Crash on 5.4.0-dev.20231206

[ArnaudBarre]

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🕗 Version & Regression Information

It's working on 5.3
Here is the stacktrace, I hope it helps, I don't really have time to disect which part my codebase triggers this. Feel free to close if this not enough to understand the regression

TypeError: Cannot read properties of undefined (reading '0')
   at removeConstrainedTypeVariables (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:57118:33)
   at getUnionTypeWorker (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:57215:9)
   at getUnionType (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:57194:12)
   at createJsxAttributesTypeFromAttributesProperty (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:69288:216)
   at checkJsxAttributes (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:69353:12)
   at checkExpressionWorker (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:75700:16)
   at checkExpression (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:75557:32)
   at checkExpressionWithContextualType (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:75203:18)
   at resolveJsxOpeningLikeElement (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:72230:51)
   at resolveSignature (/Users/arnaud/git/carbon-calculator/node_modules/typescript/lib/tsc.js:72303:16)

⏯ Playground Link

No response

💻 Code

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🙁 Actual behavior

Crash

🙂 Expected behavior

No crash

Additional information about the issue

No response

[Andarist]

Does it crash on 5.4.0-dev.20231206 too?

[ArnaudBarre]

It crashes on 20231206 and 20231205, not on 5.3.2. Didn't try other versions

[Andarist]

removeConstrainedTypeVariables was introduced in #56515 . Could you confirm that 5.4.0-dev.20231130 works OK but 5.4.0-dev.20231201 is broken? Even with that confirmation - it might be hard to fix this without a repro case. If you'd be interested I could try to guide you on how to at least narrow it down to the file in which the problem occurs. With that information, you'd have an easier time dissecting this to a minimal repro case.

[ArnaudBarre]

Ok so yes it crashes starting on 20231201.
I ran the debugger and found the file, and after few try and errors I think this is this combination:

// .d.ts
declare global {
  interface String {
    upperFirst<T extends string>(this: T): Capitalize<T>;
  }
}

// display.ts
const displayEnum = (value: string) => value.toLowerCase().upperFirst();

// Component.tsx
<>{displayEnum("VALUE")}</> 

[jakebailey]

It's in the template, but you can also use https://www.npmjs.com/package/every-ts to narrow it down further.

I can't get your case to crash in the test suite, unfortunately.

[ArnaudBarre]

Ok this is the missing piece, the span before is strangely required:
Here is my mininal repro, I don't think my TS config should have an impact on the crash

declare global {
  interface String {
    upperFirst<T extends string>(this: T): Capitalize<T>;
  }
}

const displayEnum = (value: string) => value.toLowerCase().upperFirst();

console.log(
  <div>
    <span>Scope:</span> {displayEnum("VALUE")}
  </div>,
);

export {};