Return null from stringValue and call slowToString() instead of toString().

dart/frog/leg/ssa/nodes.dart

 // Copyright (c) 2011, 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.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBailoutTarget(HBailoutTarget node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
@@ skipping 1181 matching lines @@
   bool builtin = false;
   /** The first input must be the target. */
   HInvokeStatic(selector, inputs) : super(selector, inputs);
   toString() => 'invoke static: ${element.name}';
   accept(HVisitor visitor) => visitor.visitInvokeStatic(this);
   Element get element() => target.element;
   HStatic get target() => inputs[0];
 
   HType computeType() {
     if (element.isFactoryConstructor()
-        && element.enclosingElement.name.toString() == 'List') {
+        && element.enclosingElement.name.slowToString() == 'List') {
       builtin = true;
       return HType.ARRAY;
     }
     return HType.UNKNOWN;
   }
 
   bool hasExpectedType() => builtin;
 }
 
 class HInvokeSuper extends HInvokeStatic {
@@ skipping 101 matching lines @@
     // Inputs for foreigns must not be generated at use site. In particular
     // literals would make troubles as we do a search/replace which would be
     // complicated if we had to stringify literals first.
     for (HInstruction input in inputs) {
       input.clearGenerateAtUseSite();
     }
   }
   accept(HVisitor visitor) => visitor.visitForeign(this);
 
   HType computeType() {
-    if (declaredType.stringValue == 'bool') return HType.BOOLEAN;
-    if (declaredType.stringValue == 'int') return HType.INTEGER;
-    if (declaredType.stringValue == 'num') return HType.NUMBER;
-    if (declaredType.stringValue == 'String') return HType.STRING;
+    if (declaredType.slowToString() == 'bool') return HType.BOOLEAN;
+    if (declaredType.slowToString() == 'int') return HType.INTEGER;
+    if (declaredType.slowToString() == 'num') return HType.NUMBER;
+    if (declaredType.slowToString() == 'String') return HType.STRING;
     return HType.UNKNOWN;
   }
 
   bool hasExpectedType() => true;
 }
 
 class HForeignNew extends HForeign {
   ClassElement element;
   HForeignNew(this.element, List<HInstruction> inputs)
       : super(const SourceString("new"), const SourceString("Object"), inputs);
@@ skipping 914 matching lines @@
 
   HInstruction get expression() => inputs[0];
 
   HType computeType() => HType.BOOLEAN;
   bool hasExpectedType() => true;
 
   accept(HVisitor visitor) => visitor.visitIs(this);
 
   toString() => "$expression is $typeExpression";
 }