Allow {} to remain.

src/expr.rs

@@ -112,6 +112,11 @@ impl Rewrite for ast::Expr {
 
 impl Rewrite for ast::Block {
     fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
+        let user_str = context.codemap.span_to_snippet(self.span).unwrap();
+        if user_str == "{}" && width > 1 {
+            return Some(user_str);
+        }
+
         let mut visitor = FmtVisitor::from_codemap(context.codemap, context.config);
         visitor.block_indent = context.block_indent;
 

tests/source/expr.rs

@@ -91,3 +91,16 @@ fn baz() {
         // Regular unsafe block
     }
 }
+
+// Test some empty blocks.
+fn qux() {
+    {}
+    // FIXME this one could be done better.
+    { /* a block with a comment */ }
+    {
+
+    }
+    {
+        // A block with a comment.
+    }
+}

tests/target/expr.rs

@@ -22,15 +22,13 @@ fn foo() -> bool {
              aaaaa)))))))));
 
     {
-        for _ in 0..10 {
-        }
+        for _ in 0..10 {}
     }
 
     {
         {
             {
-                {
-                }
+                {}
             }
         }
     }
@@ -47,8 +45,7 @@ fn foo() -> bool {
     }
 
     if let Some(x) = (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
-                      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {
-    }
+                      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {}
 
     if let (some_very_large,
             tuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuple) = 1 + 2 + 3 {
@@ -56,8 +53,7 @@ fn foo() -> bool {
 
     if let (some_very_large,
             tuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuple) = 1111 +
-                                                                                         2222 {
-    }
+                                                                                         2222 {}
 
     if let (some_very_large, tuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuple) =
            1 + 2 + 3 {
@@ -121,3 +117,17 @@ fn baz() {
         // Regular unsafe block
     }
 }
+
+// Test some empty blocks.
+fn qux() {
+    {}
+    // FIXME this one could be done better.
+    { /* a block with a comment */
+    }
+    {
+
+    }
+    {
+        // A block with a comment.
+    }
+}

tests/target/loop.rs

@@ -13,8 +13,7 @@ fn main() {
     }
 
     'a: while loooooooooooooooooooooooooooooooooong_variable_name + another_value >
-              some_other_value {
-    }
+              some_other_value {}
 
     while aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa > bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb {
     }