Backport: support closure block indent_style (rust-lang#3867)

Author: calebcartwright

src/closures.rs

@@ -3,7 +3,7 @@ use rustc_span::Span;
 
 use crate::attr::get_attrs_from_stmt;
 use crate::config::lists::*;
-use crate::config::Version;
+use crate::config::{IndentStyle, SeparatorTactic, Version};
 use crate::expr::{block_contains_comment, is_simple_block, is_unsafe_block, rewrite_cond};
 use crate::items::{span_hi_for_param, span_lo_for_param};
 use crate::lists::{definitive_tactic, itemize_list, write_list, ListFormatting, Separator};
@@ -253,9 +253,16 @@ fn rewrite_closure_fn_decl(
         .shrink_left(immovable.len() + is_async.len() + mover.len())?
         .sub_width(4)?;
 
+    let indent_style = context.config.indent_style();
+
     // 1 = |
     let param_offset = nested_shape.indent + 1;
-    let param_shape = nested_shape.offset_left(1)?.visual_indent(0);
+    let param_shape = match indent_style {
+        IndentStyle::Block => {
+            Shape::indented(shape.indent.block_indent(context.config), context.config)
+        }
+        IndentStyle::Visual => nested_shape.offset_left(1)?.visual_indent(0),
+    };
     let ret_str = fn_decl.output.rewrite(context, param_shape)?;
 
     let param_items = itemize_list(
@@ -288,10 +295,31 @@ fn rewrite_closure_fn_decl(
         .tactic(tactic)
         .preserve_newline(true);
     let list_str = write_list(&item_vec, &fmt)?;
-    let mut prefix = format!("{}{}{}|{}|", immovable, is_async, mover, list_str);
+    let one_line_budget = context.budget(param_shape.indent.width());
+    let multi_line_params = match indent_style {
+        IndentStyle::Block => list_str.contains('\n') || list_str.len() > one_line_budget,
+        _ => false,
+    };
+    let put_params_in_block = multi_line_params && !item_vec.is_empty();
+    let param_str = if put_params_in_block {
+        let trailing_comma = match context.config.trailing_comma() {
+            SeparatorTactic::Never => "",
+            _ => ",",
+        };
+        format!(
+            "{}{}{}{}",
+            param_shape.indent.to_string_with_newline(context.config),
+            &list_str,
+            trailing_comma,
+            shape.indent.to_string_with_newline(context.config)
+        )
+    } else {
+        list_str
+    };
+    let mut prefix = format!("{}{}{}|{}|", immovable, is_async, mover, param_str);
 
     if !ret_str.is_empty() {
-        if prefix.contains('\n') {
+        if prefix.contains('\n') && !put_params_in_block {
             prefix.push('\n');
             prefix.push_str(&param_offset.to_string(context.config));
         } else {

tests/source/closure.rs tests/source/closure_block_style.rstests/source/closure.rs renamed to tests/source/closure_block_style.rs

@@ -1,3 +1,4 @@
+// rustfmt-indent_style: Block
 // rustfmt-normalize_comments: true
 // Closures
 
@@ -211,3 +212,15 @@ fn issue2262() {
         slave: None,
     })?;
 }
+
+fn issue_3865() {
+    {
+let write_status = |status: &mut Vec<ansi_term::ANSIString>,
+                        diff: &Diff,
+                        heading: &str,
+                        color: &Style,
+                        show_hints: bool,
+                        hints: &[&str]|-> Option<bool> { Some(true) };}
+                let baz = |foo: bool| -> Option<bool> { Some(true) };
+        let write_status = |status: &mut Vec<ansi_term::ANSIString>,diff: &Diff,heading: &str,color: &Style,| -> Option<bool> { Some(true) };
+}

tests/source/closure_block_style_no_comma.rs

@@ -0,0 +1,17 @@
+// rustfmt-indent_style: Block
+// rustfmt-trailing_comma: Never
+
+fn foo() {
+    {
+let write_status = |status: &mut Vec<ansi_term::ANSIString>,
+                        diff: &Diff,
+                        heading: &str,
+                        color: &Style,
+                        show_hints: bool,
+                        hints: &[&str]|-> Option<bool> { Some(true) };}
+}
+
+fn bar() {
+    let write_status = |status: &mut Vec<ansi_term::ANSIString>,diff: &Diff,heading: &str,color: &Style,| -> Option<bool> { Some(true) };
+    let baz = |foo: bool| -> Option<bool> { Some(true) };
+}

