Pattern discard allowed for union case that takes no data

[NinoFloris]

Match discards aren't type checked against case

    type X = X 

    let test() =
        match X with
        | X _ -> () // No error X doesn't have arguments

[vzarytovskii]

Duplicate of #10204 and #1592, which are not considered bugs, according to @dsyme.
Should probably be a lang suggestion instead?

[edgarfgp]

It always triggers me that when refactoring a DU my code still still compilers where I’m using _ in pattern matching 😟. An error, warning might help here ?

[dsyme]

Things have changed a bit since 2016, and we now are more inclined to emit new informationals and warnings, protected by a /langversion switch.

So I'd definitely be ok with emitting at least an informational, and possibly a warning for this case.

[NinoFloris]

Was this originally missed or was this intended as a source compatibility feature? (being able to drop data in select scenarios)

Do informational diags pop up in IDEs? I wouldn't mind a warning tbh.

[dsyme]

Was this originally missed or was this intended as a source compatibility feature? (being able to drop data in select scenarios)

It crept in somewhere along the way

Do informational diags pop up in IDEs?

Yes they show, but very light decorations