}
fn all_constructors(cx: &MatchCheckCtxt, m: &Matrix, left_ty: ty::t) -> Vec<ctor> {
+ // This produces a list of all vector constructors that we would expect to appear
+ // in an exhaustive set of patterns. Because such a list would normally be infinite,
+ // we narrow it down to only those constructors that actually appear in the inspected
+ // column, plus, any that are missing and not covered by a pattern with a destructured slice.
fn vec_constructors(m: &Matrix) -> Vec<ctor> {
let max_vec_len = m.iter().map(|r| match r.get(0).node {
PatVec(ref before, _, ref after) => before.len() + after.len(),
_ => 0u
}).max().unwrap_or(0u);
- let contains_slice = m.iter().any(|r| match r.get(0).node {
- PatVec(_, ref slice, _) => slice.is_some(),
- _ => false
- });
- let lengths = iter::range_inclusive(0u, if contains_slice {
- max_vec_len
- } else {
- max_vec_len + 1
- });
- lengths.map(|len| vec(len)).collect()
+ let min_vec_len_with_slice = m.iter().map(|r| match r.get(0).node {
+ PatVec(ref before, Some(_), ref after) => before.len() + after.len(),
+ _ => max_vec_len + 1
+ }).min().unwrap_or(max_vec_len + 1);
+ let other_lengths = m.iter().map(|r| match r.get(0).node {
+ PatVec(ref before, _, ref after) => before.len() + after.len(),
+ _ => 0u
+ }).filter(|&len| len > min_vec_len_with_slice);
+ iter::range_inclusive(0u, min_vec_len_with_slice)
+ .chain(other_lengths)
+ .map(|len| vec(len))
+ .collect()
}
match ty::get(left_ty).sty {
--- /dev/null
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+ let mut x = &[1, 2, 3, 4];
+
+ let mut result = vec!();
+ loop {
+ x = match x {
+ [1, n, 3, ..rest] => {
+ result.push(n);
+ rest
+ }
+ [n, ..rest] => {
+ result.push(n);
+ rest
+ }
+ [] =>
+ break
+ }
+ }
+ assert!(result.as_slice() == [2, 4]);
+}