fix: subtype check bug

crates/erg_compiler/context/compare.rs

@@ -899,19 +899,20 @@ impl Context {
                 self.supertype_of_tp(sup_p, fv.unsafe_crack(), variance)
             }
             (TyParam::Erased(t), _) => match variance {
-                Variance::Contravariant => self.subtype_of(t, &self.get_tp_t(sub_p).unwrap_or(Obj)),
+                Variance::Contravariant => {
-                Variance::Covariant => self.supertype_of(t, &self.get_tp_t(sub_p).unwrap_or(Obj)),
-                Variance::Invariant => {
                     let rhs = self.get_tp_t(sub_p).unwrap_or(Obj);
-                    self.same_type_of(t, &rhs) || self.same_type_of(t, &rhs.derefine())
+                    self.subtype_of(t, &rhs)
+                }
+                // REVIEW: invariant type parameters check
+                Variance::Covariant | Variance::Invariant => {
+                    let rhs = self.get_tp_t(sub_p).unwrap_or(Obj);
+                    self.supertype_of(t, &rhs)
                 }
             },
             (_, TyParam::Erased(t)) => match variance {
                 Variance::Contravariant => self.subtype_of(&self.get_tp_t(sup_p).unwrap_or(Obj), t),
-                Variance::Covariant => self.supertype_of(&self.get_tp_t(sup_p).unwrap_or(Obj), t),
+                Variance::Covariant | Variance::Invariant => {
-                Variance::Invariant => {
+                    self.supertype_of(&self.get_tp_t(sup_p).unwrap_or(Obj), t)
-                    let lhs = self.get_tp_t(sup_p).unwrap_or(Obj);
-                    self.same_type_of(&lhs, t) || self.same_type_of(&lhs.derefine(), t)
                 }
             },
             (TyParam::Array(sup), TyParam::Array(sub))

crates/erg_compiler/context/inquire.rs

@@ -1967,7 +1967,11 @@ impl Context {
                     .map_or(vec![], |ctx| vec![ctx])
             })
             .unwrap_or_default();
-        let three = self.get_nominal_type_ctx(instance).map(|ty| &ty.ctx);
+        let three = self
+            .get_nominal_super_type_ctxs(instance)
+            .unwrap_or_default()
+            .into_iter()
+            .map(|ctx| &ctx.ctx);
         let fallbacks = one.into_iter().chain(two).chain(three);
         for typ_ctx in fallbacks {
             // staticmethod __call__

crates/erg_compiler/lib/external/torch.d/__init__.d.er

@@ -45,5 +45,11 @@
     ) => NoneType
     # TODO: S bound
     item: |T|(self: Ref .Tensor!(T, _)) -> T
+    to: (|T, S: [Nat; _]|(
+        self: .Tensor!(T, S),
+        other: .DType or .Device,
+        non_blocking := Bool,
+        copy := Bool,
+    ) -> .Tensor!(T, S))
 
 .relu: |T, S: [Nat; _]|(x: .Tensor!(T, S)) -> .Tensor!(T, S)