Account for ref and ptr objects

Author: yglukhov

compiler/sigmatch.nim

@@ -1704,8 +1704,12 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
 
             # Fallback for computed generic type aliases (bug #25340):
             # Check if the aliased types (last elements) have inheritance relationship
-            let aLast = roota.last
-            let fLast = rootf.last
+            var aLast = roota.last
+            var fLast = rootf.last
+            # Handle ref/ptr types - unwrap to get the underlying object
+            if aLast.kind == fLast.kind and aLast.kind in {tyRef, tyPtr}:
+              aLast = aLast.elementType
+              fLast = fLast.elementType
             if aLast.kind == tyObject and fLast.kind == tyObject and trIsOutParam notin flags:
               let depth = isObjectSubtype(c, aLast, fLast, nil)
               if depth > 0:

tests/typerel/t25340.nim

@@ -70,3 +70,38 @@ block:
   assert JSExternObj[HTMLElement] is JSExternObj[JSObj]
   assert JSExternObj[Document] is JSExternObj[JSObj]
 
+block: # Refs
+  type
+    JSObj {.inheritable.} = object
+    JSExternObjBase {.inheritable, pure.} = ref object
+    HTMLElement = object of JSObj
+    Document = object of HTMLElement
+
+  macro parent(t: typedesc): untyped =
+    let n = t.getType()[1]
+    if $n == "JSObj":
+      return ident"JSExternObjBase"
+    else:
+      let imp = n.getTypeImpl()
+      imp.expectKind(nnkObjectTy)
+      let base = imp[1][0]
+      result = newTree(nnkRefTy,
+                       newTree(nnkObjectTy,
+                               newEmptyNode(),
+                               newTree(nnkOfInherit,
+                                       newTree(nnkBracketExpr, ident"JSExternObj", base)),
+                               newEmptyNode()))
+
+  type
+    JSExternObj[T] = parent(T)
+
+  var a: JSExternObj[JSObj]
+  var d: JSExternObj[Document]
+  a = d
+  proc p(a: JSExternObj[JSObj]) =
+    discard
+  p(d)
+
+  assert JSExternObj[Document] is JSExternObj[HTMLElement]
+  assert JSExternObj[HTMLElement] is JSExternObj[JSObj]
+  assert JSExternObj[Document] is JSExternObj[JSObj]