make_mut_slice

1 files changed, 4 insertions, 11 deletions

diff --git a/crates/ra_hir/src/util.rs b/crates/ra_hir/src/util.rs
index 46f423c91..0095ee45d 100644
--- a/crates/ra_hir/src/util.rs
+++ b/crates/ra_hir/src/util.rs
@@ -4,16 +4,9 @@ use std::sync::Arc;
 
 /// Helper for mutating `Arc<[T]>` (i.e. `Arc::make_mut` for Arc slices).
 /// The underlying values are cloned if there are other strong references.
-pub(crate) fn make_mut_arc_slice<T: Clone, R>(
-    a: &mut Arc<[T]>,
-    f: impl FnOnce(&mut [T]) -> R,
-) -> R {
-    if let Some(s) = Arc::get_mut(a) {
-        f(s)
-    } else {
-        let mut v = a.to_vec();
-        let r = f(&mut v);
-        *a = Arc::from(v);
-        r
+pub(crate) fn make_mut_slice<T: Clone>(a: &mut Arc<[T]>) -> &mut [T] {
+    if Arc::get_mut(a).is_none() {
+        *a = a.iter().cloned().collect();
     }
+    Arc::get_mut(a).unwrap()
 }