diff --git a/src/functions.rs b/src/functions.rs
index 32ad65befe7..777120f5b97 100644
--- a/src/functions.rs
+++ b/src/functions.rs
@@ -68,6 +68,9 @@ impl<'a> FmtVisitor<'a> {
         let (one_line_budget, multi_line_budget, arg_indent) =
             self.compute_budgets_for_args(&mut result, indent, ret_str.len(), newline_brace);
 
+        debug!("rewrite_fn: one_line_budget: {}, multi_line_budget: {}, arg_indent: {}",
+               one_line_budget, multi_line_budget, arg_indent);
+
         result.push('(');
         result.push_str(&self.rewrite_args(&fd.inputs,
                                            explicit_self,
@@ -252,8 +255,8 @@ impl<'a> FmtVisitor<'a> {
         // Try keeping everything on the same line
         if !result.contains("\n") {
             // 3 = `() `, space is before ret_string
-            let mut used_space = indent + result.len() + 3 + ret_str_len;
-            if newline_brace {
+            let mut used_space = indent + result.len() + ret_str_len + 3;
+            if !newline_brace {
                 used_space += 2;
             }
             let one_line_budget = if used_space > MAX_WIDTH {
@@ -262,11 +265,13 @@ impl<'a> FmtVisitor<'a> {
                 MAX_WIDTH - used_space
             };
 
+            // 2 = `()`
             let used_space = indent + result.len() + 2;
             let max_space = IDEAL_WIDTH + LEEWAY;
+            debug!("compute_budgets_for_args: used_space: {}, max_space: {}",
+                   used_space, max_space);
             if used_space < max_space {
                 budgets = Some((one_line_budget,
-                                // 2 = `()`
                                 max_space - used_space,
                                 indent + result.len() + 1));
             }
diff --git a/src/lists.rs b/src/lists.rs
index 5a892e5713b..d5f058a301b 100644
--- a/src/lists.rs
+++ b/src/lists.rs
@@ -63,6 +63,8 @@ pub fn write_list<'b>(items: &[(String, String)], formatting: &ListFormatting<'b
 
     // Check if we need to fallback from horizontal listing, if possible.
     if tactic == ListTactic::HorizontalVertical {
+        debug!("write_list: total_width: {}, total_sep_len: {}, h_width: {}",
+               total_width, total_sep_len, formatting.h_width);
         if total_width + total_sep_len > formatting.h_width {
             tactic = ListTactic::Vertical;
         } else {
diff --git a/src/mod.rs b/src/mod.rs
index 71ce9120fe1..c5f5150b3bb 100644
--- a/src/mod.rs
+++ b/src/mod.rs
@@ -157,6 +157,7 @@ fn fmt_lines(changes: &mut ChangeSet) {
         }
 
         if newline_count > 1 {
+            debug!("track truncate: {} {} {}", f, text.len, newline_count);
             truncate_todo.push((f, text.len - newline_count + 1))
         }
 
diff --git a/tests/idem/long-fn-1.rs b/tests/idem/long-fn-1.rs
new file mode 100644
index 00000000000..0e299aaecc1
--- /dev/null
+++ b/tests/idem/long-fn-1.rs
@@ -0,0 +1,13 @@
+// Tests that a function which is almost short enough, but not quite, gets
+// formatted correctly.
+
+impl Foo {
+    fn some_input(&mut self,
+                  input: Input,
+                  input_path: Option<PathBuf>)
+                  -> (Input, Option<PathBuf>) {
+    }
+
+    fn some_inpu(&mut self, input: Input, input_path: Option<PathBuf>) -> (Input, Option<PathBuf>) {
+    }
+}