From fc7f6e11fe5292e628d44a5eb49c6c6fd96039a8 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 17 Apr 2024 17:37:46 -0400
Subject: [PATCH 1/6] Implement preserve mode for trailing-semicolon

---
 Configurations.md                             | 20 ++++++--
 src/config/mod.rs                             |  4 +-
 src/config/options.rs                         |  7 +++
 src/utils.rs                                  | 18 +++++--
 .../trailing_semicolon/{true.rs => always.rs} |  2 +-
 .../trailing_semicolon/{false.rs => never.rs} |  2 +-
 .../configs/trailing_semicolon/preserve.rs    | 49 +++++++++++++++++++
 .../issue-5797/retain_trailing_semicolon.rs   |  2 +-
 8 files changed, 91 insertions(+), 13 deletions(-)
 rename tests/target/configs/trailing_semicolon/{true.rs => always.rs} (89%)
 rename tests/target/configs/trailing_semicolon/{false.rs => never.rs} (89%)
 create mode 100644 tests/target/configs/trailing_semicolon/preserve.rs

diff --git a/Configurations.md b/Configurations.md
index 2d01fb3bb3b..6d858fb5da5 100644
--- a/Configurations.md
+++ b/Configurations.md
@@ -2780,20 +2780,32 @@ See also: [`match_block_trailing_comma`](#match_block_trailing_comma).
 
 Add trailing semicolon after break, continue and return
 
-- **Default value**: `true`
-- **Possible values**: `true`, `false`
+- **Default value**: `preserve`
+- **Possible values**: `always`, `never`, `preserve`
 - **Stable**: No (tracking issue: [#3378](https://github.com/rust-lang/rustfmt/issues/3378))
 
-#### `true` (default):
+#### `always` (default):
 ```rust
 fn foo() -> usize {
     return 0;
 }
 ```
 
-#### `false`:
+#### `never`:
+```rust
+fn foo() -> usize {
+    return 0
+}
+```
+
+
+#### `preserve`:
 ```rust
 fn foo() -> usize {
+    return 0;
+}
+
+fn bar() -> usize {
     return 0
 }
 ```
diff --git a/src/config/mod.rs b/src/config/mod.rs
index 9484b2e5829..04f4f212fc3 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -135,7 +135,7 @@ create_config! {
     brace_style: BraceStyle, BraceStyle::SameLineWhere, false, "Brace style for items";
     control_brace_style: ControlBraceStyle, ControlBraceStyle::AlwaysSameLine, false,
         "Brace style for control flow constructs";
-    trailing_semicolon: bool, true, false,
+    trailing_semicolon: TrailingSemicolon, TrailingSemicolon::Preserve, false,
         "Add trailing semicolon after break, continue and return";
     trailing_comma: SeparatorTactic, SeparatorTactic::Vertical, false,
         "How to handle trailing commas for lists";
@@ -673,7 +673,7 @@ force_multiline_blocks = false
 fn_params_layout = "Tall"
 brace_style = "SameLineWhere"
 control_brace_style = "AlwaysSameLine"
-trailing_semicolon = true
+trailing_semicolon = preserve
 trailing_comma = "Vertical"
 match_block_trailing_comma = false
 blank_lines_upper_bound = 1
diff --git a/src/config/options.rs b/src/config/options.rs
index 3c5c713a33a..04c78ffc39a 100644
--- a/src/config/options.rs
+++ b/src/config/options.rs
@@ -49,6 +49,13 @@ pub enum ControlBraceStyle {
     AlwaysNextLine,
 }
 
+#[config_type]
+pub enum TrailingSemicolon {
+    Always,
+    Never,
+    Preserve,
+}
+
 #[config_type]
 /// How to indent.
 pub enum IndentStyle {
diff --git a/src/utils.rs b/src/utils.rs
index 642b6603b1e..26d867a1761 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -10,7 +10,7 @@ use rustc_span::{sym, symbol, BytePos, LocalExpnId, Span, Symbol, SyntaxContext}
 use unicode_width::UnicodeWidthStr;
 
 use crate::comment::{filter_normal_code, CharClasses, FullCodeCharKind, LineClasses};
-use crate::config::{Config, Version};
+use crate::config::{Config, TrailingSemicolon, Version};
 use crate::rewrite::RewriteContext;
 use crate::shape::{Indent, Shape};
 
