Record names of constructors and use that to implement Object.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 visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 1187 matching lines @@
   bool hasExpectedType() => builtin || type.isUnknown() || left.isString();
 
   HType computeDesiredInputType(HInstruction input) {
     // TODO(floitsch): we want the target to be a function.
     if (input == target) return HType.UNKNOWN;
     if (isString() || left.isString()) {
       return (input == left) ? HType.STRING : HType.UNKNOWN;
     }
     if (right.isString()) return HType.STRING;
     if (isNumber() || left.isNumber() || right.isNumber()) return HType.NUMBER;
-    if (type.isUnknown()) return HType.NUMBER;
     return HType.UNKNOWN;
   }
 }
 
 class HDivide extends HBinaryArithmetic {
   HDivide(HStatic target, HInstruction left, HInstruction right)
       : super(target, left, right);
   accept(HVisitor visitor) => visitor.visitDivide(this);
   num evaluate(num a, num b) => a / b;
   bool typeEquals(other) => other is HDivide;
@@ skipping 775 matching lines @@
                    HInstruction first,
                    HInstruction second)
       : super(<HInstruction>[first, second]);
   toString() => operation;
   accept(HVisitor visitor) => visitor.visitLogicalOperator(this);
   HInstruction get left() => inputs[0];
   HInstruction get right() => inputs[1];
   HType computeType() => HType.BOOLEAN;
   bool hasExpectedType() => true;
 }