Object literals in output causing syntax errors

[jbt]

• Rollup Version: 2.36.0
• Operating System (or Browser): any
• Node Version (if applicable):
• Link to reproduction (IMPORTANT, read below): repl

I've started seeing non-tree-shakeable object literals appearing in my output as of 2.36.0 when the thing to which they were assigned is shaken away. But without the assignment, they're not interpreted as object literals and throw syntax errors.

Spotted this with .propTypes being applied to a React component as a default export which was being removed, but the prop types defintion was left in the output.

Seems to work fine with 2.35.1 so I guess it's related to #3919

repl link

Input:

export default function foo() {}

foo.propTypes = { foo: something() }

Expected Behavior

If foo gets tree-shaken then the non-tree-shakeable definition of propTypes shouldn't produce invalid output.

Actual Behavior

Output is just { foo: something() }; which on its own is invalid js because without the assignment it's not interpreted as an object literal

[lukastaegert]

Thanks for spotting! This was definitely an oversight on my part as this is a variation of an issue we already solved for other similar optimizations. Fix at #3921, will release once CI is clear.

[jbt]

Amazing, nice one!

[jbt]

Just tested my case with 2.36.1 and working perfectly now! Appreciate the quick fix 🙌