From beb37b0dcbd7ca886c6533f5e2a7d637d951780a Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Mon, 10 Feb 2025 20:48:24 +0900
Subject: [PATCH 1/8] chore: add rewrite_last_closure log similar to
 rewrite_closure

---
 src/closures.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/closures.rs b/src/closures.rs
index 1f59fbc2960..182eb6e3865 100644
--- a/src/closures.rs
+++ b/src/closures.rs
@@ -353,6 +353,8 @@ pub(crate) fn rewrite_last_closure(
     expr: &ast::Expr,
     shape: Shape,
 ) -> RewriteResult {
+    debug!("rewrite_last_closure {:?}", expr);
+
     if let ast::ExprKind::Closure(ref closure) = expr.kind {
         let ast::Closure {
             ref binder,

From 3df823283201b703f70acb5612bb9d5d36a76961 Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Mon, 10 Feb 2025 21:03:30 +0900
Subject: [PATCH 2/8] fix: labels on the closure body can be disappearing

---
 src/closures.rs | 43 ++++++++++++++++++++++++++++++-------------
 1 file changed, 30 insertions(+), 13 deletions(-)

diff --git a/src/closures.rs b/src/closures.rs
index 182eb6e3865..8dc4bc867a1 100644
--- a/src/closures.rs
+++ b/src/closures.rs
@@ -1,4 +1,4 @@
-use rustc_ast::{ast, ptr};
+use rustc_ast::{Label, ast, ptr};
 use rustc_span::Span;
 use thin_vec::thin_vec;
 use tracing::debug;
@@ -55,7 +55,7 @@ pub(crate) fn rewrite_closure(
     // 1 = space between `|...|` and body.
     let body_shape = shape.offset_left(extra_offset, span)?;
 
-    if let ast::ExprKind::Block(ref block, _) = body.kind {
+    if let ast::ExprKind::Block(ref block, ref label) = body.kind {
         // The body of the closure is an empty block.
         if block.stmts.is_empty() && !block_contains_comment(context, block) {
             return body
@@ -72,7 +72,7 @@ pub(crate) fn rewrite_closure(
 
         result.or_else(|_| {
             // Either we require a block, or tried without and failed.
-            rewrite_closure_block(block, &prefix, context, body_shape)
+            rewrite_closure_block(block, label, &prefix, context, body_shape)
         })
     } else {
         rewrite_closure_expr(body, &prefix, context, body_shape).or_else(|_| {
@@ -104,8 +104,8 @@ fn get_inner_expr<'a>(
     prefix: &str,
     context: &RewriteContext<'_>,
 ) -> &'a ast::Expr {
-    if let ast::ExprKind::Block(ref block, _) = expr.kind {
-        if !needs_block(block, prefix, context) {
+    if let ast::ExprKind::Block(ref block, ref label) = expr.kind {
+        if !needs_block(block, label, prefix, context) {
             // block.stmts.len() == 1 except with `|| {{}}`;
             // https://github.com/rust-lang/rustfmt/issues/3844
             if let Some(expr) = block.stmts.first().and_then(stmt_expr) {
@@ -118,7 +118,12 @@ fn get_inner_expr<'a>(
 }
 
 // Figure out if a block is necessary.
-fn needs_block(block: &ast::Block, prefix: &str, context: &RewriteContext<'_>) -> bool {
+fn needs_block(
+    block: &ast::Block,
+    label: &Option<Label>,
+    prefix: &str,
+    context: &RewriteContext<'_>,
+) -> bool {
     let has_attributes = block.stmts.first().map_or(false, |first_stmt| {
         !get_attrs_from_stmt(first_stmt).is_empty()
     });
@@ -128,6 +133,7 @@ fn needs_block(block: &ast::Block, prefix: &str, context: &RewriteContext<'_>) -
         || has_attributes
         || block_contains_comment(context, block)
         || prefix.contains('\n')
+        || label.is_some()
 }
 
