feature gate iscovariant impl

unicode-org · Nov 10, 2021 · a61281e · a61281e
1 parent f056bc4
commit a61281e
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/utils/yoke/src/is_covariant.rs b/utils/yoke/src/is_covariant.rs
@@ -113,6 +113,7 @@ pub unsafe trait IsCovariant<'a>: 'a {}
 unsafe impl<'a> IsCovariant<'a> for () {}
 
 unsafe impl<'a> IsCovariant<'a> for str {}
+#[cfg(feature = "alloc")]
 unsafe impl<'a> IsCovariant<'a> for String {}
 
 unsafe impl<'a, T: IsCovariant<'a>> IsCovariant<'a> for Option<T> {}