diff --git a/crates/erg_compiler/context/inquire.rs b/crates/erg_compiler/context/inquire.rs
index e50bf2cda..c03923a61 100644
--- a/crates/erg_compiler/context/inquire.rs
+++ b/crates/erg_compiler/context/inquire.rs
@@ -1848,6 +1848,11 @@ impl Context {
                     res
                 }
             }
+            Type::And(_, _) => {
+                let instance =
+                    self.resolve_overload(obj, instance.clone(), pos_args, kw_args, &obj)?;
+                self.substitute_call(obj, attr_name, &instance, pos_args, kw_args, namespace)
+            }
             Type::Failure => Ok(SubstituteResult::Ok),
             _ => {
                 self.substitute_dunder_call(obj, attr_name, instance, pos_args, kw_args, namespace)
@@ -2095,7 +2100,13 @@ impl Context {
                         )?;
                     }
                     let instance = self.instantiate_def_type(&call_vi.t)?;
-                    self.substitute_call(obj, attr_name, &instance, pos_args, kw_args, namespace)?;
+                    let instance = match self
+                        .substitute_call(obj, attr_name, &instance, pos_args, kw_args, namespace)?
+                    {
+                        SubstituteResult::__Call__(instance)
+                        | SubstituteResult::Coerced(instance) => instance,
+                        SubstituteResult::Ok => instance,
+                    };
                     return Ok(SubstituteResult::__Call__(instance));
                 }
             // instance method __call__
@@ -2106,7 +2117,14 @@ impl Context {
                 })
             {
                 let instance = self.instantiate_def_type(&call_vi.t)?;
-                self.substitute_call(obj, attr_name, &instance, pos_args, kw_args, namespace)?;
+                let instance = match self
+                    .substitute_call(obj, attr_name, &instance, pos_args, kw_args, namespace)?
+                {
+                    SubstituteResult::__Call__(instance) | SubstituteResult::Coerced(instance) => {
+                        instance
+                    }
+                    SubstituteResult::Ok => instance,
+                };
                 return Ok(SubstituteResult::__Call__(instance));
             }
         }
diff --git a/tests/should_ok/dunder.er b/tests/should_ok/dunder.er
index c1a94b314..fcf4b247a 100644
--- a/tests/should_ok/dunder.er
+++ b/tests/should_ok/dunder.er
@@ -13,3 +13,7 @@ assert func() == "foo"
 assert module::__file__.endswith "dunder.er"
 assert C.new().__file__ == "bar"
 assert imp.func().endswith "import.er"
+
+discard Str()
+discard Str(1)
+discard Str(bytes("aaa", "utf-8"), "utf-8")