tests/source/closure_visual_style.rs

@@ -0,0 +1,70 @@
+// rustfmt-indent_style: Visual
+// rustfmt-normalize_comments: true
+
+fn foo() {
+    {
+let write_status = |status: &mut Vec<ansi_term::ANSIString>,
+                        diff: &Diff,
+                        heading: &str,
+                        color: &Style,
+                        show_hints: bool,
+                        hints: &[&str]|-> Option<bool> { Some(true) };}
+}
+
+fn bar() {
+    let write_status = |status: &mut Vec<ansi_term::ANSIString>,diff: &Diff,heading: &str,color: &Style,| -> Option<bool> { Some(true) };
+    let baz = |foo: bool| -> Option<bool> { Some(true) };
+}
+
+fn main() {
+    let square = ( |i:  i32 | i  *  i );
+
+        let commented = |// first
+            a, // argument
+                // second
+                b: WithType, // argument
+        // ignored
+    _| {
+        (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb)
+    };
+
+    let commented2 = |/* first */ a /*argument*/, /* second*/ b: WithType /* argument*/, /* ignored */ _ |
+        (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
+
+    let block_body = move   |xxxxxxxxxxxxxxxxxxxxxxxxxxxxx,  ref  yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy| {
+            xxxxxxxxxxxxxxxxxxxxxxxxxxxxx + yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
+        };
+
+    let loooooooooooooong_name = |field| {
+             // format comments.
+             if field.node.attrs.len() > 0 { field.node.attrs[0].span.lo()
+             } else {
+                 field.span.lo()
+             }};
+
+    let unblock_me = |trivial| {
+                         closure()
+                     };
+
+    let empty = |arg|    {};
+
+    let simple = |arg| { /*  comment formatting */ foo(arg) };
+
+    let test = |  | { do_something(); do_something_else(); };
+
+    let arg_test = |big_argument_name, test123| looooooooooooooooooong_function_naaaaaaaaaaaaaaaaame();
+
+    let arg_test = |big_argument_name, test123| {looooooooooooooooooong_function_naaaaaaaaaaaaaaaaame()};
+
+    let simple_closure = move ||   ->  () {};
+
+    let closure = |input: Ty| -> Option<String> {
+        foo()
+    };
+
+    let closure_with_return_type = |aaaaaaaaaaaaaaaaaaaaaaarg1, aaaaaaaaaaaaaaaaaaaaaaarg2| -> Strong { "sup".to_owned() };
+
+    |arg1, arg2, _, _, arg3, arg4| { let temp = arg4 + arg3;
+                                     arg2 * arg1 - temp };
+
+}

tests/target/closure.rs tests/target/closure_block_style.rstests/target/closure.rs renamed to tests/target/closure_block_style.rs

@@ -1,25 +1,28 @@
+// rustfmt-indent_style: Block
 // rustfmt-normalize_comments: true
 // Closures
 
 fn main() {
     let square = (|i: i32| i * i);
 
-    let commented = |// first
-                     a, // argument
-                     // second
-                     b: WithType, // argument
-                     // ignored
-                     _| {
+    let commented = |
+        // first
+        a, // argument
+        // second
+        b: WithType, // argument
+        // ignored
+        _,
+    | {
         (
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
             bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb,
         )
     };
 
-    let block_body = move |xxxxxxxxxxxxxxxxxxxxxxxxxxxxx,
-                           ref yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy| {
-        xxxxxxxxxxxxxxxxxxxxxxxxxxxxx + yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
-    };
+    let block_body = move |
+        xxxxxxxxxxxxxxxxxxxxxxxxxxxxx,
+        ref yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy,
+    | { xxxxxxxxxxxxxxxxxxxxxxxxxxxxx + yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy };
 
     let loooooooooooooong_name = |field| {
         // format comments.
@@ -248,3 +251,23 @@ fn issue2262() {
             slave: None,
         })?;
 }
+
+fn issue_3865() {
+    {
+        let write_status = |
+            status: &mut Vec<ansi_term::ANSIString>,
+            diff: &Diff,
+            heading: &str,
+            color: &Style,
+            show_hints: bool,
+            hints: &[&str],
+        | -> Option<bool> { Some(true) };
+    }
+    let baz = |foo: bool| -> Option<bool> { Some(true) };
+    let write_status = |
+        status: &mut Vec<ansi_term::ANSIString>,
+        diff: &Diff,
+        heading: &str,
+        color: &Style,
+    | -> Option<bool> { Some(true) };
+}

