use separate type flag

compiler/ast.nim

@@ -447,6 +447,8 @@ const
   tfReturnsNew* = tfInheritable
   tfNonConstExpr* = tfExplicitCallConv
     ## tyFromExpr where the expression shouldn't be evaluated as a static value
+  tfGenericHasDestructor* = tfExplicitCallConv
+    ## tyGenericBody where an instance has a generated destructor
   skError* = skUnknown
 
 var

compiler/liftdestructors.nim

@@ -1279,7 +1279,7 @@ proc createTypeBoundOps(g: ModuleGraph; c: PContext; orig: PType; info: TLineInf
   # for user defined generic destructors:
   let origRoot = genericRoot(orig)
   if origRoot != nil:
-    incl origRoot.flags, tfCheckedForDestructor
+    incl origRoot.flags, tfGenericHasDestructor
 
   let skipped = orig.skipTypes({tyGenericInst, tyAlias, tySink})
   if isEmptyContainer(skipped) or skipped.kind == tyStatic: return

compiler/semstmts.nim

@@ -2052,7 +2052,7 @@ proc checkedForDestructor(t: PType): bool =
     return true
   # maybe another instance was instantiated, marking the generic root:
   let root = genericRoot(t)
-  if root != nil and tfCheckedForDestructor in root.flags:
+  if root != nil and tfGenericHasDestructor in root.flags:
     return true
   result = false