Function check_rvalue

fn check_rvalue<'tcx>(
    cx: &LateContext<'tcx>,
    body: &Body<'tcx>,
    def_id: DefId,
    rvalue: &Rvalue<'tcx>,
    span: Span,
    msrv: Msrv,
) -> Result<(), (Span, Cow<'static, str>)>