diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 16dc159bd..274bb15b9 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -1400,8 +1400,9 @@ proc semAsgn(c: PContext, n: PNode; mode=asgnNormal): PNode =
   # a = b # both are vars, means: a[] = b[]
   # a = b # b no 'var T' means: a = addr(b)
   var le = a.typ
-  if skipTypes(le, {tyGenericInst}).kind != tyVar and
-      isAssignable(c, a) == arNone:
+  if (skipTypes(le, {tyGenericInst}).kind != tyVar and
+        isAssignable(c, a) == arNone) or
+      skipTypes(le, abstractVar).kind in {tyOpenArray, tyVarargs}:
     # Direct assignment to a discriminant is allowed!
     localError(a.info, errXCannotBeAssignedTo,
                renderTree(a, {renderNoComments}))