Merge pull request #1859 from porglezomp-misc/master

Fix #1858 - "Don't erase a use with attributes attached"

Author: nrc

src/imports.rs

@@ -157,12 +157,8 @@ fn rewrite_view_path_prefix(
 }
 
 impl Rewrite for ast::ViewPath {
-    // Returns an empty string when the ViewPath is empty (like foo::bar::{})
     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
         match self.node {
-            ast::ViewPath_::ViewPathList(_, ref path_list) if path_list.is_empty() => {
-                Some(String::new())
-            }
             ast::ViewPath_::ViewPathList(ref path, ref path_list) => {
                 rewrite_use_list(shape, path, path_list, self.span, context)
             }
@@ -250,13 +246,27 @@ impl<'a> FmtVisitor<'a> {
         self.last_pos = pos_after_last_use_item;
     }
 
-    pub fn format_import(&mut self, vis: &ast::Visibility, vp: &ast::ViewPath, span: Span) {
+    pub fn format_import(
+        &mut self,
+        vis: &ast::Visibility,
+        vp: &ast::ViewPath,
+        span: Span,
+        attrs: &[ast::Attribute],
+    ) {
         let vis = utils::format_visibility(vis);
         // 4 = `use `, 1 = `;`
         let rw = Shape::indented(self.block_indent, self.config)
             .offset_left(vis.len() + 4)
             .and_then(|shape| shape.sub_width(1))
-            .and_then(|shape| vp.rewrite(&self.get_context(), shape));
+            .and_then(|shape| match vp.node {
+                // If we have an empty path list with no attributes, we erase it
+                ast::ViewPath_::ViewPathList(_, ref path_list)
+                    if path_list.is_empty() && attrs.is_empty() =>
+                {
+                    Some("".into())
+                }
+                _ => vp.rewrite(&self.get_context(), shape),
+            });
         match rw {
             Some(ref s) if s.is_empty() => {
                 // Format up to last newline
@@ -385,7 +395,7 @@ impl<'a> Ord for ImportItem<'a> {
 }
 
 // Pretty prints a multi-item import.
-// Assumes that path_list.len() > 0.
+// If the path list is empty, it leaves the braces empty.
 fn rewrite_use_list(
     shape: Shape,
     path: &ast::Path,
@@ -403,7 +413,10 @@ fn rewrite_use_list(
     ));
 
     match path_list.len() {
-        0 => unreachable!(),
+        0 => {
+            return rewrite_path(context, PathContext::Import, None, path, shape)
+                .map(|path_str| format!("{}::{{}}", path_str));
+        }
         1 => return Some(rewrite_single_use_list(path_str, &path_list[0])),
         _ => (),
     }

src/visitor.rs

@@ -293,7 +293,7 @@ impl<'a> FmtVisitor<'a> {
 
         match item.node {
             ast::ItemKind::Use(ref vp) => {
-                self.format_import(&item.vis, vp, item.span);
+                self.format_import(&item.vis, vp, item.span, &item.attrs);
             }
             ast::ItemKind::Impl(..) => {
                 self.format_missing_with_indent(source!(self, item.span).lo);

tests/source/imports.rs

@@ -72,3 +72,7 @@ use ::*;
 // spaces used to cause glob imports to disappear (#1356)
 use super:: * ;
 use foo::issue_1356:: * ;
+
+// We shouldn't remove imports which have attributes attached (#1858)
+#[cfg(unix)]
+use self::unix::{};

tests/target/imports.rs

@@ -67,3 +67,7 @@ use ::*;
 // spaces used to cause glob imports to disappear (#1356)
 use super::*;
 use foo::issue_1356::*;
+
+// We shouldn't remove imports which have attributes attached (#1858)
+#[cfg(unix)]
+use self::unix::{};