tests/target/closure_block_style_no_comma.rs

@@ -0,0 +1,25 @@
+// rustfmt-indent_style: Block
+// rustfmt-trailing_comma: Never
+
+fn foo() {
+    {
+        let write_status = |
+            status: &mut Vec<ansi_term::ANSIString>,
+            diff: &Diff,
+            heading: &str,
+            color: &Style,
+            show_hints: bool,
+            hints: &[&str]
+        | -> Option<bool> { Some(true) };
+    }
+}
+
+fn bar() {
+    let write_status = |
+        status: &mut Vec<ansi_term::ANSIString>,
+        diff: &Diff,
+        heading: &str,
+        color: &Style
+    | -> Option<bool> { Some(true) };
+    let baz = |foo: bool| -> Option<bool> { Some(true) };
+}

tests/target/closure_visual_style.rs

@@ -0,0 +1,90 @@
+// rustfmt-indent_style: Visual
+// rustfmt-normalize_comments: true
+
+fn foo() {
+    {
+        let write_status = |status: &mut Vec<ansi_term::ANSIString>,
+                            diff: &Diff,
+                            heading: &str,
+                            color: &Style,
+                            show_hints: bool,
+                            hints: &[&str]|
+         -> Option<bool> { Some(true) };
+    }
+}
+
+fn bar() {
+    let write_status = |status: &mut Vec<ansi_term::ANSIString>,
+                        diff: &Diff,
+                        heading: &str,
+                        color: &Style|
+     -> Option<bool> { Some(true) };
+    let baz = |foo: bool| -> Option<bool> { Some(true) };
+}
+
+fn main() {
+    let square = (|i: i32| i * i);
+
+    let commented = |// first
+                     a, // argument
+                     // second
+                     b: WithType, // argument
+                     // ignored
+                     _| {
+        (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb)
+    };
+
+    let commented2 =
+        |// first
+         a, // argument
+         // second
+         b: WithType, // argument
+         // ignored
+         _| (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb);
+
+    let block_body = move |xxxxxxxxxxxxxxxxxxxxxxxxxxxxx,
+                           ref yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy| {
+        xxxxxxxxxxxxxxxxxxxxxxxxxxxxx + yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
+    };
+
+    let loooooooooooooong_name = |field| {
+        // format comments.
+        if field.node.attrs.len() > 0 {
+            field.node.attrs[0].span.lo()
+        } else {
+            field.span.lo()
+        }
+    };
+
+    let unblock_me = |trivial| closure();
+
+    let empty = |arg| {};
+
+    let simple = |arg| {
+        // comment formatting
+        foo(arg)
+    };
+
+    let test = || {
+        do_something();
+        do_something_else();
+    };
+
+    let arg_test =
+        |big_argument_name, test123| looooooooooooooooooong_function_naaaaaaaaaaaaaaaaame();
+
+    let arg_test =
+        |big_argument_name, test123| looooooooooooooooooong_function_naaaaaaaaaaaaaaaaame();
+
+    let simple_closure = move || -> () {};
+
+    let closure = |input: Ty| -> Option<String> { foo() };
+
+    let closure_with_return_type =
+        |aaaaaaaaaaaaaaaaaaaaaaarg1, aaaaaaaaaaaaaaaaaaaaaaarg2| -> Strong { "sup".to_owned() };
+
+    |arg1, arg2, _, _, arg3, arg4| {
+        let temp = arg4 + arg3;
+        arg2 * arg1 - temp
+    };
+}

tests/target/fn-param-attributes.rs

@@ -28,11 +28,13 @@ impl MutStruct {
 }
 
 fn main() {
-    let c = |#[allow(C)] a: u32,
-             #[cfg(something)] b: i32,
-             #[cfg_attr(something, cfg(nothing))]
-             #[deny(C)]
-             c: i32| {};
+    let c = |
+        #[allow(C)] a: u32,
+        #[cfg(something)] b: i32,
+        #[cfg_attr(something, cfg(nothing))]
+        #[deny(C)]
+        c: i32,
+    | {};
     let _ = c(1, 2);
 }
 

tests/target/mulit-file.rs tests/target/multi-file.rstests/target/mulit-file.rs renamed to tests/target/multi-file.rs

@@ -2,9 +2,9 @@
 // crash.
 
 #[cfg(all(foo))]
-#[path = "closure.rs"]
+#[path = "closure_block_style.rs"]
 pub mod imp;
 
 #[cfg(all(bar))]
-#[path = "closure.rs"]
+#[path = "closure_block_style.rs"]
 pub mod imp;