diff --git a/naga/src/span.rs b/naga/src/span.rs
index b098bf83e5..0256e19dc4 100644
--- a/naga/src/span.rs
+++ b/naga/src/span.rs
@@ -379,7 +379,7 @@ impl<T> SpanProvider<T> for UniqueArena<T> {
 
 /// Convenience trait for [`Result`], adding a [`MapErrWithSpan::map_err_inner`]
 /// mapping to [`WithSpan::and_then`].
-pub trait MapErrWithSpan<E, E2>: Sized {
+pub(crate) trait MapErrWithSpan<E, E2>: Sized {
     /// The returned output type.
     type Output: Sized;