fixes #13110

compiler/liftdestructors.nim

@@ -846,7 +846,6 @@ proc isEmptyContainer(g: ModuleGraph, t: PType): bool =
   (t.kind == tyArray and lengthOrd(g.config, t[0]) == 0) or
     (t.kind == tySequence and t[0].kind == tyError)
 
-
 proc createTypeBoundOps(g: ModuleGraph; c: PContext; orig: PType; info: TLineInfo) =
   ## In the semantic pass this is called in strategic places
   ## to ensure we lift assignment, destructors and moves properly.

compiler/sempass2.nim

@@ -906,16 +906,26 @@ proc track(tracked: PEffects, n: PNode) =
   of nkTypeSection, nkProcDef, nkConverterDef, nkMethodDef, nkIteratorDef,
       nkMacroDef, nkTemplateDef, nkLambda, nkDo, nkFuncDef:
     discard
-  of nkCast, nkHiddenStdConv, nkHiddenSubConv, nkConv:
+  of nkCast:
     if n.len == 2:
       track(tracked, n[1])
       if tracked.owner.kind != skMacro:
         createTypeBoundOps(tracked, n.typ, n.info)
+  of nkHiddenStdConv, nkHiddenSubConv, nkConv:
+    if n.len == 2:
+      track(tracked, n[1])
+      if tracked.owner.kind != skMacro:
+        createTypeBoundOps(tracked, n.typ, n.info)
+        # This is a hacky solution in order to fix bug #13110. Hopefully
+        # a better solution will come up eventually.
+        if n[1].typ.kind != tyString:
+          createTypeBoundOps(tracked, n[1].typ, n[1].info)
   of nkObjUpConv, nkObjDownConv, nkChckRange, nkChckRangeF, nkChckRange64:
     if n.len == 1:
       track(tracked, n[0])
       if tracked.owner.kind != skMacro:
         createTypeBoundOps(tracked, n.typ, n.info)
+        createTypeBoundOps(tracked, n[0].typ, n[0].info)
   of nkBracket:
     for i in 0..<n.safeLen: track(tracked, n[i])
     if tracked.owner.kind != skMacro:

tests/generics/trtree.nim

@@ -4,8 +4,11 @@ discard """
   target: "c"
   joinable: false
 disabled: 32bit
+  cmd: "nim c --gc:arc $file"
 """
 
+# bug #13110: This test failed with --gc:arc.
+
 # this test wasn't written for 32 bit
 # don't join because the code is too messy.
 
@@ -527,7 +530,7 @@ proc findLeaf[M, D: Dim; RT, LT](t: RTree[M, D, RT, LT]; leaf: L[D, RT, LT]): Le
 proc condenseTree[M, D: Dim; RT, LT](t: RTree[M, D, RT, LT]; leaf: Leaf[M, D, RT, LT]) =
   var n: H[M, D, RT, LT] = leaf
   var q = newSeq[H[M, D, RT, LT]]()
-  var b: type(leaf.a[0].b)
+  var b: typeof(leaf.a[0].b)
   while n != t.root:
     let p = Node[M, D, RT, LT](n.parent)
     var i = 0