Merge pull request #3800 from Kalibryyy/master

Author: markerikson

packages/toolkit/src/mapBuilders.ts

@@ -166,7 +166,7 @@ export function executeReducerBuilderCallback<S>(
       }
       if (type in actionsMap) {
         throw new Error(
-          '`builder.addCase` cannot be called with two reducers for the same action type'
+          `\`builder.addCase\` cannot be called with two reducers for the same action type '${type}'`
         )
       }
       actionsMap[type] = reducer

packages/toolkit/src/tests/createReducer.test.ts

@@ -460,7 +460,7 @@ describe('createReducer', () => {
             .addCase(decrement, (state, action) => state - action.payload)
         )
       ).toThrowErrorMatchingInlineSnapshot(
-        '"`builder.addCase` cannot be called with two reducers for the same action type"'
+        '"`builder.addCase` cannot be called with two reducers for the same action type \'increment\'"'
       )
       expect(() =>
         createReducer(0, (builder) =>
@@ -470,7 +470,7 @@ describe('createReducer', () => {
             .addCase(decrement, (state, action) => state - action.payload)
         )
       ).toThrowErrorMatchingInlineSnapshot(
-        '"`builder.addCase` cannot be called with two reducers for the same action type"'
+        '"`builder.addCase` cannot be called with two reducers for the same action type \'increment\'"'
       )
     })