Fix issue 9228, by nopt doing some optimizations in checked mode.

sdk/lib/_internal/compiler/implementation/ssa/bailout.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.
 
 part of ssa;
 
 class BailoutInfo {
   int instructionId;
   int bailoutId;
   BailoutInfo(this.instructionId, this.bailoutId);
@@ skipping 277 matching lines @@
     // will throw [NoSuchMethodError] or [ArgumentError].
     Selector selector = firstUser.selector;
     Selector receiverSelectorOnThrow = null;
     HInstruction receiver = firstUser.getDartReceiver(compiler);
     bool willThrow = false;
     if (receiver == instruction) {
       if (willThrowNoSuchMethodErrorIfNot(selector, speculativeType)) {
         receiverSelectorOnThrow = selector;
         willThrow = true;
       }
-    } else if (willThrowArgumentError(selector, receiver, speculativeType)) {
+    // We need to call the actual method in checked mode to get
+    // the right type error.
+    } else if (!compiler.enableTypeAssertions
+               && willThrowArgumentError(selector, receiver, speculativeType)) {
       willThrow = true;
     }
 
     if (!willThrow) return false;
 
     HTypeConversion check = new HTypeConversion(
             null,
             receiverSelectorOnThrow == null
                 ? HTypeConversion.ARGUMENT_TYPE_CHECK
                 : HTypeConversion.RECEIVER_TYPE_CHECK,
@@ skipping 428 matching lines @@
         hasComplexBailoutTargets = true;
       }
     } else {
       hasComplexBailoutTargets = true;
       blocks.forEach((HBasicBlock block) {
         block.bailoutTargets.add(target);
       });
     }
   }
 }