Rename of a `member __.M()` self identifier silently corrupts the code

[xperiandri]

type RenameTest() =
    member __.TestMethod() = "Hello, World!"
    member __.TestMethodDoubleUnderscore() = __.TestMethod()

Pressing F2 on the __ in member __.TestMethodDoubleUnderscore() does nothing — no rename session starts. Pressing F2 on the __ in the body does start one, but it rewrites only the body occurrence and leaves member __. untouched, producing code that no longer compiles.

this, self and _ all rename correctly; only __ is affected. FCS reports the uses of the __ value but not its declaration, so the rename never sees the declaration to rewrite.