Make local_path in RealFileName::Remapped Option to be removed in exported metadata

compiler/rustc_expand/src/base.rs

@@ -1073,7 +1073,9 @@ impl<'a> ExtCtxt<'a> {
         if !path.is_absolute() {
             let callsite = span.source_callsite();
             let mut result = match self.source_map().span_to_filename(callsite) {
-                FileName::Real(name) => name.into_local_path(),
+                FileName::Real(name) => name
+                    .into_local_path()
+                    .expect("attempting to resolve a file path in an external file"),
                 FileName::DocTest(path, _) => path,
                 other => {
                     return Err(self.struct_span_err(

compiler/rustc_expand/src/expand.rs

@@ -362,7 +362,9 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
     // make crate a first class expansion target instead.
     pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
         let file_path = match self.cx.source_map().span_to_filename(krate.span) {
-            FileName::Real(name) => name.into_local_path(),
+            FileName::Real(name) => name
+                .into_local_path()
+                .expect("attempting to resolve a file path in an external file"),
             other => PathBuf::from(other.to_string()),
         };
         let dir_path = file_path.parent().unwrap_or(&file_path).to_owned();

compiler/rustc_expand/src/proc_macro_server.rs

@@ -623,6 +623,7 @@ impl server::SourceFile for Rustc<'_> {
         match file.name {
             FileName::Real(ref name) => name
                 .local_path()
+                .expect("attempting to get a file path in an imported file in `proc_macro::SourceFile::path`")
                 .to_str()
                 .expect("non-UTF8 file path in `proc_macro::SourceFile::path`")
                 .to_string(),