$dstType' of '$dstName'.";
     } else {
       str = "${str}malformed type used.";
     }
     return str;
   }
   final String srcType;
   final String dstType;
   final String dstName;
   final String malformedError;
 }
 
-class CastException extends TypeError {
+class CastExceptionImplementation
+    extends TypeErrorImplementation
+    implements CastException {
   factory CastException._uninstantiable() {
     throw const UnsupportedOperationException(
         "CastException can only be allocated by the VM");
   }
   // A CastException is allocated by TypeError._throwNew() when dst_name equals
   // Exceptions::kCastExceptionDstName.
   String toString() {
     String str = (malformedError != null) ? malformedError : "";
     if ((dstName != null) && (dstName.length > 0)) {
       str = "${str}type '$srcType' is not a subtype of "
             "type '$dstType' in type cast.";
     } else {
       str = "${str}malformed type used in type cast.";
     }
     return str;
   }
 }
 
-class FallThroughError {
-  factory FallThroughError._uninstantiable() {
+class FallThroughErrorImplementation implements FallThroughError {
+  factory FallThroughErrorImplementation._uninstantiable() {
     throw const UnsupportedOperationException(
         "FallThroughError can only be allocated by the VM");
   }
   static _throwNew(int case_clause_pos) native "FallThroughError_throwNew";
   String toString() {
     return "'$url': Switch case fall-through at line $line.";
   }
   final String url;
   final int line;
 }
@@ skipping 14 matching lines @@
   String toString() => "Unresolved static method: url '$url' line $line "
       "pos $column\n$failedResolutionLine\n";
 
   static _throwNew(int token_pos) native "StaticResolutionException_throwNew";
 
   final String failedResolutionLine;
   final String url;
   final int line;
   final int column;
 }