Handle comments in match better (fixes #344)

src/expr.rs

@@ -117,7 +117,7 @@ impl Rewrite for ast::Expr {
                               offset)
             }
             ast::Expr_::ExprMatch(ref cond, ref arms, _) => {
-                rewrite_match(context, cond, arms, width, offset)
+                rewrite_match(context, cond, arms, width, offset, self.span)
             }
             ast::Expr_::ExprPath(ref qself, ref path) => {
                 rewrite_path(context, qself.as_ref(), path, width, offset)
@@ -624,7 +624,8 @@ fn rewrite_match(context: &RewriteContext,
                  cond: &ast::Expr,
                  arms: &[ast::Arm],
                  width: usize,
-                 offset: Indent)
+                 offset: Indent,
+                 span: Span)
                  -> Option<String> {
     if arms.is_empty() {
         return None;
@@ -666,7 +667,8 @@ fn rewrite_match(context: &RewriteContext,
         if !missed_str.is_empty() {
             result.push('\n');
             result.push_str(&arm_indent_str);
-            result.push_str(missed_str);
+            result.push_str(&rewrite_comment(&missed_str, false,
+                                             width, arm_indent, context.config));
         }
         result.push('\n');
         result.push_str(&arm_indent_str);
@@ -682,11 +684,23 @@ fn rewrite_match(context: &RewriteContext,
             result.push_str(&snippet);
         }
     }
-
-    // We'll miss any comments etc. between the last arm and the end of the
-    // match expression, but meh.
+    let last_comment = context.snippet(mk_sp(arm_end_pos(&arms[arms.len() - 1]), span.hi));
+    let last_comment = match last_comment.find_uncommented(",") {
+        Some(n) => &last_comment[n+1..],
+        None => &last_comment[..],
+    };
+    let last_comment = match last_comment.find_uncommented("}") {
+        Some(n) => &last_comment[..n-1],
+        None => &last_comment[..],
+    };
+    let last_comment = last_comment.trim();
 
     result.push('\n');
+    if last_comment.len() > 0 {
+        result.push_str(&arm_indent_str);
+        result.push_str(&rewrite_comment(&last_comment, false, width, arm_indent, context.config));
+        result.push('\n');
+    }
     result.push_str(&(context.block_indent + context.overflow_indent).to_string(context.config));
     result.push('}');
     Some(result)