pattern: fix compilation

This fixes compilation when the 'pattern' feature
is enabled. This wasn't previously tested since it
is a nightly only feature. But in this commit, we
add it to CI explicitly.

PR #772

Author: Luro02

.github/workflows/ci.yml

@@ -151,6 +151,11 @@ jobs:
         cd bench
         ./run rust --no-run --verbose
 
+    - if: matrix.build == 'nightly'
+      name: Run tests with pattern feature
+      run: |
+        cargo test --test default --no-default-features --features 'std pattern unicode-perl'
+
   rustfmt:
     name: rustfmt
     runs-on: ubuntu-18.04

src/pattern.rs

@@ -1,7 +1,8 @@
 use std::str::pattern::{Pattern, SearchStep, Searcher};
 
-use re_unicode::{Matches, Regex};
+use crate::re_unicode::{Matches, Regex};
 
+#[derive(Debug)]
 pub struct RegexSearcher<'r, 't> {
     haystack: &'t str,
     it: Matches<'r, 't>,