Warning when emitting custom event on template

[henriqemalheiros]

Version

2.6.0

Reproduction link

https://github.com/henriqemalheiros/vue-bug-report-event-emit-template

Steps to reproduce

• Clone the repo;
• Run yarn install;
• Run yarn run serve;
• Open http://localhost:8080/;
• Open browser console;
• Click on "Click me ($emit on method)";
• "custom click triggered" is printed on the console;
• Click on "Click me ($emit on template)";
• "custom click triggered" is printed on the console;
• "[Vue warn]: Property or method "then" is not defined on the instance but referenced during render." is also printed on the console.

What is expected?

No warning should be thrown.

What is actually happening?

A warning is thrown.

---

Maybe related to #8297.

[yyx990803]

Just a note - please avoid build setups when the bug can easily be reproduced using a simple jsfiddle or codepen.

[henriqemalheiros]

I tried, but the warning wasn't reproducible without a build setup.

[jvbianchi]

There is a reproduction in #9419 (duplicated issue)