Support struct-like layouts for fn args

src/config.rs

@@ -90,6 +90,7 @@ pub fn override_value(&mut self, key: &str, val: &str) {
     fn_return_indent: ReturnIndent,
     fn_args_paren_newline: bool,
     fn_args_density: Density,
+    fn_args_layout: StructLitStyle,
     fn_arg_indent: BlockIndentStyle,
     where_density: Density, // Should we at least try to put the where clause on the same line as
                             // the rest of the function decl?
@@ -123,6 +124,7 @@ fn default() -> Config {
             fn_return_indent: ReturnIndent::WithArgs,
             fn_args_paren_newline: true,
             fn_args_density: Density::Tall,
+            fn_args_layout: StructLitStyle::Visual,
             fn_arg_indent: BlockIndentStyle::Visual,
             where_density: Density::Tall,
             where_indent: BlockIndentStyle::Tabbed,
@@ -131,7 +133,7 @@ fn default() -> Config {
             generics_indent: BlockIndentStyle::Visual,
             struct_trailing_comma: SeparatorTactic::Vertical,
             struct_lit_trailing_comma: SeparatorTactic::Vertical,
-            struct_lit_style: StructLitStyle::BlockIndent,
+            struct_lit_style: StructLitStyle::Block,
             enum_trailing_comma: true,
             report_todo: ReportTactic::Always,
             report_fixme: ReportTactic::Never,

src/expr.rs

@@ -940,10 +940,10 @@ enum StructLitField<'a> {
     // Foo { a: Foo } - indent is +3, width is -5.
     let h_budget = try_opt!(width.checked_sub(path_str.len() + 5));
     let (indent, v_budget) = match context.config.struct_lit_style {
-        StructLitStyle::VisualIndent => {
+        StructLitStyle::Visual => {
             (offset + path_str.len() + 3, h_budget)
         }
-        StructLitStyle::BlockIndent => {
+        StructLitStyle::Block => {
             // If we are all on one line, then we'll ignore the indent, and we
             // have a smaller budget.
             let indent = context.block_indent + context.config.tab_spaces;
@@ -1012,7 +1012,7 @@ enum StructLitField<'a> {
     let fields_str = write_list(&items.collect::<Vec<_>>(), &fmt);
 
     match context.config.struct_lit_style {
-        StructLitStyle::BlockIndent if fields_str.contains('\n') => {
+        StructLitStyle::Block if fields_str.contains('\n') => {
             let inner_indent = make_indent(context.block_indent + context.config.tab_spaces);
             let outer_indent = make_indent(context.block_indent);
             Some(format!("{} {{\n{}{}\n{}}}", path_str, inner_indent, fields_str, outer_indent))
@@ -1020,7 +1020,7 @@ enum StructLitField<'a> {
         _ => Some(format!("{} {{ {} }}", path_str, fields_str)),
     }
 
-    // FIXME if context.config.struct_lit_style == VisualIndent, but we run out
+    // FIXME if context.config.struct_lit_style == Visual, but we run out
     // of space, we should fall back to BlockIndent.
 }
 

src/items.rs

@@ -10,7 +10,7 @@
 
 // Formatting top-level items - functions, structs, enums, traits, impls.
 
-use {ReturnIndent, BraceStyle};
+use {ReturnIndent, BraceStyle, StructLitStyle};
 use utils::{format_mutability, format_visibility, make_indent, contains_skip, span_after,
             end_typaram};
 use lists::{write_list, itemize_list, ListItem, ListFormatting, SeparatorTactic, ListTactic};
@@ -225,6 +225,10 @@ fn rewrite_fn_base(&mut self,
                 result.push_str("(\n");
                 result.push_str(&make_indent(arg_indent));
             }
+        } else if self.config.fn_args_layout == StructLitStyle::Block {
+            arg_indent = indent + self.config.tab_spaces;
+            result.push_str("(\n");
+            result.push_str(&make_indent(arg_indent));
         } else {
             result.push('(');
         }
@@ -245,14 +249,20 @@ fn rewrite_fn_base(&mut self,
                                            indent,
                                            arg_indent,
                                            args_span));
+        if self.config.fn_args_layout == StructLitStyle::Block {
+            result.push('\n');
+        }
         result.push(')');
 
         // Return type.
         if !ret_str.is_empty() {
             // If we've already gone multi-line, or the return type would push
             // over the max width, then put the return type on a new line.
-            if result.contains("\n") ||
-               result.len() + indent + ret_str.len() > self.config.max_width {
+            // Unless we are formatting args like a block, in which case there
+            // should always be room for the return type.
+            if (result.contains("\n") ||
+                result.len() + indent + ret_str.len() > self.config.max_width) &&
+               self.config.fn_args_layout != StructLitStyle::Block {
                 let indent = match self.config.fn_return_indent {
                     ReturnIndent::WithWhereClause => indent + 4,
                     // TODO we might want to check that using the arg indent doesn't
@@ -285,8 +295,11 @@ fn rewrite_fn_base(&mut self,
             }
         }
 
