In Typescript 5.2 were added type arguments placeholders. That is, if you have something like

declare function f<A, B, C>(x: A, y: B, z: C): C

You can write f<_, _, 1>("",[],1) to specify you expect C to be 1 (it would else be inferred as number), but you let the compiler infer A and B.

I have Typescript 5.5, but when I write the above, I get an error : Cannot find name '_'.

Any idea what’s going on ?