From 9273a724209849be96ded894f8eed5300b4daa1f Mon Sep 17 00:00:00 2001
From: Seiichi Uchida <seuchida@gmail.com>
Date: Sun, 4 Feb 2018 12:07:51 +0900
Subject: [PATCH 1/2] Add tests for reorder_extern_crates

---
 tests/source/configs/reorder_extern_crates/false.rs | 11 +++++++++++
 tests/source/configs/reorder_extern_crates/true.rs  | 11 +++++++++++
 tests/target/configs/reorder_extern_crates/false.rs | 11 +++++++++++
 tests/target/configs/reorder_extern_crates/true.rs  | 11 +++++++++++
 4 files changed, 44 insertions(+)
 create mode 100644 tests/source/configs/reorder_extern_crates/false.rs
 create mode 100644 tests/source/configs/reorder_extern_crates/true.rs
 create mode 100644 tests/target/configs/reorder_extern_crates/false.rs
 create mode 100644 tests/target/configs/reorder_extern_crates/true.rs

diff --git a/tests/source/configs/reorder_extern_crates/false.rs b/tests/source/configs/reorder_extern_crates/false.rs
new file mode 100644
index 00000000000..6bef132e5c3
--- /dev/null
+++ b/tests/source/configs/reorder_extern_crates/false.rs
@@ -0,0 +1,11 @@
+// rustfmt-reorder_extern_crates: false
+
+extern crate foo;
+extern crate bar;
+extern crate foobar;
+
+#[macro_use]
+extern crate nom;
+extern crate regex;
+#[macro_use]
+extern crate log;
diff --git a/tests/source/configs/reorder_extern_crates/true.rs b/tests/source/configs/reorder_extern_crates/true.rs
new file mode 100644
index 00000000000..bdf00f57cda
--- /dev/null
+++ b/tests/source/configs/reorder_extern_crates/true.rs
@@ -0,0 +1,11 @@
+// rustfmt-reorder_extern_crates: true
+
+extern crate foo;
+extern crate bar;
+extern crate foobar;
+
+#[macro_use]
+extern crate nom;
+extern crate regex;
+#[macro_use]
+extern crate log;
diff --git a/tests/target/configs/reorder_extern_crates/false.rs b/tests/target/configs/reorder_extern_crates/false.rs
new file mode 100644
index 00000000000..6bef132e5c3
--- /dev/null
+++ b/tests/target/configs/reorder_extern_crates/false.rs
@@ -0,0 +1,11 @@
+// rustfmt-reorder_extern_crates: false
+
+extern crate foo;
+extern crate bar;
+extern crate foobar;
+
+#[macro_use]
+extern crate nom;
+extern crate regex;
+#[macro_use]
+extern crate log;
diff --git a/tests/target/configs/reorder_extern_crates/true.rs b/tests/target/configs/reorder_extern_crates/true.rs
new file mode 100644
index 00000000000..86aba38b5d1
--- /dev/null
+++ b/tests/target/configs/reorder_extern_crates/true.rs
@@ -0,0 +1,11 @@
+// rustfmt-reorder_extern_crates: true
+
+extern crate bar;
+extern crate foo;
+extern crate foobar;
+
+#[macro_use]
+extern crate nom;
+extern crate regex;
+#[macro_use]
+extern crate log;

From 3bb0a2a7495011868a52cdbb848f87e59bdc98d8 Mon Sep 17 00:00:00 2001
From: Seiichi Uchida <seuchida@gmail.com>
Date: Sun, 4 Feb 2018 12:08:02 +0900
Subject: [PATCH 2/2] Do not reorder items with '#[macro_use]'

Reordering items with `#[macro_use]` could change the semantic of source code.
There could exist other attributes that requires special treatment.
---
 src/visitor.rs | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/visitor.rs b/src/visitor.rs
index 3157597697d..c28eed561a5 100644
--- a/src/visitor.rs
+++ b/src/visitor.rs
@@ -11,7 +11,7 @@
 use std::cmp;
 
 use syntax::{ast, visit};
-use syntax::attr::HasAttrs;
+use syntax::attr::{self, HasAttrs};
 use syntax::codemap::{self, BytePos, CodeMap, Pos, Span};
 use syntax::parse::ParseSess;
 
@@ -49,11 +49,15 @@ fn is_mod_decl(item: &ast::Item) -> bool {
     }
 }
 
+fn contains_macro_use_attr(attrs: &[ast::Attribute], span: Span) -> bool {
+    attr::contains_name(&filter_inline_attrs(attrs, span), "macro_use")
+}
+
 /// Returns true for `mod foo;` without any inline attributes.
 /// We cannot reorder modules with attributes because doing so can break the code.
 /// e.g. `#[macro_use]`.
 fn is_mod_decl_without_attr(item: &ast::Item) -> bool {
-    is_mod_decl(item) && filter_inline_attrs(&item.attrs, item.span()).is_empty()
+    is_mod_decl(item) && !contains_macro_use_attr(&item.attrs, item.span())
 }
 
 fn is_use_item(item: &ast::Item) -> bool {
@@ -63,6 +67,10 @@ fn is_use_item(item: &ast::Item) -> bool {
     }
 }
 
+fn is_use_item_without_attr(item: &ast::Item) -> bool {
+    is_use_item(item) && !contains_macro_use_attr(&item.attrs, item.span())
+}
+
 fn is_extern_crate(item: &ast::Item) -> bool {
     match item.node {
         ast::ItemKind::ExternCrate(..) => true,
@@ -70,6 +78,10 @@ fn is_extern_crate(item: &ast::Item) -> bool {
     }
 }
 
+fn is_extern_crate_without_attr(item: &ast::Item) -> bool {
+    is_extern_crate(item) && !contains_macro_use_attr(&item.attrs, item.span())
+}
+
 /// Creates a string slice corresponding to the specified span.
 pub struct SnippetProvider<'a> {
     /// A pointer to the content of the file we are formatting.
@@ -676,11 +688,15 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
             // subsequent items that have the same item kind to be reordered within
             // `format_imports`. Otherwise, just format the next item for output.
             {
-                try_reorder_items_with!(reorder_imports, reorder_imports_in_group, is_use_item);
+                try_reorder_items_with!(
+                    reorder_imports,
+                    reorder_imports_in_group,
+                    is_use_item_without_attr
+                );
                 try_reorder_items_with!(
                     reorder_extern_crates,
                     reorder_extern_crates_in_group,
-                    is_extern_crate
+                    is_extern_crate_without_attr
                 );
                 try_reorder_items_with!(reorder_modules, reorder_modules, is_mod_decl_without_attr);
             }