-        let where_density = if self.config.where_density == Density::Compressed &&
-                               !result.contains('\n') {
+        let where_density = if (self.config.where_density == Density::Compressed &&
+                                (!result.contains('\n') ||
+                                 self.config.fn_args_layout == StructLitStyle::Block)) ||
+                               (self.config.fn_args_layout == StructLitStyle::Block &&
+                                ret_str.is_empty()) {
             Density::Compressed
         } else {
             Density::Tall

src/lib.rs

@@ -133,13 +133,13 @@ pub enum ReturnIndent {
 pub enum StructLitStyle {
     // First line on the same line as the opening brace, all lines aligned with
     // the first line.
-    VisualIndent,
+    Visual,
     // First line is on a new line and all lines align with block indent.
-    BlockIndent,
+    Block,
     // FIXME Maybe we should also have an option to align types.
 }
 
-impl_enum_decodable!(StructLitStyle, VisualIndent, BlockIndent);
+impl_enum_decodable!(StructLitStyle, Visual, Block);
 
 enum ErrorKind {
     // Line has exceeded character limit

tests/config/small_tabs.toml

@@ -7,6 +7,7 @@ fn_brace_style = "SameLineWhere"
 fn_return_indent = "WithArgs"
 fn_args_paren_newline = true
 fn_args_density = "Tall"
+fn_args_layout = "Visual"
 fn_arg_indent = "Visual"
 where_density = "Tall"
 where_indent = "Tabbed"
@@ -15,7 +16,7 @@ where_pred_indent = "Visual"
 generics_indent = "Visual"
 struct_trailing_comma = "Vertical"
 struct_lit_trailing_comma = "Vertical"
-struct_lit_style = "BlockIndent"
+struct_lit_style = "Block"
 enum_trailing_comma = true
 report_todo = "Always"
 report_fixme = "Never"

tests/source/fn-custom-6.rs

@@ -0,0 +1,36 @@
+// rustfmt-fn_args_layout: Block
+// rustfmt-where_indent: Inherit
+// rustfmt-fn_brace_style: PreferSameLine
+// Test different indents.
+
+fn foo(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb) {
+    foo();
+}
+
+fn bar(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb, c: Cccccccccccccccccc, d: Dddddddddddddddd, e: Eeeeeeeeeeeeeee) {
+    bar();
+}
+
+fn foo(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb) -> String {
+    foo();
+}
+
+fn bar(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb, c: Cccccccccccccccccc, d: Dddddddddddddddd, e: Eeeeeeeeeeeeeee) -> String {
+    bar();
+}
+
+fn foo(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb) where T: UUUUUUUUUUU {
+    foo();
+}
+
+fn bar(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb, c: Cccccccccccccccccc, d: Dddddddddddddddd, e: Eeeeeeeeeeeeeee) where T: UUUUUUUUUUU {
+    bar();
+}
+
+fn foo(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb) -> String where T: UUUUUUUUUUU {
+    foo();
+}
+
+fn bar(a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb, c: Cccccccccccccccccc, d: Dddddddddddddddd, e: Eeeeeeeeeeeeeee) -> String where T: UUUUUUUUUUU {
+    bar();
+}

tests/source/struct_lits_visual.rs

@@ -1,4 +1,4 @@
-// rustfmt-struct_lit_style: VisualIndent
+// rustfmt-struct_lit_style: Visual
 
 // Struct literal expressions.
 

tests/target/fn-custom-6.rs

@@ -0,0 +1,70 @@
+// rustfmt-fn_args_layout: Block
+// rustfmt-where_indent: Inherit
+// rustfmt-fn_brace_style: PreferSameLine
+// Test different indents.
+
+fn foo(
+    a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb
+) {
+    foo();
+}
+
+fn bar(
+    a: Aaaaaaaaaaaaaa,
+    b: Bbbbbbbbbbbbbb,
+    c: Cccccccccccccccccc,
+    d: Dddddddddddddddd,
+    e: Eeeeeeeeeeeeeee
+) {
+    bar();
+}
+
+fn foo(
+    a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb
+) -> String {
+    foo();
+}
+
+fn bar(
+    a: Aaaaaaaaaaaaaa,
+    b: Bbbbbbbbbbbbbb,
+    c: Cccccccccccccccccc,
+    d: Dddddddddddddddd,
+    e: Eeeeeeeeeeeeeee
+) -> String {
+    bar();
+}
+
+fn foo(
+    a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb
+) where T: UUUUUUUUUUU {
+    foo();
+}
+
+fn bar(
+    a: Aaaaaaaaaaaaaa,
+    b: Bbbbbbbbbbbbbb,
+    c: Cccccccccccccccccc,
+    d: Dddddddddddddddd,
+    e: Eeeeeeeeeeeeeee
+) where T: UUUUUUUUUUU {
+    bar();
+}
+
+fn foo(
+    a: Aaaaaaaaaaaaaa, b: Bbbbbbbbbbbbbb
+) -> String
+where T: UUUUUUUUUUU {
+    foo();
+}
+
+fn bar(
+    a: Aaaaaaaaaaaaaa,
+    b: Bbbbbbbbbbbbbb,
+    c: Cccccccccccccccccc,
+    d: Dddddddddddddddd,
+    e: Eeeeeeeeeeeeeee
+) -> String
+where T: UUUUUUUUUUU {
+    bar();
+}

tests/target/struct_lits_visual.rs

@@ -1,4 +1,4 @@
-// rustfmt-struct_lit_style: VisualIndent
+// rustfmt-struct_lit_style: Visual
 
 // Struct literal expressions.