 fn veto_block(e: &ast::Expr) -> bool {
@@ -231,15 +237,25 @@ fn rewrite_closure_expr(
 // Rewrite closure whose body is block.
 fn rewrite_closure_block(
     block: &ast::Block,
+    label: &Option<Label>,
     prefix: &str,
     context: &RewriteContext<'_>,
     shape: Shape,
 ) -> RewriteResult {
-    Ok(format!(
-        "{} {}",
-        prefix,
-        block.rewrite_result(context, shape)?
-    ))
+    if let Some(label) = label {
+        Ok(format!(
+            "{} {}: {}",
+            prefix,
+            context.snippet(label.ident.span),
+            block.rewrite_result(context, shape)?
+        ))
+    } else {
+        Ok(format!(
+            "{} {}",
+            prefix,
+            block.rewrite_result(context, shape)?
+        ))
+    }
 }
 
 // Return type is (prefix, extra_offset)
@@ -368,10 +384,11 @@ pub(crate) fn rewrite_last_closure(
             fn_arg_span: _,
         } = **closure;
         let body = match body.kind {
-            ast::ExprKind::Block(ref block, _)
+            ast::ExprKind::Block(ref block, ref label)
                 if !is_unsafe_block(block)
                     && !context.inside_macro()
-                    && is_simple_block(context, block, Some(&body.attrs)) =>
+                    && is_simple_block(context, block, Some(&body.attrs))
+                    && label.is_none() =>
             {
                 stmt_expr(&block.stmts[0]).unwrap_or(body)
             }

From 2b886890a84ee1461d59c10a57edfe15dd48e720 Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Mon, 10 Feb 2025 21:14:42 +0900
Subject: [PATCH 3/8] test: add tests for labels on closure block

---
 tests/source/closure-block-labels.rs | 246 +++++++++++++++++++++++++
 tests/target/closure-block-labels.rs | 259 +++++++++++++++++++++++++++
 2 files changed, 505 insertions(+)
 create mode 100644 tests/source/closure-block-labels.rs
 create mode 100644 tests/target/closure-block-labels.rs

