string format specifier '{i:X4}' not working

[thautwarm]

let i = 123

$"\\u{i:X4}" # 
val it: string = "\u007B"

However it produces \u%P(X4) in 4.0.0-alpha-020...

[thautwarm]

workaround:

(sprintf "%4X" i).Replace(" ", "0")

printf in fable_modules works well.

[dbrattli]

FYI: This looks to be failing in Fable JS as well, please submit an issue to https://github.com/fable-compiler/Fable