Auto merge of #44940 - philipc:remap-path, r=michaelwoerister

Don't use remapped path when loading modules and include files

Fixes bug reported in https://github.com/rust-lang/rust/issues/41555#issuecomment-327866056.

cc @michaelwoerister

4 files changed, 25 insertions, 9 deletions

diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index cd4a6f921fe..efaa5e5e3da 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -162,9 +162,21 @@ impl CodeMap {
         let start_pos = self.next_start_pos();
         let mut files = self.files.borrow_mut();
 
+        // The path is used to determine the directory for loading submodules and
+        // include files, so it must be before remapping.
+        // Note that filename may not be a valid path, eg it may be `<anon>` etc,
+        // but this is okay because the directory determined by `path.pop()` will
+        // be empty, so the working directory will be used.
+        let unmapped_path = PathBuf::from(filename.clone());
+
         let (filename, was_remapped) = self.path_mapping.map_prefix(filename);
-        let filemap =
-            Rc::new(FileMap::new(filename, was_remapped, src, Pos::from_usize(start_pos)));
+        let filemap = Rc::new(FileMap::new(
+            filename,
+            was_remapped,
+            unmapped_path,
+            src,
+            Pos::from_usize(start_pos),
+        ));
 
         files.push(filemap.clone());
 
@@ -216,6 +228,7 @@ impl CodeMap {
         let filemap = Rc::new(FileMap {
             name: filename,
             name_was_remapped,
+            unmapped_path: None,
             crate_of_origin,
             src: None,
             src_hash,
@@ -342,7 +355,12 @@ impl CodeMap {
     }
 
     pub fn span_to_filename(&self, sp: Span) -> FileName {
-        self.lookup_char_pos(sp.lo()).file.name.to_string()
+        self.lookup_char_pos(sp.lo()).file.name.clone()
+    }
+
+    pub fn span_to_unmapped_path(&self, sp: Span) -> PathBuf {
+        self.lookup_char_pos(sp.lo()).file.unmapped_path.clone()
+            .expect("CodeMap::span_to_unmapped_path called for imported FileMap?")
     }
 
     pub fn span_to_lines(&self, sp: Span) -> FileLinesResult {
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 6e7a8203b61..614c4a10e6d 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -35,7 +35,6 @@ use visit::Visitor;
 
 use std::collections::HashMap;
 use std::mem;
-use std::path::PathBuf;
 use std::rc::Rc;
 
 macro_rules! expansions {
@@ -200,7 +199,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         self.cx.crate_root = std_inject::injected_crate_name(&krate);
         let mut module = ModuleData {
             mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
-            directory: PathBuf::from(self.cx.codemap().span_to_filename(krate.span)),
+            directory: self.cx.codemap().span_to_unmapped_path(krate.span),
         };
         module.directory.pop();
         self.cx.current_expansion.module = Rc::new(module);
@@ -952,8 +951,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                         module.directory.push(&*item.ident.name.as_str());
                     }
                 } else {
-                    let mut path =
-                        PathBuf::from(self.cx.parse_sess.codemap().span_to_filename(inner));
+                    let mut path = self.cx.parse_sess.codemap().span_to_unmapped_path(inner);
                     let directory_ownership = match path.file_name().unwrap().to_str() {
                         Some("mod.rs") => DirectoryOwnership::Owned,
                         _ => DirectoryOwnership::UnownedViaMod(false),
diff --git a/src/libsyntax/ext/source_util.rs b/src/libsyntax/ext/source_util.rs
index 18a262d139a..86657e675b2 100644
--- a/src/libsyntax/ext/source_util.rs
+++ b/src/libsyntax/ext/source_util.rs
@@ -197,7 +197,7 @@ fn res_rel_file(cx: &mut ExtCtxt, sp: syntax_pos::Span, arg: &Path) -> PathBuf {
     // after macro expansion (that is, they are unhygienic).
     if !arg.is_absolute() {
         let callsite = sp.source_callsite();
-        let mut path = PathBuf::from(&cx.codemap().span_to_filename(callsite));
+        let mut path = cx.codemap().span_to_unmapped_path(callsite);
         path.pop();
         path.push(arg);
         path
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index d5ba4b54d90..65dabe98a06 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -525,7 +525,7 @@ impl<'a> Parser<'a> {
         if let Some(directory) = directory {
             parser.directory = directory;
         } else if parser.span != syntax_pos::DUMMY_SP {
-            parser.directory.path = PathBuf::from(sess.codemap().span_to_filename(parser.span));
+            parser.directory.path = sess.codemap().span_to_unmapped_path(parser.span);
             parser.directory.path.pop();
         }