diff --git a/rust/hg-core/src/filepatterns.rs b/rust/hg-core/src/filepatterns.rs
--- a/rust/hg-core/src/filepatterns.rs
+++ b/rust/hg-core/src/filepatterns.rs
@@ -8,7 +8,7 @@
 //! Handling of Mercurial-specific patterns.
 
 use crate::{
-    utils::{files::get_path_from_bytes, SliceExt},
+    utils::{concat, files::get_path_from_bytes, SliceExt},
     LineNumber, PatternError, PatternFileError,
 };
 use lazy_static::lazy_static;
@@ -158,20 +158,20 @@
             if pattern[0] == b'^' {
                 return pattern.to_owned();
             }
-            [&b".*"[..], pattern].concat()
+            concat(&[b".*", pattern])
         }
         PatternSyntax::Path | PatternSyntax::RelPath => {
             if pattern == b"." {
                 return vec![];
             }
-            [&escape_pattern(pattern), &b"(?:/|$)"[..]].concat()
+            concat(&[&escape_pattern(pattern), b"(?:/|$)"])
         }
         PatternSyntax::RootFiles => {
             let mut res = if pattern == b"." {
                 vec![]
             } else {
                 // Pattern is a directory name.
-                [&escape_pattern(pattern), &b"/"[..]].concat()
+                concat(&[&escape_pattern(pattern), b"/"])
             };
 
             // Anything after the pattern must be a non-directory.
@@ -181,14 +181,14 @@
         PatternSyntax::RelGlob => {
             let glob_re = glob_to_re(pattern);
             if let Some(rest) = glob_re.drop_prefix(b"[^/]*") {
-                [&b".*"[..], rest, globsuffix].concat()
+                concat(&[b".*", rest, globsuffix])
             } else {
-                [&b"(?:|.*/)"[..], &glob_re, globsuffix].concat()
+                concat(&[b"(?:|.*/)", &glob_re, globsuffix])
             }
         }
         PatternSyntax::Glob
         | PatternSyntax::RootGlob => {
-            [&glob_to_re(pattern), globsuffix].concat()
+            concat(&[&glob_to_re(pattern), globsuffix])
         }
     }
 }
diff --git a/rust/hg-core/src/utils.rs b/rust/hg-core/src/utils.rs
--- a/rust/hg-core/src/utils.rs
+++ b/rust/hg-core/src/utils.rs
@@ -37,6 +37,10 @@
     }
 }
 
+pub fn concat(slices: &[&[u8]]) -> Vec<u8> {
+    slices.concat()
+}
+
 pub trait SliceExt {
     fn trim_end(&self) -> &Self;
     fn trim_start(&self) -> &Self;