2 files changed, 5 insertions, 3 deletions
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 7357cebf62e..1f4578c08a3 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -335,8 +335,8 @@ impl fmt::Display for FileNameDisplay<'_> {
     }
 }
 
-impl FileNameDisplay<'_> {
-    pub fn to_string_lossy(&self) -> Cow<'_, str> {
+impl<'a> FileNameDisplay<'a> {
+    pub fn to_string_lossy(&self) -> Cow<'a, str> {
         match self.inner {
             FileName::Real(ref inner) => inner.to_string_lossy(self.display_pref),
             _ => Cow::from(format!("{}", self)),
@@ -1153,7 +1153,7 @@ impl FromStr for SourceFileHashAlgorithm {
 }
 
 /// The hash of the on-disk source file used for debug info.
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
 #[derive(HashStable_Generic, Encodable, Decodable)]
 pub struct SourceFileHash {
     pub kind: SourceFileHashAlgorithm,
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index 44aa9f72809..020ae3ad0c7 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -1099,6 +1099,8 @@ impl FilePathMapping {
     /// the path was affected by the mapping.
     pub fn map_prefix(&self, path: PathBuf) -> (PathBuf, bool) {
         if path.as_os_str().is_empty() {
+            // Exit early if the path is empty and therefore there's nothing to remap.
+            // This is mostly to reduce spam for `RUSTC_LOG=[remap_path_prefix]`.
             return (path, false);
         }