Add regression test for r24720.

sdk/lib/_internal/compiler/implementation/ssa/builder.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/builder.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
index 332648302db14261ebbf283dddf530620be415d7..c495962b86ca07f16a3afdd979ddd8e9bf8873ab 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
@@ -1347,6 +1347,10 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
         // type parameters. Those values are in the [supertype]
         // declaration of [subclass].
         ClassElement subclass = inlinedFromElement.getEnclosingClass();
+        // If [inlinedFromElement] is generative constructor [superclass] is a

[karlklose, 2013/07/05 06:31:34]

'is a' and a comma or 'then' after constructor (also in the next sentence).

[Johnni Winther, 2013/07/05 07:11:24]

Done.

+        // a superclass of [subclass]. If [inlinedFromElement] is a redirecting
+        // constructor [superclass] is the same as [subclass]. Using 
+        // [DartType.asInstanceOf] handles both these cases.
         InterfaceType supertype = subclass.thisType.asInstanceOf(superclass);
         Link<DartType> typeVariables = superclass.typeVariables;
         supertype.typeArguments.forEach((DartType argument) {