diff --git a/src/lib.rs b/src/lib.rs
index 25f61f7..d0660d4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -106,13 +106,16 @@
     }
 }
 
+// Returned by reference, so we can't easily wrap it.
+pub use imp::FileName;
+
 #[derive(Clone, PartialEq, Eq)]
 pub struct SourceFile(imp::SourceFile);
 
 impl SourceFile {
     /// Get the path to this source file as a string.
-    pub fn as_str(&self) -> &str {
-        self.0.as_str()
+    pub fn path(&self) -> &FileName {
+        self.0.path()
     }
 
     pub fn is_real(&self) -> bool {
@@ -120,15 +123,9 @@
     }
 }
 
-impl AsRef<str> for SourceFile {
-    fn as_ref(&self) -> &str {
-        self.0.as_ref()
-    }
-}
-
-impl PartialEq<str> for SourceFile {
-    fn eq(&self, other: &str) -> bool {
-        self.0.eq(other)
+impl AsRef<FileName> for SourceFile {
+    fn as_ref(&self) -> &FileName {
+        self.0.path()
     }
 }
 
diff --git a/src/stable.rs b/src/stable.rs
index 8b951e5..4bcaf6c 100644
--- a/src/stable.rs
+++ b/src/stable.rs
@@ -150,14 +150,23 @@
     }
 }
 
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct FileName(String);
+
+impl fmt::Display for FileName {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
 #[derive(Clone, PartialEq, Eq)]
 pub struct SourceFile {
-    name: String,
+    name: FileName,
 }
 
 impl SourceFile {
     /// Get the path to this source file as a string.
-    pub fn as_str(&self) -> &str {
+    pub fn path(&self) -> &FileName {
         &self.name
     }
 
@@ -167,22 +176,16 @@
     }
 }
 
-impl AsRef<str> for SourceFile {
-    fn as_ref(&self) -> &str {
-        self.as_str()
-    }
-}
-
-impl PartialEq<str> for SourceFile {
-    fn eq(&self, other: &str) -> bool {
-        self.as_ref() == other
+impl AsRef<FileName> for SourceFile {
+    fn as_ref(&self) -> &FileName {
+        self.path()
     }
 }
 
 impl fmt::Debug for SourceFile {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("SourceFile")
-            .field("path", &self.as_str())
+            .field("path", &self.path())
             .field("is_real", &self.is_real())
             .finish()
     }
@@ -299,7 +302,7 @@
             let cm = cm.borrow();
             let fi = cm.fileinfo(*self);
             SourceFile {
-                name: fi.name.clone(),
+                name: FileName(fi.name.clone()),
             }
         })
     }
diff --git a/src/unstable.rs b/src/unstable.rs
index 3f4ef63..f4d1a41 100644
--- a/src/unstable.rs
+++ b/src/unstable.rs
@@ -160,12 +160,28 @@
 }
 
 #[derive(Clone, PartialEq, Eq)]
-pub struct SourceFile(proc_macro::SourceFile);
+pub struct FileName(String);
+
+impl fmt::Display for FileName {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+// NOTE: We have to generate our own filename object here because we can't wrap
+// the one provided by proc_macro.
+#[derive(Clone, PartialEq, Eq)]
+pub struct SourceFile(proc_macro::SourceFile, FileName);
 
 impl SourceFile {
+    fn new(sf: proc_macro::SourceFile) -> Self {
+        let filename = FileName(sf.path().to_string());
+        SourceFile(sf, filename)
+    }
+
     /// Get the path to this source file as a string.
-    pub fn as_str(&self) -> &str {
-        self.0.as_str()
+    pub fn path(&self) -> &FileName {
+        &self.1
     }
 
     pub fn is_real(&self) -> bool {
@@ -173,15 +189,9 @@
     }
 }
 
-impl AsRef<str> for SourceFile {
-    fn as_ref(&self) -> &str {
-        self.0.as_ref()
-    }
-}
-
-impl PartialEq<str> for SourceFile {
-    fn eq(&self, other: &str) -> bool {
-        self.0.eq(other)
+impl AsRef<FileName> for SourceFile {
+    fn as_ref(&self) -> &FileName {
+        self.path()
     }
 }
 
@@ -209,7 +219,7 @@
     }
 
     pub fn source_file(&self) -> SourceFile {
-        SourceFile(self.0.source_file())
+        SourceFile::new(self.0.source_file())
     }
 
     pub fn start(&self) -> LineColumn {