diff --git a/remix-debug/src/solidity-decoder/localDecoder.js b/remix-debug/src/solidity-decoder/localDecoder.js
index b4dab50cec..5cc2c35c6f 100644
--- a/remix-debug/src/solidity-decoder/localDecoder.js
+++ b/remix-debug/src/solidity-decoder/localDecoder.js
@@ -9,7 +9,7 @@ async function solidityLocals (vmtraceIndex, internalTreeCall, stack, memory, st
   const locals = {}
   memory = formatMemory(memory)
   let anonymousIncr = 1
-  for (var local in scope.locals) {
+  for (let local in scope.locals) {
     var variable = scope.locals[local]
     if (variable.stackDepth < stack.length && variable.sourceLocation.start <= currentSourceLocation.start) {
       let name = variable.name
diff --git a/remix-debug/src/solidity-decoder/types/Struct.js b/remix-debug/src/solidity-decoder/types/Struct.js
index 57e9d01789..7d3c8fa967 100644
--- a/remix-debug/src/solidity-decoder/types/Struct.js
+++ b/remix-debug/src/solidity-decoder/types/Struct.js
@@ -10,8 +10,7 @@ class Struct extends RefType {
 
   async decodeFromStorage (location, storageResolver) {
     const ret = {}
-    for (var k in this.members) {
-      const item = this.members[k]
+    for (var item of this.members) {
       const globalLocation = {
         offset: location.offset + item.storagelocation.offset,
         slot: util.add(location.slot, item.storagelocation.slot)
diff --git a/remix-debug/src/storage/mappingPreimages.js b/remix-debug/src/storage/mappingPreimages.js
index 9280e1fd62..e839ee981b 100644
--- a/remix-debug/src/storage/mappingPreimages.js
+++ b/remix-debug/src/storage/mappingPreimages.js
@@ -17,7 +17,7 @@ async function decodeMappingsKeys (web3, storage, corrections, callback) {
   const ret = {}
   if (!corrections.length) corrections.push({offset: 0, slot: 0})
   for (let hashedLoc in storage) {
-    let preimage
+    var preimage
     try {
       const key = storage[hashedLoc].key
       for (let k in corrections) {