Merge pull request #1627 from topecongiro/issue-1624

Refactor vertical layout of function definition with options

src/items.rs

@@ -1587,7 +1587,10 @@ fn rewrite_fn_base(context: &RewriteContext,
     let generics_str = try_opt!(rewrite_generics(context, generics, shape, generics_span));
     result.push_str(&generics_str);
 
-    let snuggle_angle_bracket = last_line_width(&generics_str) == 1;
+    let snuggle_angle_bracket = generics_str
+        .lines()
+        .last()
+        .map_or(false, |l| l.trim_left().len() == 1);
 
     // Note that the width and indent don't really matter, we'll re-layout the
     // return type later anyway.
@@ -1619,24 +1622,28 @@ fn rewrite_fn_base(context: &RewriteContext,
     // Check if vertical layout was forced.
     if one_line_budget == 0 {
         if snuggle_angle_bracket {
-            result.push_str("(");
-        } else if context.config.fn_args_paren_newline() {
-            result.push('\n');
-            result.push_str(&arg_indent.to_string(context.config));
-            arg_indent = arg_indent + 1; // extra space for `(`
             result.push('(');
-            if context.config.spaces_within_parens() && fd.inputs.len() > 0 {
-                result.push(' ')
-            }
         } else {
-            result.push_str("(\n");
-            result.push_str(&arg_indent.to_string(context.config));
+            if context.config.fn_args_paren_newline() {
+                result.push('\n');
+                result.push_str(&arg_indent.to_string(context.config));
+                if context.config.fn_args_layout() == IndentStyle::Visual {
+                    arg_indent = arg_indent + 1; // extra space for `(`
+                }
+                result.push('(');
+            } else {
+                result.push_str("(");
+                if context.config.fn_args_layout() == IndentStyle::Visual {
+                    result.push('\n');
+                    result.push_str(&arg_indent.to_string(context.config));
+                }
+            }
         }
     } else {
         result.push('(');
-        if context.config.spaces_within_parens() && fd.inputs.len() > 0 {
-            result.push(' ')
-        }
+    }
+    if context.config.spaces_within_parens() && fd.inputs.len() > 0 && result.ends_with('(') {
+        result.push(' ')
     }
 
     if multi_line_ret_str {
@@ -1999,10 +2006,10 @@ fn compute_budgets_for_args(context: &RewriteContext,
 
         if one_line_budget > 0 {
             // 4 = "() {".len()
-            let multi_line_budget = try_opt!(context
-                                                 .config
-                                                 .max_width()
-                                                 .checked_sub(indent.width() + result.len() + 4));
+            let multi_line_overhead = indent.width() + result.len() +
+                                      if newline_brace { 2 } else { 4 };
+            let multi_line_budget =
+                try_opt!(context.config.max_width().checked_sub(multi_line_overhead));
 
             return Some((one_line_budget, multi_line_budget, indent + result.len() + 1));
         }
@@ -2010,14 +2017,10 @@ fn compute_budgets_for_args(context: &RewriteContext,
 
     // Didn't work. we must force vertical layout and put args on a newline.
     let new_indent = indent.block_indent(context.config);
-    let used_space = new_indent.width() + 4; // Account for `(` and `)` and possibly ` {`.
-    let max_space = context.config.max_width();
-    if used_space <= max_space {
-        Some((0, max_space - used_space, new_indent))
-    } else {
-        // Whoops! bankrupt.
-        None
-    }
+    // Account for `)` and possibly ` {`.
+    let used_space = new_indent.width() + if ret_str_len == 0 { 1 } else { 3 };
+    let max_space = try_opt!(context.config.max_width().checked_sub(used_space));
+    Some((0, max_space, new_indent))
 }
 
 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {

tests/target/fn-custom-2.rs

@@ -52,8 +52,7 @@ impl Foo {
         'a: 'bbbbbbbbbbbbbbbbbbbbbbbbbbb,
         TTTTTTTTTTTTT,
         UUUUUUUUUUUUUUUUUUUU: WWWWWWWWWWWWWWWWWWWWWWWW
-    >
-        (
+    >(
         a: Aaaaaaaaaaaaaaa,
     ) {
         bar();

tests/target/fn-custom-3.rs

@@ -54,8 +54,7 @@ impl Foo {
         'a: 'bbbbbbbbbbbbbbbbbbbbbbbbbbb,
         TTTTTTTTTTTTT,
         UUUUUUUUUUUUUUUUUUUU: WWWWWWWWWWWWWWWWWWWWWWWW
-    >
-        (
+    >(
         a: Aaaaaaaaaaaaaaa,
     ) {
         bar();

tests/target/issue-1624.rs

@@ -0,0 +1,9 @@
+// rustfmt-fn_args_layout: Block
+// rustfmt-fn_args_paren_newline: false
+
+// #1624
+pub unsafe fn some_long_function_name(
+    arg1: Type1,
+    arg2: Type2,
+) -> (SomeLongTypeName, AnotherLongTypeName, AnotherLongTypeName) {
+}