bugfix: type alias to generic; generic type not stripped away from for loop variable

tests/compile/tgenericprop.nim

@@ -0,0 +1,12 @@
+
+type
+  TProperty[T] = object of TObject
+    getProc: proc(property: TProperty[T]): T
+    setProc: proc(property: TProperty[T], value: T)
+    value: T
+
+proc newProperty[T](value: TObject): TProperty[T] =
+  result.getProc = proc (property: TProperty[T]) =
+    return property.value
+
+