Unfelpful error when trying to call member function as free function

[ChrisJefferson]

I just spent far too long trying to figure out the problem with the following (reduced) code

struct X { i: isize }

impl X {
    fn a(&self, i: usize)
    { }

    fn b(&self)
    { a(self, 2) }
}

Which produces the error:

    Checking playground v0.0.1 (/playground)
error[E0425]: cannot find function `a` in this scope
 --> src/lib.rs:8:7
  |
8 |     { a(self, 2) }
  |       ^ not found in this scope

error: aborting due to previous error

For more information about this error, try `rustc --explain E0425`.
error: could not compile `playground`.

To learn more, run the command again with --verbose.

While I don't expect the code to compile, perhaps mention when trying to call a(self,...) that I should be calling self.a(...)?

[ChrisJefferson]

Thanks!