From ca94de65bf016cc994b7547d5552dc0d8a059ee5 Mon Sep 17 00:00:00 2001
From: Alexey Potapov <pas.aicv@gmail.com>
Date: Thu, 2 Nov 2023 17:58:52 +0300
Subject: [PATCH] fix let return type

---
 lib/src/metta/runner/stdlib.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/src/metta/runner/stdlib.rs b/lib/src/metta/runner/stdlib.rs
index dfb64e0df..652ab02be 100644
--- a/lib/src/metta/runner/stdlib.rs
+++ b/lib/src/metta/runner/stdlib.rs
@@ -869,7 +869,7 @@ use std::collections::HashSet;
 impl Grounded for LetOp {
     fn type_(&self) -> Atom {
         // TODO: Undefined for the argument is necessary to make argument reductable.
-        Atom::expr([ARROW_SYMBOL, ATOM_TYPE_ATOM, ATOM_TYPE_UNDEFINED, ATOM_TYPE_ATOM, ATOM_TYPE_ATOM])
+        Atom::expr([ARROW_SYMBOL, ATOM_TYPE_ATOM, ATOM_TYPE_UNDEFINED, ATOM_TYPE_ATOM, ATOM_TYPE_UNDEFINED])
     }
 
     fn execute(&self, args: &[Atom]) -> Result<Vec<Atom>, ExecError> {
@@ -930,7 +930,7 @@ impl Display for LetVarOp {
 impl Grounded for LetVarOp {
     fn type_(&self) -> Atom {
         // The first argument is an Atom, because it has to be evaluated iteratively
-        Atom::expr([ARROW_SYMBOL, ATOM_TYPE_ATOM, ATOM_TYPE_ATOM, ATOM_TYPE_ATOM])
+        Atom::expr([ARROW_SYMBOL, ATOM_TYPE_ATOM, ATOM_TYPE_ATOM, ATOM_TYPE_UNDEFINED])
     }
 
     fn execute(&self, args: &[Atom]) -> Result<Vec<Atom>, ExecError> {