@@ -273,7 +273,7 @@ pub(crate) fn contains_skip(attrs: &[Attribute]) -> bool {
 #[inline]
 pub(crate) fn semicolon_for_expr(context: &RewriteContext<'_>, expr: &ast::Expr) -> bool {
     // Never try to insert semicolons on expressions when we're inside
-    // a macro definition - this can prevent the macro from compiling
+    // a macro definition - this  can prevent the macro from compiling
     // when used in expression position
     if context.is_macro_def {
         return false;
@@ -281,7 +281,10 @@ pub(crate) fn semicolon_for_expr(context: &RewriteContext<'_>, expr: &ast::Expr)
 
     match expr.kind {
         ast::ExprKind::Ret(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Break(..) => {
-            context.config.trailing_semicolon()
+            match context.config.trailing_semicolon() {
+                TrailingSemicolon::Always => true,
+                TrailingSemicolon::Never | TrailingSemicolon::Preserve => false,
+            }
         }
         _ => false,
     }
@@ -301,7 +304,14 @@ pub(crate) fn semicolon_for_stmt(
             ast::ExprKind::Break(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Ret(..) => {
                 // The only time we can skip the semi-colon is if the config option is set to false
                 // **and** this is the last expr (even though any following exprs are unreachable)
-                context.config.trailing_semicolon() || !is_last_expr
+                if !is_last_expr {
+                    true
+                } else {
+                    match context.config.trailing_semicolon() {
+                        TrailingSemicolon::Always | TrailingSemicolon::Preserve => true,
+                        TrailingSemicolon::Never => false,
+                    }
+                }
             }
             _ => true,
         },
diff --git a/tests/target/configs/trailing_semicolon/true.rs b/tests/target/configs/trailing_semicolon/always.rs
similarity index 89%
rename from tests/target/configs/trailing_semicolon/true.rs
rename to tests/target/configs/trailing_semicolon/always.rs
index 61b6843d677..764ef8792bc 100644
--- a/tests/target/configs/trailing_semicolon/true.rs
+++ b/tests/target/configs/trailing_semicolon/always.rs
@@ -1,4 +1,4 @@
-// rustfmt-trailing_semicolon: true
+// rustfmt-trailing_semicolon: always
 
 #![feature(loop_break_value)]
 
diff --git a/tests/target/configs/trailing_semicolon/false.rs b/tests/target/configs/trailing_semicolon/never.rs
similarity index 89%
rename from tests/target/configs/trailing_semicolon/false.rs
rename to tests/target/configs/trailing_semicolon/never.rs
index 9fa746e9c0f..f4fce216f1a 100644
--- a/tests/target/configs/trailing_semicolon/false.rs
+++ b/tests/target/configs/trailing_semicolon/never.rs
@@ -1,4 +1,4 @@
-// rustfmt-trailing_semicolon: false
+// rustfmt-trailing_semicolon: never
 
 #![feature(loop_break_value)]
 
diff --git a/tests/target/configs/trailing_semicolon/preserve.rs b/tests/target/configs/trailing_semicolon/preserve.rs
new file mode 100644
index 00000000000..7804f230a81
--- /dev/null
+++ b/tests/target/configs/trailing_semicolon/preserve.rs
@@ -0,0 +1,49 @@
+// rustfmt-trailing_semicolon: never
+
+#![feature(loop_break_value)]
+
+fn main() {
+    'a: loop {
+        break 'a
+    }
+
+    let mut done = false;
+    'b: while !done {
+        done = true;
+        continue 'b
+    }
+
+    let x = loop {
+        break 5
+    };
+
+    let x = 'c: loop {
+        break 'c 5
+    };
+
+    'a: loop {
+        break 'a;
+    }
+
+    let mut done = false;
+    'b: while !done {
+        done = true;
+        continue 'b;
+    }
+
+    let x = loop {
+        break 5;
+    };
+
+    let x = 'c: loop {
+        break 'c 5;
+    };
+}
+
+fn foo() -> usize {
+    return 0
+}
+
+fn bar() -> usize {
+    return 0;
+}
diff --git a/tests/target/issue-5797/retain_trailing_semicolon.rs b/tests/target/issue-5797/retain_trailing_semicolon.rs
index 851073971f6..6eaf426cf5f 100644
--- a/tests/target/issue-5797/retain_trailing_semicolon.rs
+++ b/tests/target/issue-5797/retain_trailing_semicolon.rs
@@ -1,4 +1,4 @@
-// rustfmt-trailing_semicolon: false
+// rustfmt-trailing_semicolon: never
 
 fn foo() {}
 fn main() {

From 10e6db2f48dcd3bdff73fedebcb796426632d66c Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 17 Apr 2024 17:56:13 -0400
Subject: [PATCH 2/6] Bless tests

---
 .../single_line_let_else_max_width/100.rs     | 14 ++++----
 .../single_line_let_else_max_width/50.rs      | 16 +++++-----
 .../single_line_let_else_max_width/zero.rs    | 20 ++++++------
 .../configs/use_small_heuristics/default.rs   |  2 +-
 .../configs/use_small_heuristics/off.rs       |  6 ++--
 tests/target/expr.rs                          | 10 ++----
 tests/target/issue-3213/version_two.rs        |  2 +-
 tests/target/let_else.rs                      | 32 +++++++++----------
 8 files changed, 49 insertions(+), 53 deletions(-)

