<h3 dir="auto">Version</h3>
<p dir="auto">2.5.3</p>
<h3 dir="auto">Reproduction link</h3>
<p dir="auto"><a href="https://vuejs.org/v2/guide/render-function.html#Template-Compilation" rel="nofollow">https://vuejs.org/v2/guide/render-function.html#Template-Compilation</a></p>
<p dir="auto">(Alternative reproduction on jsfiddle: <a href="https://jsfiddle.net/Linusborg/pqbppg7a/" rel="nofollow">https://jsfiddle.net/Linusborg/pqbppg7a/</a>)</p>
<h3 dir="auto">Steps to reproduce</h3>
<ol dir="auto">
<li>Paste the following piece of HTML into the textarea of the linked documentation chapter above.</li>
</ol>
<div class="highlight highlight-text-html-basic notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="&lt;input type=&quot;text&quot; v-bind:value=&quot;message&quot; v-model=&quot;message&quot;&gt;"><pre class="notranslate"><span class="pl-kos">&lt;</span><span class="pl-ent">input</span> <span class="pl-c1">type</span>="<span class="pl-s">text</span>" <span class="pl-c1">v-bind:value</span>="<span class="pl-s">message</span>" <span class="pl-c1">v-model</span>="<span class="pl-s">message</span>"<span class="pl-kos">&gt;</span></pre></div>
<ol start="2" dir="auto">
<li>Inspect the code of the created render function, especially the <code class="notranslate">domProps</code> options:</li>
</ol>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="domProps: {
  &quot;value&quot;: message,
  &quot;value&quot;: (message)
},"><pre class="notranslate"><span class="pl-s1">domProps</span>: <span class="pl-kos">{</span>
  <span class="pl-s">"value"</span>: <span class="pl-s1">message</span><span class="pl-kos">,</span>
  <span class="pl-s">"value"</span>: <span class="pl-kos">(</span><span class="pl-s1">message</span><span class="pl-kos">)</span>
<span class="pl-kos">}</span><span class="pl-kos">,</span></pre></div>
<h3 dir="auto">What is expected?</h3>
<p dir="auto">The code should run in all browsers, or throw an error or warning.</p>
<h3 dir="auto">What is actually happening?</h3>
<p dir="auto">IE11 throws an error: "duplicate properties not allowed in strict mode".</p>
<hr>
<p dir="auto">I realize that using both v-bind:value and v-model on an input  is not recommended or even sensible, but it doesn't throw an error or warning when done in modern browsers, and doesn't create any problems if the expression is the same for both, so it can easily be overlooked when added accidentally.</p>
<p dir="auto">Uglify also doesn't help - it doesn't remove the first occurrence that would otherwise be "overwritten" by the second in modern browsers.</p>
<p dir="auto">So what would be a sensible solution? I'm not sure.</p>
<ul dir="auto">
<li>We could adjust the <a href="https://github.com/vuejs/vue/blob/dev/src/compiler/codegen/index.js#L488-L495">codegen of domProps</a> to check for a double occurence of the <code class="notranslate">value</code> prop on elements of type "input" and drop all but the last occurrence. Possible Problem: performance?</li>
<li>We could log a warning to console (how to deal with that in vue-loader?)</li>
<li>We could throw an error, forcing the user to choose between the two (breaking change)</li>
<li>we could improve awareness by adding a warning to docs and a rule to eslint-plugin-vue?</li>
</ul>
<h3 dir="auto">Version</h3>
<p dir="auto">2.6.10</p>
<h3 dir="auto">Reproduction link</h3>
<p dir="auto"><a href="https://codesandbox.io/s/quizzical-hooks-flxdp" rel="nofollow">https://codesandbox.io/s/quizzical-hooks-flxdp</a></p>
<h3 dir="auto">Steps to reproduce</h3>
<p dir="auto">No steps. Just check out the reproduction.</p>
<h3 dir="auto">What is expected?</h3>
<p dir="auto">The class styles in App.vue to be applied on the functional SFC.</p>
<h3 dir="auto">What is actually happening?</h3>
<p dir="auto">Parent class is added to the classlist of child, but the css is not generated for the class.</p>
<hr>
<p dir="auto">If you remove the 'scoped' keyword from functional component, then all the styles are applied. But the need is to use this with scoped styles, as with normal components is done.</p>