From 0d4fb2403cf30e452f39f78d5a463738a35a52bb Mon Sep 17 00:00:00 2001
From: topecongiro <seuchida@gmail.com>
Date: Sun, 14 Apr 2019 20:12:58 +0900
Subject: [PATCH 1/3] Add a test for #3509

---
 tests/source/attrib.rs | 15 +++++++++++++++
 tests/target/attrib.rs | 18 ++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/tests/source/attrib.rs b/tests/source/attrib.rs
index f92c9cd31e23..7f17bdad0ac2 100644
--- a/tests/source/attrib.rs
+++ b/tests/source/attrib.rs
@@ -217,3 +217,18 @@ fn stmt_expr_attributes() {
     #[must_use]
    foo = false ;
 }
+
+// #3509
+fn issue3509() {
+    match MyEnum {
+        MyEnum::Option1 if cfg!(target_os = "windows") =>
+            #[cfg(target_os = "windows")]{
+                1
+            }
+    }
+    match MyEnum {
+        MyEnum::Option1 if cfg!(target_os = "windows") =>
+            #[cfg(target_os = "windows")]
+                1,
+    }
+}
diff --git a/tests/target/attrib.rs b/tests/target/attrib.rs
index b5a6c3491de1..edde124a6c08 100644
--- a/tests/target/attrib.rs
+++ b/tests/target/attrib.rs
@@ -252,3 +252,21 @@ fn stmt_expr_attributes() {
     #[must_use]
     foo = false;
 }
+
+// #3509
+fn issue3509() {
+    match MyEnum {
+        MyEnum::Option1 if cfg!(target_os = "windows") =>
+        #[cfg(target_os = "windows")]
+        {
+            1
+        }
+    }
+    match MyEnum {
+        MyEnum::Option1 if cfg!(target_os = "windows") =>
+        {
+            #[cfg(target_os = "windows")]
+            1
+        }
+    }
+}

From 3d80678e248ec880b5ee363f123b298189c7724b Mon Sep 17 00:00:00 2001
From: topecongiro <seuchida@gmail.com>
Date: Sun, 14 Apr 2019 20:13:07 +0900
Subject: [PATCH 2/3] Do not include body's attributes in `arrow_span`

---
 src/matches.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/matches.rs b/src/matches.rs
index c3102f121234..84fe1bdafe80 100644
--- a/src/matches.rs
+++ b/src/matches.rs
@@ -263,7 +263,7 @@ fn rewrite_match_arm(
         false,
     )?;
 
-    let arrow_span = mk_sp(arm.pats.last().unwrap().span.hi(), arm.body.span.lo());
+    let arrow_span = mk_sp(arm.pats.last().unwrap().span.hi(), arm.body.span().lo());
     rewrite_match_body(
         context,
         &arm.body,

From b57e0e22795a881b670defa205908964fb0a8040 Mon Sep 17 00:00:00 2001
From: topecongiro <seuchida@gmail.com>
Date: Sun, 14 Apr 2019 20:13:54 +0900
Subject: [PATCH 3/3] Disallow putting a body with attributes on the same line

---
 src/matches.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/matches.rs b/src/matches.rs
index 84fe1bdafe80..c09949cf2e86 100644
--- a/src/matches.rs
+++ b/src/matches.rs
@@ -364,7 +364,8 @@ fn rewrite_match_body(
         shape.indent
     };
 
-    let forbid_same_line = has_guard && pats_str.contains('\n') && !is_empty_block;
+    let forbid_same_line =
+        (has_guard && pats_str.contains('\n') && !is_empty_block) || !body.attrs.is_empty();
 
     // Look for comments between `=>` and the start of the body.
     let arrow_comment = {