Signature generation roundtrip issue: SRTP multi-witness constraint on type member

[T-Gro]

Implementation:

module Lib

let inline RequireM< ^Witnesses, ^T 
    when (^Witnesses or ^T): (static member M : ^T -> string)> (x: ^T) : string = 
    ((^Witnesses or ^T): (static member M : ^T -> string) x)

type C(p:int) = 
    member x.P = p

type Witnesses() =
    static member M (x: C) : string = sprintf "M(C), x = %d" x.P
    static member M (x: int64) : string = sprintf "M(int64), x = %d" x

type StaticMethods =
    static member inline M< ^T when (Witnesses or ^T): (static member M: ^T -> string)> (x: ^T) : string =
        RequireM< Witnesses, ^T> (x)

Actual generated signature (partial):

val inline RequireM:
  x: ^T -> string when (^Witnesses or ^T) : (static member M: ^T -> string)
...
type StaticMethods =
    static member
      inline M: x: ^T -> string
                  when (Witnesses or ^T) : (static member M: ^T -> string)

Note: RequireM uses ^Witnesses (hat). StaticMethods.M uses Witnesses (no hat). Should be ^Witnesses.

Error on roundtrip compile:

error FS0340: The signature and implementation are not compatible because the declaration of the type parameter requires a constraint of the form (^Witnesses or ^T) : (static member M: ^T -> string)

Expected signature:

[<Class>]
type StaticMethods =
    static member inline M< ^T when (Witnesses or ^T) : (static member M: ^T -> string)> : x: ^T -> string

Verified: roundtrips successfully with explicit type param syntax.

[T-Gro]

Additional repro found by corpus sweep (also fixed by this change):

// impl
module Pos34
[<Sealed>]
type Foo<'bar>() =
    member inline _.Baz<'a> (x: 'a) = x

Before fix, generated sig had type application syntax that failed to parse (FS0010). The explicit type param declaration fix resolves this as well.