Fixed E0528 label and unit test

src/librustc_typeck/check/_match.rs

@@ -248,9 +248,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
  } else if let Some(rest) = size.checked_sub(min_len) {
  (inner_ty, tcx.mk_array(inner_ty, rest))
  } else {
- span_err!(tcx.sess, pat.span, E0528,
- "pattern requires at least {} elements but array has {}",
- min_len, size);
+ struct_span_err!(tcx.sess, pat.span, E0528,
+ "pattern requires at least {} elements but array has {}",
+ min_len, size)
+ .span_label(pat.span,
+ &format!("pattern cannot match array of {} elements", size))
+ .emit();
  (inner_ty, tcx.types.err)
  }
  }

src/test/compile-fail/E0528.rs

@@ -13,7 +13,9 @@
 fn main() {
  let r = &[1, 2];
  match r {
- &[a, b, c, rest..] => { //~ ERROR E0528
+ &[a, b, c, rest..] => {
+ //~^ ERROR E0528
+ //~| NOTE pattern cannot match array of 2 elements
  }
  }
 }