Fix type propagation for and operator.

pkg/compiler/lib/src/ssa/invoke_dynamic_specializers.dart

 // Copyright (c) 2013, 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;
 
 /**
  * [InvokeDynamicSpecializer] and its subclasses are helpers to
  * optimize intercepted dynamic calls. It knows what input types
  * would be beneficial for performance, and how to change a invoke
@@ skipping 546 matching lines @@
 
   BinaryOperation operation(ConstantSystem constantSystem) {
     return constantSystem.bitAnd;
   }
 
   TypeMask computeTypeFromInputTypes(HInvokeDynamic instruction,
                                      Compiler compiler) {
     HInstruction left = instruction.inputs[1];
     HInstruction right = instruction.inputs[2];
     JavaScriptBackend backend = compiler.backend;
-    if (left.isUInt31(compiler) || right.isUInt31(compiler)) {
+    if (left.isPrimitiveOrNull(compiler) &&
+        (left.isUInt31(compiler) || right.isUInt31(compiler))) {
       return backend.uint31Type;
     }
     return super.computeTypeFromInputTypes(instruction, compiler);
   }
 
   HInstruction newBuiltinVariant(HInvokeDynamic instruction,
                                  Compiler compiler) {
     JavaScriptBackend backend = compiler.backend;
     return new HBitAnd(
         instruction.inputs[1], instruction.inputs[2],
@@ skipping 162 matching lines @@
     return constantSystem.codeUnitAt;
   }
 
   HInstruction tryConvertToBuiltin(HInvokeDynamic instruction,
                                    Compiler compiler) {
     // TODO(sra): Implement a builtin HCodeUnitAt instruction and the same index
     // bounds checking optimizations as for HIndex.
     return null;
   }
 }