fixes #25174; tyOr handling in tyBuiltInTypeClass branch of typeRel

compiler/sigmatch.nim

@@ -1742,7 +1742,17 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
       if ff != nil:
         result = typeRel(c, ff, a, flags)
   of tyGenericInvocation:
-    var x = a.skipGenericAlias
+    var x = a
+    while x != nil:
+      if x.kind == tyAlias:
+        x = x.last
+      elif x.isGenericAlias:
+        if f[0] == x[0]:
+          break
+        else:
+          x = x.last
+      else:
+        break
     if x.kind == tyGenericParam and x.len > 0:
       x = x.last
     let concpt = f.reduceToBase
@@ -1751,7 +1761,7 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
       preventHack = true
       x = x.last
     # XXX: This is very hacky. It should be moved back into liftTypeParam
-    if x.kind in {tyGenericInst, tyArray} and
+    if x.kind in {tyArray} and
       c.calleeSym != nil and
       c.calleeSym.kind in {skProc, skFunc} and c.call != nil and not preventHack:
       let inst = prepareMetatypeForSigmatch(c.c, c.bindings, c.call.info, f)
@@ -1807,10 +1817,12 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
           else:
             let key = f[i]
             let old = lookup(c.bindings, key)
-            if old == nil:
+            if typeRel(c, key, x, flags) == isNone:
+              result = isNone
+            elif old == nil or typeRel(c, old, x, flags + {trDontBind}) > isNone:
               put(c, key, x)
-            elif typeRel(c, old, x, flags + {trDontBind}) == isNone:
-              return isNone
+            else:
+              result = isNone
       var depth = -1
       if fobj != nil and aobj != nil and askip == fskip:
         depth = isObjectSubtype(c, aobj, fobj, f)
@@ -1891,6 +1903,11 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
             return isNone
         if doBind: put(c, f, a)
         return isGeneric
+      elif effectiveArgType.kind == tyOr:
+        for kid in effectiveArgType.kids:
+          if typeRel(c, f, kid, flags) >= isSubtype:
+            result = isGeneric
+            break
       else:
         return isNone
   of tyUserTypeClassInst, tyUserTypeClass:

tests/typerel/tsigmatch.nim

@@ -4,3 +4,16 @@ block: # bug #13618
 
   doAssert test(^1) == 1
   doAssert test(1) == 1
+
+block: # #25174
+  type Foo = object
+  type Bar = object
+  type Quz = object
+
+  proc bar[T: Foo | Bar](x: T): string =
+    return $typeof(T)
+  proc bar[T: object](x: T): string =
+    return $typeof(T)
+  doAssert bar(Foo()) == "Foo"
+  doAssert bar(Bar()) == "Bar"
+  doAssert bar(Quz()) == "Quz"