fix: type variable bug

erg-lang · Oct 3, 2024 · afa03ab · afa03ab
1 parent d230bb7
commit afa03ab
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/crates/erg_compiler/ty/mod.rs b/crates/erg_compiler/ty/mod.rs
@@ -4172,6 +4172,12 @@ impl Type {
             Self::FreeVar(fv) if fv.is_linked() => fv.unwrap_linked().eliminate_subsup(target),
             Self::FreeVar(ref fv) if fv.constraint_is_sandwiched() => {
                 let (sub, sup) = fv.get_subsup().unwrap();
+                let sub = if sub.addr_eq(target) {
+                    Type::Never
+                } else {
+                    sub
+                };
+                let sup = if sup.addr_eq(target) { Type::Obj } else { sup };
                 let sub = sub.eliminate_subsup(target);
                 let sup = sup.eliminate_subsup(target);
                 self.update_tyvar(sub, sup, None, false);