Remove support for String operator + from dart2js.

dart/lib/compiler/implementation/ssa/nodes.dart

Index: dart/lib/compiler/implementation/ssa/nodes.dart
diff --git a/dart/lib/compiler/implementation/ssa/nodes.dart b/dart/lib/compiler/implementation/ssa/nodes.dart
index 0d6bb70f794abbcb31a2ea8f7c1da901b83f25c2..8f108d4c341d7504b214b09d4472e487752e0bd9 100644
--- a/dart/lib/compiler/implementation/ssa/nodes.dart
+++ b/dart/lib/compiler/implementation/ssa/nodes.dart
@@ -1397,11 +1397,7 @@ class HAdd extends HBinaryArithmetic {
       : super(target, left, right);
   accept(HVisitor visitor) => visitor.visitAdd(this);
 
-  bool get builtin() {
-    return (left.isNumber() && right.isNumber())
-            || (left.isString() && right.isString())
-            || (left.isString() && right is HConstant);
-  }
+  bool get builtin() => left.isNumber() && right.isNumber();

[kasperl, 2012/06/18 11:35:55]

This isn't needed anymore.

[ahe, 2012/06/18 11:47:19]

Because this is what the superclass does already. I'll fix this in a follow-up
CL.

 
   HType computeTypeFromInputTypes() {
     if (left.isInteger() && right.isInteger()) return left.propagatedType;
@@ -1409,7 +1405,6 @@ class HAdd extends HBinaryArithmetic {
       if (left.isDouble() || right.isDouble()) return HType.DOUBLE;
       return HType.NUMBER;
     }
-    if (left.isString()) return HType.STRING;
     return HType.UNKNOWN;
   }
 
@@ -1418,11 +1413,6 @@ class HAdd extends HBinaryArithmetic {
     if (propagatedType.isInteger()) {
       return HType.INTEGER;
     }
-    // TODO(floitsch): remove string specialization once string+ is removed
-    // from dart2js.
-    if (propagatedType.isString() || left.isString() || right.isString()) {
-      return HType.STRING;
-    }
     // If the desired output is a number or any of the inputs is a number
     // ask for a number. Note that we might return the input's (say 'left')
     // type depending on its (the 'left's) type. But that shouldn't matter.
@@ -1433,7 +1423,6 @@ class HAdd extends HBinaryArithmetic {
   }
 
   HType get likelyType() {
-    if (left.isString() || right.isString()) return HType.STRING;
     if (left.isTypeUnknown() || left.isNumber()) return HType.NUMBER;
     return HType.UNKNOWN;
   }