fix(v-model): should use dynamic directive on input with dynamic v-bind

packages/compiler-dom/__tests__/transforms/__snapshots__/vModel.spec.ts.snap

@@ -1,5 +1,42 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`compiler: transform v-model input w/ dynamic v-bind 1`] = `
+"const _Vue = Vue
+
+return function render() {
+  with (this) {
+    const { vModelDynamic: _vModelDynamic, mergeProps: _mergeProps, createVNode: _createVNode, withDirectives: _withDirectives, createBlock: _createBlock, openBlock: _openBlock } = _Vue
+    
+    return (_openBlock(), _withDirectives(_createBlock(\\"input\\", _mergeProps(obj, {
+      modelValue: model,
+      \\"onUpdate:modelValue\\": $event => (model = $event)
+    }), null, 16 /* FULL_PROPS */, [\\"modelValue\\", \\"onUpdate:modelValue\\"]), [
+      [_vModelDynamic, model]
+    ]))
+  }
+}"
+`;
+
+exports[`compiler: transform v-model input w/ dynamic v-bind 2`] = `
+"const _Vue = Vue
+
+return function render() {
+  with (this) {
+    const { vModelDynamic: _vModelDynamic, createVNode: _createVNode, withDirectives: _withDirectives, resolveDirective: _resolveDirective, createBlock: _createBlock, openBlock: _openBlock } = _Vue
+    
+    const _directive_bind = _resolveDirective(\\"bind\\")
+    
+    return (_openBlock(), _withDirectives(_createBlock(\\"input\\", {
+      modelValue: model,
+      \\"onUpdate:modelValue\\": $event => (model = $event)
+    }, null, 8 /* PROPS */, [\\"modelValue\\", \\"onUpdate:modelValue\\"]), [
+      [_directive_bind, val, key],
+      [_vModelDynamic, model]
+    ]))
+  }
+}"
+`;
+
 exports[`compiler: transform v-model modifiers .lazy 1`] = `
 "const _Vue = Vue
 

packages/compiler-dom/__tests__/transforms/vModel.spec.ts

@@ -63,6 +63,19 @@ describe('compiler: transform v-model', () => {
     expect(generate(root).code).toMatchSnapshot()
   })
 
+  test('input w/ dynamic v-bind', () => {
+    const root = transformWithModel('<input v-bind="obj" v-model="model" />')
+
+    expect(root.helpers).toContain(V_MODEL_DYNAMIC)
+    expect(generate(root).code).toMatchSnapshot()
+
+    const root2 = transformWithModel(
+      '<input v-bind:[key]="val" v-model="model" />'
+    )
+    expect(root2.helpers).toContain(V_MODEL_DYNAMIC)
+    expect(generate(root2).code).toMatchSnapshot()
+  })
+
   test('simple expression for select', () => {
     const root = transformWithModel('<select v-model="model" />')
 

packages/compiler-dom/src/transforms/vModel.ts

@@ -3,7 +3,8 @@ import {
   DirectiveTransform,
   ElementTypes,
   findProp,
-  NodeTypes
+  NodeTypes,
+  hasDynamicKeyVBind
 } from '@vue/compiler-core'
 import { createDOMCompilerError, DOMErrorCodes } from '../errors'
 import {
@@ -75,6 +76,10 @@ export const transformModel: DirectiveTransform = (dir, node, context) => {
               break
           }
         }
+      } else if (hasDynamicKeyVBind(node)) {
+        // element has bindings with dynamic keys, which can possibly contain
+        // "type".
+        directiveToUse = V_MODEL_DYNAMIC
       } else {
         // text type
         __DEV__ && checkDuplicatedValue()