test coverage for mixed usage warning

Author: yyx990803

src/compiler/compile.js

@@ -621,7 +621,7 @@ function compileDirectives (attrs, options) {
           return attr.name === ':class' || attr.name === 'v-bind:class'
         })) {
           _.warn(
-            name + '="' + rawValue + '": Do not mix mustache interpolation ' +
+            'class="' + rawValue + '": Do not mix mustache interpolation ' +
             'and v-bind for "class" on the same element. Use one or the other.'
           )
         }

test/unit/specs/compiler/compile_spec.js

@@ -517,6 +517,17 @@ if (_.inBrowser) {
       expect(hasWarned(_, 'attribute interpolation is not allowed in Vue.js directives')).toBe(true)
     })
 
+    it('attribute interpolation: warn mixed usage with v-bind', function () {
+      new Vue({
+        el: el,
+        template: '<div class="{{a}}" :class="bcd"></div>',
+        data: {
+          a: 'hi'
+        }
+      })
+      expect(hasWarned(_, 'Do not mix mustache interpolation and v-bind')).toBe(true)
+    })
+
     it('warn directives on fragment instances', function () {
       new Vue({
         el: el,