improve DDC's type checks

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/errors.dart

 // Copyright (c) 2015, 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 dart._runtime;
 
 // We need to set these properties while the sdk is only partially initialized
 // so we cannot use regular Dart fields.
 // The default values for these properties are set when the global_ final field
 // in runtime.dart is initialized.
 
 // Override, e.g., for testing
 void trapRuntimeErrors(bool flag) {
   JS('', 'dart.__trapRuntimeErrors = #', flag);
 }
 
 void ignoreWhitelistedErrors(bool flag) {
   JS('', 'dart.__ignoreWhitelistedErrors = #', flag);
 }
 
 void ignoreAllErrors(bool flag) {
   JS('', 'dart.__ignoreAllErrors = #', flag);
 }
 
-throwCastError(object, actual, type) {
-  var found = typeName(actual);
-  var expected = typeName(type);
-  if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
-  throw new CastErrorImplementation(object, found, expected);
-}
-
-throwTypeError(object, actual, type) {
-  var found = typeName(actual);
-  var expected = typeName(type);
-  if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
-  throw new TypeErrorImplementation(object, found, expected);
-}
-
-throwStrongModeCastError(object, actual, type) {
-  var found = typeName(actual);
-  var expected = typeName(type);
-  if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
-  throw new StrongModeCastError(object, found, expected);
-}
-
-throwStrongModeTypeError(object, actual, type) {
-  var found = typeName(actual);
-  var expected = typeName(type);
-  if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
-  throw new StrongModeTypeError(object, found, expected);
-}
-
 throwUnimplementedError(String message) {
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new UnimplementedError(message);
 }
 
 assertFailed(message) {
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new AssertionErrorImpl(message);
 }
 
@@ skipping 10 matching lines @@
   throw new NoSuchMethodError(
       null, new Symbol('<Unexpected Null Value>'), null, null, null);
 }
 
 throwNoSuchMethodError(Object receiver, Symbol memberName,
     List positionalArguments, Map<Symbol, dynamic> namedArguments) {
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new NoSuchMethodError(
       receiver, memberName, positionalArguments, namedArguments);
 }