fix: parameter type inferring bug

fix: mtshiba/pylyzer#47

Author: mtshiba

crates/erg_compiler/context/inquire.rs

@@ -552,7 +552,7 @@ impl Context {
     ) -> Triple<VarInfo, TyCheckError> {
         // get_attr_info(?T, aaa) == None
         // => ?T(<: Structural({ .aaa = ?U }))
-        if self.in_subr() && PYTHON_MODE {
+        if PYTHON_MODE && obj.var_info().is_some_and(|vi| vi.is_untyped_parameter()) {
             let t = free_var(self.level, Constraint::new_type_of(Type));
             if let Some(fv) = obj.ref_t().as_free() {
                 if fv.get_sub().is_some() {
@@ -894,7 +894,7 @@ impl Context {
     ) -> SingleTyCheckResult<VarInfo> {
         // search_method_info(?T, aaa, pos_args: [1, 2]) == None
         // => ?T(<: Structural({ .aaa = (self: ?T, ?U, ?V) -> ?W }))
-        if PYTHON_MODE && self.in_subr() {
+        if PYTHON_MODE && obj.var_info().is_some_and(|vi| vi.is_untyped_parameter()) {
             let nd_params = pos_args
                 .iter()
                 .map(|_| ParamTy::Pos(free_var(self.level, Constraint::new_type_of(Type))))
@@ -2559,10 +2559,6 @@ impl Context {
         }
     }
 
-    pub(crate) fn in_subr(&self) -> bool {
-        self.kind.is_subr() || self.get_outer().map_or(false, |ctx| ctx.in_subr())
-    }
-
     pub(crate) fn gen_type(&self, ident: &ast::Identifier) -> Type {
         let vis = ident.vis.display_as_accessor();
         mono(format!("{}{vis}{}", self.name, ident.inspect()))

crates/erg_compiler/hir.rs

@@ -2529,6 +2529,14 @@ impl Expr {
         }
     }
 
+    pub fn var_info(&self) -> Option<&VarInfo> {
+        match self {
+            Expr::Accessor(acc) => Some(acc.var_info()),
+            Expr::TypeAsc(t_asc) => t_asc.expr.var_info(),
+            _ => None,
+        }
+    }
+
     /// 参照するオブジェクト自体が持っている名前(e.g. Int.qual_name == Some("int"), Socket!.qual_name == Some("io.Socket!"))
     pub fn qual_name(&self) -> Option<Str> {
         match self {

crates/erg_compiler/varinfo.rs

@@ -329,4 +329,8 @@ impl VarInfo {
             AbsLocation::unknown(),
         )
     }
+
+    pub fn is_untyped_parameter(&self) -> bool {
+        self.kind.is_parameter() && self.t.is_unbound_var()
+    }
 }