TS 3 only - 'You cannot rename this element' - while renaming discriminated unions

[smith-chris]

Appears on:

• VSCode + typescript@3.0.1, typescript@3.1.0-dev.20180804 (i have VSCode configured to use global TS)
• insiders VSCode install without extensions (1.26.0-insider)

Doesn't appear on:

• VSCode + typescript@2.9.2 (and probs all below)

Exact commit to replicate it on (src/store/game.ts):
https://github.com/smith-chris/poke/tree/b77d0f78d2e3700bf45e5c7ab3a9a4055ae26cf5

I think video explains it best:
https://vimeo.com/283216196

I'm filing it in typescript repo as the bug seems to be independent of VSCode version but dependent on TS version. I looked at last 30 days issues and didn't find related one.

I hope that's enough information. Big thanks for all the work on TypeScript! 👏 I'm loving it

Cheers,
Chris

TypeScript Version: 3.1.0-dev.201xxxxx

Search Terms:

Code

// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.

Expected behavior:

Actual behavior:

Playground Link:

Related Issues:

This was changed in #24477 (fixing #16275).
The problem is that find-all-references on a string literal will find all occurrences of that string regardless of context. Semantic renaming of strings would probably require a string enum (usable today) or #1579. Currently, even if we allowed renaming strings it wouldn't be much better than a textual rename of "foo" (quotes included).

Think we should wait until we have better plans for how to rename string literals in a way better than ctrl-F does.

Related: #5602, #9257