diff --git a/tests/target/configs/single_line_let_else_max_width/100.rs b/tests/target/configs/single_line_let_else_max_width/100.rs
index 0409124a5b0..c262a5a0e8d 100644
--- a/tests/target/configs/single_line_let_else_max_width/100.rs
+++ b/tests/target/configs/single_line_let_else_max_width/100.rs
@@ -9,12 +9,12 @@ fn main() {
 
     let Some(c) = opt else {
         // a comment should always force the block to be multi-lined
-        return;
+        return
     };
 
     let Some(c) = opt else {
         /* a comment should always force the block to be multi-lined */
-        return;
+        return
     };
 
     let Some(d) = some_very_very_very_very_long_name else { return };
@@ -26,11 +26,11 @@ fn main() {
         range: _,
     }) = slice.as_ref()
     else {
-        return;
+        return
     };
 
     let Some((base_place, current)) = self.lower_expr_as_place(current, *base, true)? else {
-        return Ok(None);
+        return Ok(None)
     };
 
     let Some(doc_attr) = variant
@@ -38,11 +38,11 @@ fn main() {
         .iter()
         .find(|attr| attr.path().is_ident("doc"))
     else {
-        return Err(Error::new(variant.span(), r#"expected a doc comment"#));
+        return Err(Error::new(variant.span(), r#"expected a doc comment"#))
     };
 
     let Some((base_place, current)) = self.lower_expr_as_place(current, *base, true) else {
-        return Ok(None);
+        return Ok(None)
     };
 
     let Stmt::Expr(
@@ -55,6 +55,6 @@ fn main() {
         return Err(Error::new(
             last_stmt.span(),
             "expected last expression to be `Some(match (..) { .. })`",
-        ));
+        ))
     };
 }
diff --git a/tests/target/configs/single_line_let_else_max_width/50.rs b/tests/target/configs/single_line_let_else_max_width/50.rs
index 6afc2b6f2b0..20c41f7482c 100644
--- a/tests/target/configs/single_line_let_else_max_width/50.rs
+++ b/tests/target/configs/single_line_let_else_max_width/50.rs
@@ -9,16 +9,16 @@ fn main() {
 
     let Some(c) = opt else {
         // a comment should always force the block to be multi-lined
-        return;
+        return
     };
 
     let Some(c) = opt else {
         /* a comment should always force the block to be multi-lined */
-        return;
+        return
     };
 
     let Some(d) = some_very_very_very_very_long_name else {
-        return;
+        return
     };
 
     let Expr::Slice(ast::ExprSlice {
@@ -28,11 +28,11 @@ fn main() {
         range: _,
     }) = slice.as_ref()
     else {
-        return;
+        return
     };
 
     let Some((base_place, current)) = self.lower_expr_as_place(current, *base, true)? else {
-        return Ok(None);
+        return Ok(None)
     };
 
     let Some(doc_attr) = variant
@@ -40,11 +40,11 @@ fn main() {
         .iter()
         .find(|attr| attr.path().is_ident("doc"))
     else {
-        return Err(Error::new(variant.span(), r#"expected a doc comment"#));
+        return Err(Error::new(variant.span(), r#"expected a doc comment"#))
     };
 
     let Some((base_place, current)) = self.lower_expr_as_place(current, *base, true) else {
-        return Ok(None);
+        return Ok(None)
     };
 
     let Stmt::Expr(
@@ -57,6 +57,6 @@ fn main() {
         return Err(Error::new(
             last_stmt.span(),
             "expected last expression to be `Some(match (..) { .. })`",
-        ));
+        ))
     };
 }
diff --git a/tests/target/configs/single_line_let_else_max_width/zero.rs b/tests/target/configs/single_line_let_else_max_width/zero.rs
index b5fd0b9edaf..0a46d009f46 100644
--- a/tests/target/configs/single_line_let_else_max_width/zero.rs
+++ b/tests/target/configs/single_line_let_else_max_width/zero.rs
@@ -4,25 +4,25 @@ fn main() {
     let Some(a) = opt else {};
 
     let Some(b) = opt else {
-        return;
+        return
     };
 
     let Some(c) = opt else {
-        return;
+        return
     };
 
     let Some(c) = opt else {
         // a comment should always force the block to be multi-lined
-        return;
+        return
     };
 
     let Some(c) = opt else {
         /* a comment should always force the block to be multi-lined */
-        return;
+        return
     };
 
     let Some(d) = some_very_very_very_very_long_name else {
-        return;
+        return
     };
 
     let Expr::Slice(ast::ExprSlice {
@@ -32,11 +32,11 @@ fn main() {
         range: _,
     }) = slice.as_ref()
     else {
-        return;
+        return
     };
 
     let Some((base_place, current)) = self.lower_expr_as_place(current, *base, true)? else {
-        return Ok(None);
+        return Ok(None)
     };
 
     let Some(doc_attr) = variant
@@ -44,11 +44,11 @@ fn main() {
         .iter()
         .find(|attr| attr.path().is_ident("doc"))
     else {
-        return Err(Error::new(variant.span(), r#"expected a doc comment"#));
+        return Err(Error::new(variant.span(), r#"expected a doc comment"#))
     };
 
