Confusing error message for use of old lambda syntax

[catamorphism]

fn f(v: ~[int]) {
  for v.each {|z| log(error, z); };
}

I used the old lambda syntax and got this error message:

/Users/TimChevalier/Scratch/f.rs:3:8: 3:34 error: mismatched types: expected `fn(&&int)` but found `fn()` (incorrect number of function parameters)
/Users/TimChevalier/Scratch/f.rs:3   for v.each {|z| log(error, z); };
                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/TimChevalier/Scratch/f.rs:3:8: 3:34 error: mismatched types: expected `fn(&&int) -> bool` but found `fn() -> bool` (incorrect number of function parameters)
/Users/TimChevalier/Scratch/f.rs:3   for v.each {|z| log(error, z); };
                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~

It took me a good 5 minutes to figure out what I was doing wrong there. Surely there could be a better error message for this.

[graydon]

I'm not sure what it would do here; the old syntax happens to parse as something completely different in the new syntax. I don't think there's much we can do to help if you put the || inside the { like this.

I'm going to close this one as WONTFIX but if you feel strongly, reopen.