Repro steps

let y = box 1

Expected behavior

y should be of type obj

Actual behavior

y has type obj | null

Known workarounds

let y = 
    match box 1 with
    | NonNull i -> i
    | Null -> failwith "never fails"

Related information

Provide any related information (optional):

• Windows 11
• dotnet 9.0.0-rc.1.24431.7