fixes #6526

tests/overload/tprefer_tygenericinst.nim

@@ -2,7 +2,9 @@ discard """
   output: '''Version 2 was called.
 This has the highest precedence.
 This has the second-highest precedence.
-This has the lowest precedence.'''
+This has the lowest precedence.
+baseobj ==
+true'''
 """
 
 # bug #2220
@@ -26,13 +28,13 @@ template testPred(a: untyped) =
     type SomeA = A|A # A hack to make "A" a typeclass.
 
     when a >= 3:
-      proc p[X](x: X) =
-        echo "This has the highest precedence."
-    when a >= 2:
       proc p[X: A](x: X) =
+        echo "This has the highest precedence."
+    when a == 2:
+      proc p[X: SomeA](x: X) =
         echo "This has the second-highest precedence."
     when a >= 1:
-      proc p[X: SomeA](x: X) =
+      proc p[X](x: X) =
         echo "This has the lowest precedence."
 
     p(B())
@@ -40,3 +42,16 @@ template testPred(a: untyped) =
 testPred(3)
 testPred(2)
 testPred(1)
+
+# bug #6526
+type
+  BaseObj = ref object of RootObj
+  DerivedObj = ref object of BaseObj
+
+proc `==`*[T1, T2: BaseObj](a: T1, b: T2): bool =
+  echo "baseobj =="
+  return true
+
+let a = DerivedObj()
+let b = DerivedObj()
+echo a == b