From 31d9cc3833a30b0cd4c1554102402af68eebeeef Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Fri, 23 Dec 2016 02:16:31 +0000
Subject: [PATCH] Fix import resolution bug and fold all idents in the AST.

---
 src/librustc_resolve/resolve_imports.rs |  3 +--
 src/libsyntax/fold.rs                   | 29 ++++++++++++-------------
 src/test/run-pass/issue-38556.rs        | 22 +++++++++++++++++++
 3 files changed, 37 insertions(+), 17 deletions(-)
 create mode 100644 src/test/run-pass/issue-38556.rs

diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index 8bc0bfb41ff75..5972f2d87c44c 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.rs
@@ -128,6 +128,7 @@ impl<'a> NameResolution<'a> {
 impl<'a> Resolver<'a> {
     fn resolution(&self, module: Module<'a>, ident: Ident, ns: Namespace)
                   -> &'a RefCell<NameResolution<'a>> {
+        let ident = ident.unhygienize();
         *module.resolutions.borrow_mut().entry((ident, ns))
                .or_insert_with(|| self.arenas.alloc_name_resolution())
     }
@@ -141,7 +142,6 @@ impl<'a> Resolver<'a> {
                                    ignore_unresolved_invocations: bool,
                                    record_used: Option<Span>)
                                    -> Result<&'a NameBinding<'a>, Determinacy> {
-        let ident = ident.unhygienize();
         self.populate_module_if_necessary(module);
 
         let resolution = self.resolution(module, ident, ns)
@@ -307,7 +307,6 @@ impl<'a> Resolver<'a> {
                       ns: Namespace,
                       binding: &'a NameBinding<'a>)
                       -> Result<(), &'a NameBinding<'a>> {
-        let ident = ident.unhygienize();
         self.update_resolution(module, ident, ns, |this, resolution| {
             if let Some(old_binding) = resolution.binding {
                 if binding.is_glob_import() {
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index b3753e3e977e3..6f93819727598 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -302,23 +302,22 @@ pub fn noop_fold_view_path<T: Folder>(view_path: P<ViewPath>, fld: &mut T) -> P<
     view_path.map(|Spanned {node, span}| Spanned {
         node: match node {
             ViewPathSimple(ident, path) => {
-                ViewPathSimple(ident, fld.fold_path(path))
+                ViewPathSimple(fld.fold_ident(ident), fld.fold_path(path))
             }
             ViewPathGlob(path) => {
                 ViewPathGlob(fld.fold_path(path))
             }
             ViewPathList(path, path_list_idents) => {
-                ViewPathList(fld.fold_path(path),
-                             path_list_idents.move_map(|path_list_ident| {
-                                Spanned {
-                                    node: PathListItem_ {
-                                        id: fld.new_id(path_list_ident.node.id),
-                                        rename: path_list_ident.node.rename,
-                                        name: path_list_ident.node.name,
-                                    },
-                                    span: fld.new_span(path_list_ident.span)
-                                }
-                             }))
+                let path = fld.fold_path(path);
+                let path_list_idents = path_list_idents.move_map(|path_list_ident| Spanned {
+                    node: PathListItem_ {
+                        id: fld.new_id(path_list_ident.node.id),
+                        rename: path_list_ident.node.rename.map(|ident| fld.fold_ident(ident)),
+                        name: fld.fold_ident(path_list_ident.node.name),
+                    },
+                    span: fld.new_span(path_list_ident.span)
+                });
+                ViewPathList(path, path_list_idents)
             }
         },
         span: fld.new_span(span)
@@ -345,7 +344,7 @@ pub fn noop_fold_arm<T: Folder>(Arm {attrs, pats, guard, body}: Arm, fld: &mut T
 pub fn noop_fold_ty_binding<T: Folder>(b: TypeBinding, fld: &mut T) -> TypeBinding {
     TypeBinding {
         id: fld.new_id(b.id),
-        ident: b.ident,
+        ident: fld.fold_ident(b.ident),
         ty: fld.fold_ty(b.ty),
         span: fld.new_span(b.span),
     }
@@ -673,7 +672,7 @@ pub fn noop_fold_ty_param<T: Folder>(tp: TyParam, fld: &mut T) -> TyParam {
             .collect::<Vec<_>>()
             .into(),
         id: fld.new_id(id),
-        ident: ident,
+        ident: fld.fold_ident(ident),
         bounds: fld.fold_bounds(bounds),
         default: default.map(|x| fld.fold_ty(x)),
         span: span
@@ -1088,7 +1087,7 @@ pub fn noop_fold_pat<T: Folder>(p: P<Pat>, folder: &mut T) -> P<Pat> {
                 let fs = fields.move_map(|f| {
                     Spanned { span: folder.new_span(f.span),
                               node: ast::FieldPat {
-                                  ident: f.node.ident,
+                                  ident: folder.fold_ident(f.node.ident),
                                   pat: folder.fold_pat(f.node.pat),
                                   is_shorthand: f.node.is_shorthand,
                               }}
diff --git a/src/test/run-pass/issue-38556.rs b/src/test/run-pass/issue-38556.rs
new file mode 100644
index 0000000000000..f6f334f650b24
--- /dev/null
+++ b/src/test/run-pass/issue-38556.rs
@@ -0,0 +1,22 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub struct Foo;
+
+macro_rules! reexport {
+    () => { use Foo as Bar; }
+}
+
+reexport!();
+
+fn main() {
+    use Bar;
+    fn f(_: Bar) {}
+}