Fix bug in combination of bounded and exact types.

lib/compiler/implementation/ssa/types.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.
 
 abstract class HType {
   const HType();
 
   /**
    * Returns an [HType] that represents [type] and all types that have
    * [type] as supertype.
@@ skipping 630 matching lines @@
 
   Element lookupMember(SourceString name) {
     ClassElement classElement = type.element;
     return classElement.lookupMember(name);
   }
 
   HType combine(HType other) {
     if (other.isExact()) {
       HExactType concrete = other;
       if (this.type === concrete.type) return this;
+    } else if (other is HBoundedType) {
+      HBoundedType bounded = other;
+      if (this.type === bounded.type) return other;

[ngeoffray, 2012/05/23 14:09:45]

This is OK for the union but not for the intersection. Maybe you should get rid
of combine and implement union/intersection for HBoundedType and HExactType.

[karlklose, 2012/05/24 12:37:49]

Done.

     }
     if (other.isUnknown()) return this;
     return HType.CONFLICTING;
   }
 
   HType union(HType other) {
     if (other.isNull()) return HType.CONFLICTING;
     return combine(other);
   }
 }
@@ skipping 59 matching lines @@
   HType intersection(HType other) {
     if (other.isString()) return HType.STRING;
     if (other.isStringOrNull()) {
       return canBeNull() ? HType.STRING_OR_NULL : HType.STRING;
     }
     if (other.isReadableArray()) return HType.CONFLICTING;
     if (other.isIndexablePrimitive()) return HType.STRING;
     return super.intersection(other);
   }
 }