     let Some((base_place, current)) = self.lower_expr_as_place(current, *base, true) else {
-        return Ok(None);
+        return Ok(None)
     };
 
     let Stmt::Expr(
@@ -61,6 +61,6 @@ fn main() {
         return Err(Error::new(
             last_stmt.span(),
             "expected last expression to be `Some(match (..) { .. })`",
-        ));
+        ))
     };
 }
diff --git a/tests/target/configs/use_small_heuristics/default.rs b/tests/target/configs/use_small_heuristics/default.rs
index ad40739233e..829d5f6a24b 100644
--- a/tests/target/configs/use_small_heuristics/default.rs
+++ b/tests/target/configs/use_small_heuristics/default.rs
@@ -33,6 +33,6 @@ fn format_let_else() {
     let Some(c) = opt else { return };
 
     let Some(d) = some_very_very_very_very_long_name else {
-        return;
+        return
     };
 }
diff --git a/tests/target/configs/use_small_heuristics/off.rs b/tests/target/configs/use_small_heuristics/off.rs
index b0b4e4ee49f..90e1e1c976d 100644
--- a/tests/target/configs/use_small_heuristics/off.rs
+++ b/tests/target/configs/use_small_heuristics/off.rs
@@ -28,14 +28,14 @@ fn format_let_else() {
     let Some(a) = opt else {};
 
     let Some(b) = opt else {
-        return;
+        return
     };
 
     let Some(c) = opt else {
-        return;
+        return
     };
 
     let Some(d) = some_very_very_very_very_long_name else {
-        return;
+        return
     };
 }
diff --git a/tests/target/expr.rs b/tests/target/expr.rs
index 187a1dc976a..8ce3546f72a 100644
--- a/tests/target/expr.rs
+++ b/tests/target/expr.rs
@@ -125,7 +125,7 @@ fn bar() {
 
     loop {
         if true {
-            break;
+            break
         }
     }
 
@@ -536,18 +536,14 @@ fn issue3226() {
     {
         {
             {
-                return Err(
-                    ErrorKind::ManagementInterfaceError("Server exited unexpectedly").into(),
-                );
+                return Err(ErrorKind::ManagementInterfaceError("Server exited unexpectedly").into())
             }
         }
     }
     {
         {
             {
-                break Err(
-                    ErrorKind::ManagementInterfaceError("Server exited unexpectedlyy").into(),
-                );
+                break Err(ErrorKind::ManagementInterfaceError("Server exited unexpectedlyy").into())
             }
         }
     }
diff --git a/tests/target/issue-3213/version_two.rs b/tests/target/issue-3213/version_two.rs
index de93d04ba95..ee5b2ec56d8 100644
--- a/tests/target/issue-3213/version_two.rs
+++ b/tests/target/issue-3213/version_two.rs
@@ -3,7 +3,7 @@
 fn foo() {
     match 0 {
         0 => {
-            return AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA;
+            return AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
         }
         1 => {
             AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
diff --git a/tests/target/let_else.rs b/tests/target/let_else.rs
index 528d2929734..c222498bb4a 100644
--- a/tests/target/let_else.rs
+++ b/tests/target/let_else.rs
@@ -21,7 +21,7 @@ fn main() {
 
     let Some(x) = opt else {
         let y = 1;
-        return y;
+        return y
     };
 
     let Some(x) = y.foo(
@@ -54,13 +54,13 @@ fn with_comments_around_else_keyword() {
     let Some(x) = opt
     /* pre else keyword block-comment */
     else {
-        return;
+        return
     };
 
     let Some(x) = opt else
     /* post else keyword block-comment */
     {
-        return;
+        return
     };
 
     let Some(x) = opt
@@ -68,19 +68,19 @@ fn with_comments_around_else_keyword() {
     else
     /* post else keyword block-comment */
     {
-        return;
+        return
     };
 
     let Some(x) = opt
     // pre else keyword line-comment
     else {
-        return;
+        return
     };
 
     let Some(x) = opt else
     // post else keyword line-comment
     {
-        return;
+        return
     };
 
     let Some(x) = opt
@@ -88,7 +88,7 @@ fn with_comments_around_else_keyword() {
     else
     // post else keyword line-comment
     {
-        return;
+        return
     };
 }
 
@@ -106,7 +106,7 @@ fn unbreakable_initializer_expr_pre_formatting_let_else_length_near_max_width()
     // and the else block is formatted over multiple lines because we can't fit the
     // else block on the same line as the initializer expr.
     let Some(x) = some_really_really_really_really_really_really_really_long_name___B else {
-        return;
+        return
     };
 
     // Pre Formatting:
@@ -126,7 +126,7 @@ fn unbreakable_initializer_expr_pre_formatting_let_else_length_near_max_width()
     // and the else block is formatted over multiple lines because we can't fit the
     // else block on the same line as the initializer expr.
     let Some(x) = some_really_really_really_really_really_really_really_long_name__D else {
-        return;
+        return
     };
 }
 
