diff --git a/compiler/rustc_smir/src/rustc_smir/mod.rs b/compiler/rustc_smir/src/rustc_smir/mod.rs
index 167a01ab7990c..0201df721f294 100644
--- a/compiler/rustc_smir/src/rustc_smir/mod.rs
+++ b/compiler/rustc_smir/src/rustc_smir/mod.rs
@@ -69,15 +69,13 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
 
     fn get_filename(&self, span: &Span) -> Filename {
         let tables = self.0.borrow();
-        opaque(
-            &tables
-                .tcx
-                .sess
-                .source_map()
-                .span_to_filename(tables[*span])
-                .display(rustc_span::FileNameDisplayPreference::Local)
-                .to_string(),
-        )
+        tables
+            .tcx
+            .sess
+            .source_map()
+            .span_to_filename(tables[*span])
+            .display(rustc_span::FileNameDisplayPreference::Local)
+            .to_string()
     }
 
     fn get_lines(&self, span: &Span) -> LineInfo {
diff --git a/compiler/stable_mir/src/lib.rs b/compiler/stable_mir/src/lib.rs
index 91f1066d7205a..5eb6a8a5e543e 100644
--- a/compiler/stable_mir/src/lib.rs
+++ b/compiler/stable_mir/src/lib.rs
@@ -110,7 +110,7 @@ pub enum ItemKind {
     Const,
 }
 
-pub type Filename = Opaque;
+pub type Filename = String;
 
 /// Holds information about an item in the crate.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]