fixes #6682

compiler/ast.nim

@@ -1448,6 +1448,10 @@ proc rawAddSon*(father, son: PType) =
   add(father.sons, son)
   if not son.isNil: propagateToOwner(father, son)
 
+proc rawAddSonNoPropagationOfTypeFlags*(father, son: PType) =
+  if isNil(father.sons): father.sons = @[]
+  add(father.sons, son)
+
 proc addSonNilAllowed*(father, son: PNode) =
   if isNil(father.sons): father.sons = @[]
   add(father.sons, son)

compiler/semtypes.nim

@@ -296,7 +296,9 @@ proc semArray(c: PContext, n: PNode, prev: PType): PType =
     base = semTypeNode(c, n.sons[2], nil)
     # ensure we only construct a tyArray when there was no error (bug #3048):
     result = newOrPrevType(tyArray, prev, c)
-    addSonSkipIntLit(result, indx)
+    # bug #6682: Do not propagate initialization requirements etc for the
+    # index type:
+    rawAddSonNoPropagationOfTypeFlags(result, indx)
     addSonSkipIntLit(result, base)
   else:
     localError(n.info, errArrayExpectsTwoTypeParams)

compiler/semtypinst.nim

@@ -522,7 +522,8 @@ proc replaceTypeVarsTAux(cl: var TReplTypeVars, t: PType): PType =
             if r2.kind in {tyPtr, tyRef}:
               r = skipTypes(r2, {tyPtr, tyRef})
           result.sons[i] = r
-          propagateToOwner(result, r)
+          #if result.kind != tyArray or i != 0:
+          #  propagateToOwner(result, r)
       # bug #4677: Do not instantiate effect lists
       result.n = replaceTypeVarsN(cl, result.n, ord(result.kind==tyProc))
       case result.kind

tests/notnil/tmust_compile.nim

@@ -0,0 +1,26 @@
+discard """
+  output: '''success'''
+"""
+
+# bug #6682
+
+type
+    Fields = enum
+        A=1, B, C
+
+    Obj = object
+        fld: array[Fields, int]
+
+    AsGeneric[T] = array[Fields, T]
+    Obj2[T] = object
+      fld: AsGeneric[T]
+
+var a: Obj # this works
+
+var arr: array[Fields, int]
+
+var b = Obj() # this doesn't (also doesn't works with additional fields)
+
+var z = Obj2[int]()
+
+echo "success"