@@ -138,7 +138,7 @@ fn unbreakable_initializer_expr_pre_formatting_length_up_to_opening_brace_near_m
     // and the else block is formatted over multiple lines because we can't fit the
     // else block on the same line as the initializer expr.
     let Some(x) = some_really_really_really_really_really_really_really_really_long_name___E else {
-        return;
+        return
     };
 
     // Pre Formatting:
@@ -148,7 +148,7 @@ fn unbreakable_initializer_expr_pre_formatting_length_up_to_opening_brace_near_m
     // They are formatted on the next line.
     let Some(x) = some_really_really_really_really_really_really_really_really_long_name_____F
     else {
-        return;
+        return
     };
 }
 
@@ -160,7 +160,7 @@ fn unbreakable_initializer_expr_pre_formatting_length_through_initializer_expr_n
     // They are formatted on the next line.
     let Some(x) = some_really_really_really_really_really_really_really_really_really_long_name___G
     else {
-        return;
+        return
     };
 
     // Pre Formatting:
@@ -171,7 +171,7 @@ fn unbreakable_initializer_expr_pre_formatting_length_through_initializer_expr_n
     let Some(x) =
         some_really_really_really_really_really_really_really_really_really_long_name____H
     else {
-        return;
+        return
     };
 
     // Pre Formatting:
@@ -186,7 +186,7 @@ fn unbreakable_initializer_expr_pre_formatting_length_through_initializer_expr_n
     let Some(x) =
         some_really_really_really_really_really_really_really_really_really_really_long_name______I
     else {
-        return;
+        return
     };
 
     // Pre Formatting:
@@ -240,7 +240,7 @@ fn with_trailing_try_operator() {
         &ranking_rule_universes[cur_ranking_rule_index],
     )?
     else {
-        return;
+        return
     };
 
     // Maybe this is a workaround?
@@ -249,7 +249,7 @@ fn with_trailing_try_operator() {
         logger,
         &ranking_rule_universes[cur_ranking_rule_index],
     ) else {
-        return;
+        return
     };
 }
 

From 8f944d0bd15af955c0ac6adce8a797de9a6508aa Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 17 Apr 2024 18:41:14 -0400
Subject: [PATCH 3/6] Account for previous double-counting of semicolon size
 within format_expr

---
 src/config/mod.rs    |  2 +-
 src/expr.rs          |  6 ++++--
 src/stmt.rs          | 14 ++++++++++++--
 src/utils.rs         | 25 +++++++++++++++++++++++++
 tests/target/expr.rs |  8 ++++++--
 5 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/src/config/mod.rs b/src/config/mod.rs
index 04f4f212fc3..aa973e08646 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -673,7 +673,7 @@ force_multiline_blocks = false
 fn_params_layout = "Tall"
 brace_style = "SameLineWhere"
 control_brace_style = "AlwaysSameLine"
-trailing_semicolon = preserve
+trailing_semicolon = "Preserve"
 trailing_comma = "Vertical"
 match_block_trailing_comma = false
 blank_lines_upper_bound = 1
diff --git a/src/expr.rs b/src/expr.rs
index 6a21d88ac9d..ce93a3c7b5c 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -32,7 +32,7 @@ use crate::types::{rewrite_path, PathContext};
 use crate::utils::{
     colon_spaces, contains_skip, count_newlines, filtered_str_fits, first_line_ends_with,
     inner_attributes, last_line_extendable, last_line_width, mk_sp, outer_attributes,
-    semicolon_for_expr, unicode_str_width, wrap_str,
+    semicolon_for_expr_extra_hacky_double_counted_spacing, unicode_str_width, wrap_str,
 };
 use crate::vertical::rewrite_with_alignment;
 use crate::visitor::FmtVisitor;
@@ -64,7 +64,9 @@ pub(crate) fn format_expr(
     if contains_skip(&*expr.attrs) {
         return Some(context.snippet(expr.span()).to_owned());
     }
-    let shape = if expr_type == ExprType::Statement && semicolon_for_expr(context, expr) {
+    let shape = if expr_type == ExprType::Statement
+        && semicolon_for_expr_extra_hacky_double_counted_spacing(context, expr)
+    {
         shape.sub_width(1)?
     } else {
         shape
diff --git a/src/stmt.rs b/src/stmt.rs
index e3fe4ebca11..50b3eb86501 100644
--- a/src/stmt.rs
+++ b/src/stmt.rs
@@ -8,7 +8,7 @@ use crate::rewrite::{Rewrite, RewriteContext};
 use crate::shape::Shape;
 use crate::source_map::LineRangeUtils;
 use crate::spanned::Spanned;
-use crate::utils::semicolon_for_stmt;
+use crate::utils::{semicolon_for_expr, semicolon_for_stmt};
 
 pub(crate) struct Stmt<'a> {
     inner: &'a ast::Stmt,
@@ -116,7 +116,7 @@ fn format_stmt(
 
