Support runtime check of function types.

sdk/lib/_internal/compiler/implementation/resolution/members.dart

Index: sdk/lib/_internal/compiler/implementation/resolution/members.dart
diff --git a/sdk/lib/_internal/compiler/implementation/resolution/members.dart b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
index e6fd47862ac1280627bedfdbbf339ae86f10a11c..92cce46bcd3525a4d57b2d8928cc74f2109d402a 100644
--- a/sdk/lib/_internal/compiler/implementation/resolution/members.dart
+++ b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
@@ -1866,6 +1866,12 @@ class ResolverVisitor extends CommonResolverVisitor<Element> {
       }
       parameterNodes = parameterNodes.tail;
     });
+    if (inCheckContext) {
+      functionParameters.forEachParameter((Element element) {
+        compiler.enqueuer.resolution.registerIsCheck(
+            element.computeType(compiler), mapping);
+      });
+    }
   }
 
   visitCascade(Cascade node) {
@@ -1963,6 +1969,9 @@ class ResolverVisitor extends CommonResolverVisitor<Element> {
     scope = oldScope;
     enclosingElement = previousEnclosingElement;
 
+    if (function.computeType(compiler).containsTypeVariables) {
+      world.registerGenericClosure(function, mapping);
+    }
     world.registerInstantiatedClass(compiler.functionClass, mapping);
   }