Fix 238 - Generic use of member constraint solved to record field causes crash

[dsyme]

Fix #238

We were missing a constraint assertion (to force the return type of a record solution to be equal to the return type in the static member constraint being solved)

[latkin]

👍

[latkin]

Thumbs-upped too soon. This doesn't consider setters for mutable record fields, which return unit.

Below previously worked, now fails.

type Foo = { mutable Y : int }
let inline setY (x:^T) (y:int) = (^T : (member set_Y : int -> unit) (x, y))
let x = { Y = 0 }

// error FS0001: The type 'unit' does not match the type 'int'
setY x 1

[dsyme]

Thanks! Which test was that?

[latkin]

tests\fsharp\core\subtype\test.fsx

[dsyme]

OK, fix now updated, should be good to go.