A function that returns a class with a property getter is unusable via a declaration file (TS2611) #54879
Description
Bug Report
🔎 Search Terms
TS2611, declaration file, property getter
🕗 Version & Regression Information
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about TS2611, declaration files, property getters
⏯ Playground Link
This can't be completely reproduced in the Playground because it requires two separate projects. One to produce a .d.ts and another to attempt (and fail) to use it.
💻 Code
Complete and minimal code sample here: https://github.com/kring/ts2611-in-decl-files
You can reproduce it by cloning that repo and running npm install && npm run build.
To recreate it manually, define two projects, a and b, and use project references to link them up. Project a exports a class which is created by deriving from a class returned by a function, like this:
function functionReturningClass() {
return class ClassInsideFunction {
get r() {
return 7;
}
};
}
class Something extends functionReturningClass() {
override get r() {
return 8;
}
}
export default Something;(The above is in https://github.com/kring/ts2611-in-decl-files/blob/main/a/something.ts)
Now if we add another module that uses this to the same project, then it works great:
import Something from "./something.js";
const d = new Something();
console.log(d.r);(the above is in https://github.com/kring/ts2611-in-decl-files/blob/main/a/use-from-a.ts)
However, if we add identical code to another project that references this one, like this, then it no longer works anymore:
import Something from "../a/something.js";
const d = new Something();
console.log(d.r);(the above is from https://github.com/kring/ts2611-in-decl-files/blob/main/b/use-from-b.ts)
🙁 Actual behavior
TypeScript reports the following:
out/a/something.d.ts:7:9 - error TS2611: 'r' is defined as a property in class '{ readonly r: number; }', but is overridden here in 'Something' as an accessor.
7 get r(): number;
~
This happens because the generated .d.ts does in fact mix properties and accessors:
declare const Something_base: {
new (): {
readonly r: number;
};
};
declare class Something extends Something_base {
get r(): number;
}
export default Something;As far as I can tell, this makes the generated .d.ts file unusable.
🙂 Expected behavior
I expected no compiler error, probably because the TS compiler emitted an accessor in Something_base rather than a property. Or maybe because it didn't get hung on the mismatch in this scenario?
This was also previously observed here:
#41347 (comment)
Thank you for taking a look!