fixes #6073

compiler/sigmatch.nim

@@ -1385,7 +1385,7 @@ proc typeRelImpl(c: var TCandidate, f, aOrig: PType,
     # XXX: This is very hacky. It should be moved back into liftTypeParam
     if x.kind in {tyGenericInst, tyArray} and
        c.calleeSym != nil and
-       c.calleeSym.kind in {skProc, skFunc}:
+       c.calleeSym.kind in {skProc, skFunc} and c.call != nil:
       let inst = prepareMetatypeForSigmatch(c.c, c.bindings, c.call.info, f)
       return typeRel(c, inst, a)
 

tests/types/tyet_another_generic_regression.nim

@@ -0,0 +1,13 @@
+import system
+
+type Bar[T] = ref object
+ value: T
+
+type types = int32|int64 # if I change this to just int32 or int64 it works (compiles)
+
+# if I replace Bar everywhere with seq it also compiles fine
+proc Foo[T: Bar[types]](): T =
+ when T is Bar: nil
+
+discard Foo[Bar[int32]]()
+#bug #6073