fix(model): Static type="checkbox" was being ignored when used with v-bind

fix vuejs#7811

Author: Hiroki Osame

src/platforms/web/compiler/modules/model.js

@@ -34,7 +34,7 @@ function preTransformNode (el: ASTElement, options: CompilerOptions) {
     if (map[':type'] || map['v-bind:type']) {
       typeBinding = getBindingAttr(el, 'type')
     }
-    if (!typeBinding && map['v-bind']) {
+    if (!map.type && !typeBinding && map['v-bind']) {
       typeBinding = `(${map['v-bind']}).type`
     }
 

test/unit/features/directives/model-checkbox.spec.js

@@ -337,4 +337,14 @@ describe('Directive v-model checkbox', () => {
       expect(vm.$el.children[1].textContent).toBe('false')
     }).then(done)
   })
+
+  it('should have type="checkbox"', () => {
+    const vm = new Vue({
+      data: {
+        test: true
+      },
+      template: '<input type="checkbox" v-model="test" v-bind="$attrs">'
+    }).$mount()
+    expect(vm.$el.type).toBe('checkbox')
+  })
 })