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[TS] invalid TS emited for mutable structs #4453
Description
When targeting Typescript mutable fields on structs cause the struct to be wraped in FSharpRef<_> , but then the access to the field fails to compile
This happens only when there is mutable after val
[<Struct>]
type R =
val mutable X: float
new(x: float) = { X = x }
member this.IsEmpty() =
// emits invalid TS
// Property 'X' does not exist on type 'FSharpRef<Rt>'.
this.X < 0.0compiles to
export class R extends Record implements IEquatable<R>, IComparable<R> {
X: float64;
constructor(X: float64) {
super();
this.X = X;
}
}
export function R__IsEmpty(this$: FSharpRef<R>): boolean {
return this$.X < 0; // Property 'X' does not exist on type 'FSharpRef<Rt>'.
}why is FSharpRef<_> needed here?
Tested on 5.rc5 and in REPL
Activity
[TS] Fix invalid thisArg argument type in structs (fable-compiler#4453)
[TS/Python] Fix invalid `this` argument type in structs (fable-compil…
[TS/Python] Fix invalid `this` argument type in structs (fable-compil…
[TS/Python] Fix invalid `this` argument type in structs (#4453) (#4454)
goswinr commentedon Mar 30, 2026
thanks @ncave for the quick fix,
I tested 142afe4 .
this works for members, but still errors on
overridelikethis.ToString()still emits
FSharpRef<_>[TS/Python] Fix thisArg type for overloads in structs (#4453) (#4466)
ncave commentedon Mar 30, 2026
@goswinr Thanks for contributing the issue. Fixed in #4466.