diff --git a/libs/remix-debug/src/solidity-decoder/types/RefType.ts b/libs/remix-debug/src/solidity-decoder/types/RefType.ts
index b19f0d3267..8339eee4a2 100644
--- a/libs/remix-debug/src/solidity-decoder/types/RefType.ts
+++ b/libs/remix-debug/src/solidity-decoder/types/RefType.ts
@@ -33,7 +33,7 @@ export class RefType {
     * @param {Object} - storageResolver
     * @return {Object} decoded value
     */
-  async decodeFromStack (stackDepth, stack, memory, storageResolver, cursor) {
+  async decodeFromStack (stackDepth, stack, memory, storageResolver, cursor): Promise<any> {
     if (stack.length - 1 < stackDepth) {
       return { error: '<decoding failed - stack underflow ' + stackDepth + '>', type: this.typeName }
     }