fix(runtime-core): fix resolving inheritAttrs from mixins

packages/runtime-core/__tests__/rendererAttrsFallthrough.spec.ts

@@ -301,6 +301,34 @@ describe('attribute fallthrough', () => {
     expect(root.innerHTML).toMatch(`<div>1</div>`)
   })
 
+  // #3741
+  it('should not fallthrough with inheritAttrs: false from mixins', () => {
+    const Parent = {
+      render() {
+        return h(Child, { foo: 1, class: 'parent' })
+      }
+    }
+
+    const mixin = {
+      inheritAttrs: false
+    }
+
+    const Child = defineComponent({
+      mixins: [mixin],
+      props: ['foo'],
+      render() {
+        return h('div', this.foo)
+      }
+    })
+
+    const root = document.createElement('div')
+    document.body.appendChild(root)
+    render(h(Parent), root)
+
+    // should not contain class
+    expect(root.innerHTML).toMatch(`<div>1</div>`)
+  })
+
   it('explicit spreading with inheritAttrs: false', () => {
     const Parent = {
       render() {

packages/runtime-core/src/componentOptions.ts

@@ -556,7 +556,8 @@ export function applyOptions(
     renderTriggered,
     errorCaptured,
     // public API
-    expose
+    expose,
+    inheritAttrs
   } = options
 
   const publicThis = instance.proxy!
@@ -753,6 +754,8 @@ export function applyOptions(
     if (__COMPAT__ && isCompatEnabled(DeprecationTypes.FILTERS, instance)) {
       resolveInstanceAssets(instance, options, FILTERS)
     }
+
+    if (inheritAttrs !== undefined) instance.type.inheritAttrs = inheritAttrs
   }
 
   // lifecycle options