Omit newline for empty macro branches

src/macros.rs

@@ -400,7 +400,7 @@ pub fn rewrite_macro_def(
 
         if has_block_body {
             result += new_body.trim();
-        } else {
+        } else if !new_body.is_empty() {
             result += "\n";
             result += &new_body;
             result += &mac_indent_str;

tests/target/macro_not_expr.rs

@@ -1,6 +1,5 @@
 macro_rules! test {
-    ($($t: tt)*) => {
-    };
+    ($($t: tt)*) => {};
 }
 
 fn main() {

tests/target/macro_rules.rs

@@ -4,8 +4,7 @@ macro_rules! m {
         $func(x)
     }};
 
-    () => {
-    };
+    () => {};
 
     ($item: ident) => {
         mod macro_item {

tests/target/macros.rs

@@ -141,8 +141,7 @@ fn issue_1555() {
 
 fn issue1178() {
     macro_rules! foo {
-        (#[$attr: meta] $name: ident) => {
-        };
+        (#[$attr: meta] $name: ident) => {};
     }
 
     foo!(
@@ -890,8 +889,7 @@ fn macro_in_pattern_position() {
     };
 }
 
-macro foo() {
-}
+macro foo() {}
 
 pub macro bar($x: ident + $y: expr;) {
     fn foo($x: Foo) {