Adjusts dart2js SSA builder to tolerate method type arguments.

pkg/compiler/lib/src/ssa/builder.dart

Index: pkg/compiler/lib/src/ssa/builder.dart
diff --git a/pkg/compiler/lib/src/ssa/builder.dart b/pkg/compiler/lib/src/ssa/builder.dart
index 50db1bf00553b3735936d472965f8e9013c595b7..222d7e37d9088db81950a9b7a7420a4bb4d8c7e5 100644
--- a/pkg/compiler/lib/src/ssa/builder.dart
+++ b/pkg/compiler/lib/src/ssa/builder.dart
@@ -4766,6 +4766,17 @@ class SsaBuilder extends ast.Visitor
       // The type variable is stored on the object.
       return readTypeVariable(member.enclosingClass, type.element,
           sourceInformation: sourceInformation);
+    } else if (type is MethodTypeVariableType) {

[Johnni Winther, 2016/05/11 12:58:30]

I think this should be the first test, so that we do not try to access the rti
value from elsewhere.

Maybe add a test for something like:

class Class<S> {
  factory Class(S s) { 
    foo<T>(var) => t is T; // Don't look for T in Class
    foo<S>(s);
  }
}

+      // TODO(eernst): The enclosing `else if` was added to provide minimal
+      // support for generic methods: The method type arguments are always
+      // pretending to have the value `dynamic`. Revise for full support.
+      DynamicType type = const DynamicType();
+      JavaScriptBackend backend = compiler.backend;
+      ClassElement cls = backend.helpers.DynamicRuntimeType;
+      HInstruction instruction =
+          new HDynamicType(type, new TypeMask.exact(cls, compiler.world));
+      add(instruction);
+      return instruction;
     } else {
       reporter.internalError(
           type.element, 'Unexpected type variable in static context.');