Allow closures to use method type parameters

This commit fixes a bug where closures did not properly capture
type parameters of methods. A test has been added.

Fixes parapluu#809.

src/back/CodeGen/MethodDecl.hs

@@ -122,7 +122,7 @@ translateGeneral mdecl@(A.Method {A.mbody, A.mlocals})
         (Deref $ Cast (Ptr . AsType $ classTypeName cname) thisVar)
         `Dot`
         name
-      closures = map (\clos -> translateClosure clos typeVars newTable)
+      closures = map (\clos -> translateClosure clos (typeVars ++ mTypeVars) newTable)
                      (reverse (Util.filter A.isClosure mbody))
 
       localize cls prefix fun =

src/tests/encore/parametric/methodPolyClosure.enc

@@ -0,0 +1,18 @@
+read class Bar[t]
+  def bar() : unit
+    println("In Bar")
+  end
+end
+
+read class Foo
+  def foo[ty]() : () -> unit
+    fun() => (new Bar[ty]()).bar()
+  end
+end
+
+active class Main
+  def main() : unit
+    val f = (new Foo()).foo[int]()
+    f()
+  end
+end

src/tests/encore/parametric/methodPolyClosure.out

@@ -0,0 +1 @@
+In Bar