Rollup merge of #88050 - Aaron1011:filename-hash-stable, r=michaelwoerister

Remove `HashStable` impls for `FileName` and `RealFileName`

These impls were unused, and incorrectly hashed the local
(non-remapped) path for `RealFileName::Remapped` (which would
break reproducible builds if these impls were used).

Author: GuillaumeGomez

compiler/rustc_span/src/lib.rs

@@ -157,7 +157,7 @@ scoped_tls::scoped_thread_local!(static SESSION_GLOBALS: SessionGlobals);
 // FIXME: We should use this enum or something like it to get rid of the
 // use of magic `/rust/1.x/...` paths across the board.
 #[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd)]
-#[derive(HashStable_Generic, Decodable)]
+#[derive(Decodable)]
 pub enum RealFileName {
     LocalPath(PathBuf),
     /// For remapped paths (namely paths into libstd that have been mapped
@@ -269,7 +269,7 @@ impl RealFileName {
 
 /// Differentiates between real files and common virtual files.
 #[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash)]
-#[derive(HashStable_Generic, Decodable, Encodable)]
+#[derive(Decodable, Encodable)]
 pub enum FileName {
     Real(RealFileName),
     /// Call to `quote!`.