diff --git a/src/grammar/grammar.ts b/src/grammar/grammar.ts
index b3fdbdc17..4e5eab083 100644
--- a/src/grammar/grammar.ts
+++ b/src/grammar/grammar.ts
@@ -596,7 +596,7 @@ semantics.addOperation<ASTNode>("astOfStatement", {
         return createNode({
             kind: "statement_let_no_type",
             name: arg1.sourceString,
-            expression: arg3.resolve_expression(),
+            expression: arg3.astOfExpression(),
             ref: createRef(this),
         });
     },
diff --git a/src/test/__snapshots__/feature-local-type-inference.spec.ts.snap b/src/test/__snapshots__/feature-local-type-inference.spec.ts.snap
index a61db0b3d..b649a1459 100644
--- a/src/test/__snapshots__/feature-local-type-inference.spec.ts.snap
+++ b/src/test/__snapshots__/feature-local-type-inference.spec.ts.snap
@@ -40,7 +40,7 @@ exports[`feature-local-type-inference should automatically set types for let sta
       "message": "Masterchain support is not enabled for this contract",
     },
     "2": {
-      "message": "Stack undeflow",
+      "message": "Stack underflow",
     },
     "3": {
       "message": "Stack overflow",
diff --git a/src/types/resolveStatements.ts b/src/types/resolveStatements.ts
index 587a213e6..e82813a1b 100644
--- a/src/types/resolveStatements.ts
+++ b/src/types/resolveStatements.ts
@@ -193,7 +193,7 @@ function processStatements(
             const expressionType = getExpType(ctx, s.expression);
 
             // Add variable to statement context
-            if (sctx.vars[s.name]) {
+            if (sctx.vars.has(s.name)) {
                 throwError(`Variable already exists: ${s.name}`, s.ref);
             }
             sctx = addVariable(s.name, expressionType, sctx);