     let result = match stmt.kind {
         ast::StmtKind::Local(ref local) => local.rewrite(context, shape),
-        ast::StmtKind::Expr(ref ex) | ast::StmtKind::Semi(ref ex) => {
+        ast::StmtKind::Semi(ref ex) => {
             let suffix = if semicolon_for_stmt(context, stmt, is_last_expr) {
                 ";"
             } else {
@@ -126,6 +126,16 @@ fn format_stmt(
             let shape = shape.sub_width(suffix.len())?;
             format_expr(ex, expr_type, context, shape).map(|s| s + suffix)
         }
+        ast::StmtKind::Expr(ref ex) => {
+            let suffix = if semicolon_for_expr(context, ex) {
+                ";"
+            } else {
+                ""
+            };
+
+            let shape = shape.sub_width(suffix.len())?;
+            format_expr(ex, expr_type, context, shape).map(|s| s + suffix)
+        }
         ast::StmtKind::MacCall(..) | ast::StmtKind::Item(..) | ast::StmtKind::Empty => None,
     };
     result.and_then(|res| recover_comment_removed(res, stmt.span(), context))
diff --git a/src/utils.rs b/src/utils.rs
index 26d867a1761..56016425f9a 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -290,6 +290,31 @@ pub(crate) fn semicolon_for_expr(context: &RewriteContext<'_>, expr: &ast::Expr)
     }
 }
 
+/// Previously, we used to have `trailing_semicolon = always` enabled, and due to
+/// a bug between `format_stmt` and `format_expr`, we used to subtract the size of
+/// `;` *TWICE* from the shape. This means that an expr that would fit onto a line
+/// of, e.g. 99 (limit 100) after subtracting one for the semicolon would still be
+/// wrapped.
+///
+/// This function reimplements the old heuristic of double counting the "phantom"
+/// semicolon that should have already been accounted for, to not break existing
+/// formatting with the `trailing_semicolon = preserve` behavior.
+#[inline]
+pub(crate) fn semicolon_for_expr_extra_hacky_double_counted_spacing(
+    context: &RewriteContext<'_>,
+    expr: &ast::Expr,
+) -> bool {
+    match expr.kind {
+        ast::ExprKind::Ret(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Break(..) => {
+            match context.config.trailing_semicolon() {
+                TrailingSemicolon::Always | TrailingSemicolon::Preserve => true,
+                TrailingSemicolon::Never => false,
+            }
+        }
+        _ => false,
+    }
+}
+
 #[inline]
 pub(crate) fn semicolon_for_stmt(
     context: &RewriteContext<'_>,
diff --git a/tests/target/expr.rs b/tests/target/expr.rs
index 8ce3546f72a..8237c22c533 100644
--- a/tests/target/expr.rs
+++ b/tests/target/expr.rs
@@ -536,14 +536,18 @@ fn issue3226() {
     {
         {
             {
-                return Err(ErrorKind::ManagementInterfaceError("Server exited unexpectedly").into())
+                return Err(
+                    ErrorKind::ManagementInterfaceError("Server exited unexpectedly").into(),
+                )
             }
         }
     }
     {
         {
             {
-                break Err(ErrorKind::ManagementInterfaceError("Server exited unexpectedlyy").into())
+                break Err(
+                    ErrorKind::ManagementInterfaceError("Server exited unexpectedlyy").into(),
+                )
             }
         }
     }

From 3126770aa4d1c0e381f01e8c1fa73b854e786ad9 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 17 Apr 2024 21:08:24 -0400
Subject: [PATCH 4/6] Apply review comments

---
 Configurations.md                             | 19 +++++++++----------
 src/expr.rs                                   |  2 +-
 src/utils.rs                                  |  4 ++--
 tests/source/return-expr-version-one.rs       |  5 +++++
 .../configs/trailing_semicolon/always.rs      |  2 +-
 .../configs/trailing_semicolon/never.rs       |  2 +-
 .../configs/trailing_semicolon/preserve.rs    |  2 +-
 .../issue-5797/retain_trailing_semicolon.rs   |  2 +-
 tests/target/return-expr-version-one.rs       |  7 +++++++
 tests/target/return-expr-version-two.rs       |  5 +++++
 10 files changed, 33 insertions(+), 17 deletions(-)
 create mode 100644 tests/source/return-expr-version-one.rs
 create mode 100644 tests/target/return-expr-version-one.rs
 create mode 100644 tests/target/return-expr-version-two.rs

diff --git a/Configurations.md b/Configurations.md
index 6d858fb5da5..392e8d42bf8 100644
--- a/Configurations.md
+++ b/Configurations.md
@@ -2780,32 +2780,31 @@ See also: [`match_block_trailing_comma`](#match_block_trailing_comma).
 
