message: Update syscall FIXME to include note about 'wrong' types.
diff: @@ -116,10 +116,14 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  // FIXME: The libc syscall() function is a variadic function.
  // It's valid to call it with more arguments than a syscall
  // needs, so none of these syscalls should use check_arg_count.
  - // However, depending on the calling convention it might depend
  - // on the type and size of the arguments whether a call with
  - // the wrong number of arguments (or types) is valid or not.
  + // It's even valid to call it with the wrong type of arguments,
  + // as long as they'd end up in the same place with the calling
  + // convention used. (E.g. using a `usize` instead of a pointer.)
  + // It's not directly clear which number, size, and type of arguments
  + // are acceptable in which cases and which aren't. (E.g. some
  + // types might take up the space of two registers.)
  // So this needs to be researched first.
  +
  let sys_getrandom = this
  .eval_libc("SYS_getrandom")?
  .to_machine_usize(this)?;
  