Remove wrong assertion, and make sure we only change the type of constant lists.

sdk/lib/_internal/compiler/implementation/ssa/nodes.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;
 
 abstract class HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
@@ skipping 1915 matching lines @@
   bool isConstantFalse() => constant.isFalse();
   bool isConstantTrue() => constant.isTrue();
   bool isConstantSentinel() => constant.isSentinel();
 
   bool isInterceptor(Compiler compiler) => constant.isInterceptor();
 
   // Maybe avoid this if the literal is big?
   bool isCodeMotionInvariant() => true;
 
   set instructionType(type) {
-    assert((type.isEmpty && super.instructionType.isEmpty)
-           || !type.isNullable);
-    assert(!isConstantNull() || (type.isEmpty && type.isNullable));
+    // Only lists can be specialized. The SSA builder uses the
+    // inferrer for finding the type of a constant list. We should
+    // have the constant know its type instead.
+    if (!isConstantList()) return;
     super.instructionType = type;
   }
 }
 
 class HNot extends HInstruction {
   HNot(HInstruction value, TypeMask type) : super(<HInstruction>[value], type) {
     setUseGvn();
   }
 
   accept(HVisitor visitor) => visitor.visitNot(this);
@@ skipping 957 matching lines @@
 class HDynamicType extends HRuntimeType {
   HDynamicType(DynamicType dartType, TypeMask instructionType)
       : super(const <HInstruction>[], dartType, instructionType);
 
   accept(HVisitor visitor) => visitor.visitDynamicType(this);
 
   int typeCode() => HInstruction.DYNAMIC_TYPE_TYPECODE;
 
   bool typeEquals(HInstruction other) => other is HDynamicType;
 }