 Add trailing semicolon after break, continue and return
 
-- **Default value**: `preserve`
-- **Possible values**: `always`, `never`, `preserve`
+- **Default value**: `Preserve`
+- **Possible values**: `Preserve`, `Always`, `Never`
 - **Stable**: No (tracking issue: [#3378](https://github.com/rust-lang/rustfmt/issues/3378))
 
-#### `always` (default):
+#### `Preserve` (default):
 ```rust
 fn foo() -> usize {
     return 0;
 }
-```
 
-#### `never`:
-```rust
-fn foo() -> usize {
+fn bar() -> usize {
     return 0
 }
 ```
 
-
-#### `preserve`:
+#### `Always`:
 ```rust
 fn foo() -> usize {
     return 0;
 }
+```
 
-fn bar() -> usize {
+#### `Never`:
+```rust
+fn foo() -> usize {
     return 0
 }
 ```
diff --git a/src/expr.rs b/src/expr.rs
index ce93a3c7b5c..a46cad28157 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -64,7 +64,7 @@ pub(crate) fn format_expr(
     if contains_skip(&*expr.attrs) {
         return Some(context.snippet(expr.span()).to_owned());
     }
-    let shape = if expr_type == ExprType::Statement
+    let shape = if context.config.version() == Version::One && expr_type == ExprType::Statement
         && semicolon_for_expr_extra_hacky_double_counted_spacing(context, expr)
     {
         shape.sub_width(1)?
diff --git a/src/utils.rs b/src/utils.rs
index 56016425f9a..63d374ee278 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -290,7 +290,7 @@ pub(crate) fn semicolon_for_expr(context: &RewriteContext<'_>, expr: &ast::Expr)
     }
 }
 
-/// Previously, we used to have `trailing_semicolon = always` enabled, and due to
+/// Previously, we used to have `trailing_semicolon = Always` enabled, and due to
 /// a bug between `format_stmt` and `format_expr`, we used to subtract the size of
 /// `;` *TWICE* from the shape. This means that an expr that would fit onto a line
 /// of, e.g. 99 (limit 100) after subtracting one for the semicolon would still be
@@ -298,7 +298,7 @@ pub(crate) fn semicolon_for_expr(context: &RewriteContext<'_>, expr: &ast::Expr)
 ///
 /// This function reimplements the old heuristic of double counting the "phantom"
 /// semicolon that should have already been accounted for, to not break existing
-/// formatting with the `trailing_semicolon = preserve` behavior.
+/// formatting with the `trailing_semicolon = Preserve` behavior for Version = One.
 #[inline]
 pub(crate) fn semicolon_for_expr_extra_hacky_double_counted_spacing(
     context: &RewriteContext<'_>,
diff --git a/tests/source/return-expr-version-one.rs b/tests/source/return-expr-version-one.rs
new file mode 100644
index 00000000000..ee2e0d355d8
--- /dev/null
+++ b/tests/source/return-expr-version-one.rs
@@ -0,0 +1,5 @@
+// rustfmt-version: One
+
+fn main() {
+    return hellooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(arg);
+}
diff --git a/tests/target/configs/trailing_semicolon/always.rs b/tests/target/configs/trailing_semicolon/always.rs
index 764ef8792bc..2f260b8e8bf 100644
--- a/tests/target/configs/trailing_semicolon/always.rs
+++ b/tests/target/configs/trailing_semicolon/always.rs
@@ -1,4 +1,4 @@
-// rustfmt-trailing_semicolon: always
+// rustfmt-trailing_semicolon: Always
 
 #![feature(loop_break_value)]
 
diff --git a/tests/target/configs/trailing_semicolon/never.rs b/tests/target/configs/trailing_semicolon/never.rs
index f4fce216f1a..b1a0e55b81a 100644
--- a/tests/target/configs/trailing_semicolon/never.rs
+++ b/tests/target/configs/trailing_semicolon/never.rs
@@ -1,4 +1,4 @@
-// rustfmt-trailing_semicolon: never
+// rustfmt-trailing_semicolon: Never
 
 #![feature(loop_break_value)]
 
diff --git a/tests/target/configs/trailing_semicolon/preserve.rs b/tests/target/configs/trailing_semicolon/preserve.rs
index 7804f230a81..b7074b877fd 100644
--- a/tests/target/configs/trailing_semicolon/preserve.rs
+++ b/tests/target/configs/trailing_semicolon/preserve.rs
@@ -1,4 +1,4 @@
-// rustfmt-trailing_semicolon: never
+// rustfmt-trailing_semicolon: Never
 
 #![feature(loop_break_value)]
 
diff --git a/tests/target/issue-5797/retain_trailing_semicolon.rs b/tests/target/issue-5797/retain_trailing_semicolon.rs
index 6eaf426cf5f..d01925505b6 100644
--- a/tests/target/issue-5797/retain_trailing_semicolon.rs
+++ b/tests/target/issue-5797/retain_trailing_semicolon.rs
@@ -1,4 +1,4 @@
-// rustfmt-trailing_semicolon: never
+// rustfmt-trailing_semicolon: Never
 
 fn foo() {}
 fn main() {
diff --git a/tests/target/return-expr-version-one.rs b/tests/target/return-expr-version-one.rs
new file mode 100644
index 00000000000..6bd8a52441f
--- /dev/null
+++ b/tests/target/return-expr-version-one.rs
@@ -0,0 +1,7 @@
+// rustfmt-version: One
+
+fn main() {
+    return hellooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(
+        arg,
+    );
+}
diff --git a/tests/target/return-expr-version-two.rs b/tests/target/return-expr-version-two.rs
new file mode 100644
index 00000000000..66fc5105d3f
--- /dev/null
+++ b/tests/target/return-expr-version-two.rs
@@ -0,0 +1,5 @@
+// rustfmt-version: Two
+
+fn main() {
+    return hellooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo(arg);
+}

From 922e8bad0a33586de16fe9410c167ac18df5055e Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 17 Apr 2024 21:08:28 -0400
Subject: [PATCH 5/6] Self format rustfmt

---
 src/closures.rs | 30 +++++++++++++-----------------
 src/expr.rs     |  3 ++-
 src/macros.rs   |  7 +------
 3 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/src/closures.rs b/src/closures.rs
index 5bf29441b54..52f17a2f09c 100644
--- a/src/closures.rs
+++ b/src/closures.rs
@@ -391,26 +391,22 @@ pub(crate) fn rewrite_last_closure(
 
         // We force to use block for the body of the closure for certain kinds of expressions.
         if is_block_closure_forced(context, body) {
-            return rewrite_closure_with_block(body, &prefix, context, body_shape).map(
-                |body_str| {
-                    match fn_decl.output {
-                        ast::FnRetTy::Default(..) if body_str.lines().count() <= 7 => {
-                            // If the expression can fit in a single line, we need not force block
-                            // closure.  However, if the closure has a return type, then we must
-                            // keep the blocks.
-                            match rewrite_closure_expr(body, &prefix, context, shape) {
-                                Some(single_line_body_str)
-                                    if !single_line_body_str.contains('\n') =>
-                                {
-                                    single_line_body_str
-                                }
-                                _ => body_str,
+            return rewrite_closure_with_block(body, &prefix, context, body_shape).map(|body_str| {
+                match fn_decl.output {
+                    ast::FnRetTy::Default(..) if body_str.lines().count() <= 7 => {
+                        // If the expression can fit in a single line, we need not force block
+                        // closure.  However, if the closure has a return type, then we must
+                        // keep the blocks.
+                        match rewrite_closure_expr(body, &prefix, context, shape) {
+                            Some(single_line_body_str) if !single_line_body_str.contains('\n') => {
+                                single_line_body_str
                             }
+                            _ => body_str,
                         }
-                        _ => body_str,
                     }
-                },
-            );
+                    _ => body_str,
+                }
+            });
         }
 
         // When overflowing the closure which consists of a single control flow expression,
diff --git a/src/expr.rs b/src/expr.rs
index a46cad28157..2a15ac08b2b 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -64,7 +64,8 @@ pub(crate) fn format_expr(
     if contains_skip(&*expr.attrs) {
         return Some(context.snippet(expr.span()).to_owned());
     }
-    let shape = if context.config.version() == Version::One && expr_type == ExprType::Statement
+    let shape = if context.config.version() == Version::One
+        && expr_type == ExprType::Statement
         && semicolon_for_expr_extra_hacky_double_counted_spacing(context, expr)
     {
         shape.sub_width(1)?
diff --git a/src/macros.rs b/src/macros.rs
index 6e114c76f26..3329f9a2db6 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -240,12 +240,7 @@ fn rewrite_macro_inner(
     } = match parse_macro_args(context, ts, style, is_forced_bracket) {
         Some(args) => args,
         None => {
-            return return_macro_parse_failure_fallback(
-                context,
-                shape.indent,
-                position,
-                mac.span(),
-            );
+            return return_macro_parse_failure_fallback(context, shape.indent, position, mac.span());
         }
     };
 

From 1973b90ba986ef109326cd4f10956f21c169d3ee Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 17 Apr 2024 21:14:54 -0400
Subject: [PATCH 6/6] Comments

---
 src/config/options.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/config/options.rs b/src/config/options.rs
index 04c78ffc39a..d3902e49cab 100644
--- a/src/config/options.rs
+++ b/src/config/options.rs
@@ -50,9 +50,15 @@ pub enum ControlBraceStyle {
 }
 
 #[config_type]
+/// How to treat the semicolon that is optional for final diverging expressions
+/// (`return`/`break`/`continue`).
 pub enum TrailingSemicolon {
+    /// Always rewrite `return;` and `break;` expressions to have a trailing semicolon,
+    /// unless the block is a single-line block, e.g. `let PAT = e else { return }`.
     Always,
+    /// Always return `return` and `break` expressions to remove the trailing semicolon.
     Never,
+    /// Preserve an existing trailing semicolon if it exists.
     Preserve,
 }