diff --git a/tests/source/closure-block-labels.rs b/tests/source/closure-block-labels.rs
new file mode 100644
index 00000000000..0e41e3ed57b
--- /dev/null
+++ b/tests/source/closure-block-labels.rs
@@ -0,0 +1,246 @@
+macro_rules! test_macro {
+    (|$transaction: ident| $body: expr) => {{
+        let $transaction = some_value;
+        let _ = $body;
+    }};
+}
+
+fn test_func<T>(func: impl FnOnce(u8) -> T) {
+}
+
+fn test_func2<T>(func: impl FnOnce(u8) -> T, value: u8) {
+}
+
+// _0: in-macro
+// _1: last argument in function invocation
+// _2: non-last argument in function invocation
+// _3: simple expression
+
+// test0: the cause reported in issue: label is used, and there is usage, multiple statements
+pub fn rustfnmt_test0_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_2(condition: bool) {
+    test_func2(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    }, 0);
+}
+
+pub fn rustfnmt_test0_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    };
+}
+
+// test0: the cause reported in issue: label is used, and there is usage, multiple statements
+pub fn rustfnmt_test0_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_2(condition: bool) {
+    test_func2(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    }, 0);
+}
+
+pub fn rustfnmt_test0_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    };
+}
+
+
+// test1: label is unused, and there is usage, multiple statements
+pub fn rustfnmt_test1_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            todo!("");
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test1_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            todo!("");
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test1_2(condition: bool) {
+    test_func2(|transaction| 'block: {
+        if condition {
+            todo!("");
+        }
+
+        todo!()
+    }, 0);
+}
+
+pub fn rustfnmt_test1_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            todo!("");
+        }
+
+        todo!()
+    };
+}
+
+
+
+// test2: label is used, single expression
+pub fn rustfnmt_test2_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        break 'block 0;
+    });
+}
+
+pub fn rustfnmt_test2_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        break 'block 0;
+    });
+}
+
+pub fn rustfnmt_test2_2(condition: bool) {
+    test_func2(|transaction| 'block: {
+        break 'block 0;
+    }, 0);
+}
+
+pub fn rustfnmt_test2_3(condition: bool) {
+    let x = |transaction| 'block: {
+        break 'block 0;
+    };
+}
+
+// test3: label is unused, single general multi-line expression
+pub fn rustfnmt_test3_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        vec![
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0,
+        ]
+    });
+}
+
+pub fn rustfnmt_test3_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        vec![
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0,
+        ]
+    });
+}
+
+pub fn rustfnmt_test3_2(condition: bool) {
+    test_func2(|transaction| 'block: {
+        vec![
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0,
+        ]
+    }, 0);
+}
+
+pub fn rustfnmt_test3_3(condition: bool) {
+    let x = |transaction| 'block: {
+        vec![
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0,
+        ]
+    };
+}
+
+// test4: label is unused, single block statement-expression
+pub fn rustfnmt_test4_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            break 'block 1;
+        } else {
+            break 'block 0;
+        }
+    });
+}
+
+pub fn rustfnmt_test4_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            break 'block 1;
+        } else {
+            break 'block 0;
+        }
+    });
+}
+
+pub fn rustfnmt_test4_2(condition: bool) {
+    test_func2(|transaction| 'block: {
+        if condition {
+            break 'block 1;
+        } else {
+            break 'block 0;
+        }
+    }, 1);
+}
+
+pub fn rustfnmt_test4_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            break 'block 1;
+        } else {
+            break 'block 0;
+        }
+    };
+}
diff --git a/tests/target/closure-block-labels.rs b/tests/target/closure-block-labels.rs
new file mode 100644
index 00000000000..e5b6f1fcb69
--- /dev/null
+++ b/tests/target/closure-block-labels.rs
@@ -0,0 +1,259 @@
+macro_rules! test_macro {
+    (|$transaction: ident| $body: expr) => {{
+        let $transaction = some_value;
+        let _ = $body;
+    }};
+}
+
+fn test_func<T>(func: impl FnOnce(u8) -> T) {}
+
+fn test_func2<T>(func: impl FnOnce(u8) -> T, value: u8) {}
+
+// _0: in-macro
+// _1: last argument in function invocation
+// _2: non-last argument in function invocation
+// _3: simple expression
+
+// test0: the cause reported in issue: label is used, and there is usage, multiple statements
+pub fn rustfnmt_test0_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_2(condition: bool) {
+    test_func2(
+        |transaction| 'block: {
+            if condition {
+                break 'block 0;
+            }
+
+            todo!()
+        },
+        0,
+    );
+}
+
+pub fn rustfnmt_test0_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    };
+}
+
+// test0: the cause reported in issue: label is used, and there is usage, multiple statements
+pub fn rustfnmt_test0_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test0_2(condition: bool) {
+    test_func2(
+        |transaction| 'block: {
+            if condition {
+                break 'block 0;
+            }
+
+            todo!()
+        },
+        0,
+    );
+}
+
+pub fn rustfnmt_test0_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            break 'block 0;
+        }
+
+        todo!()
+    };
+}
+
+// test1: label is unused, and there is usage, multiple statements
+pub fn rustfnmt_test1_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            todo!("");
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test1_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            todo!("");
+        }
+
+        todo!()
+    });
+}
+
+pub fn rustfnmt_test1_2(condition: bool) {
+    test_func2(
+        |transaction| 'block: {
+            if condition {
+                todo!("");
+            }
+
+            todo!()
+        },
+        0,
+    );
+}
+
+pub fn rustfnmt_test1_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            todo!("");
+        }
+
+        todo!()
+    };
+}
+
+// test2: label is used, single expression
+pub fn rustfnmt_test2_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        break 'block 0;
+    });
+}
+
+pub fn rustfnmt_test2_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        break 'block 0;
+    });
+}
+
+pub fn rustfnmt_test2_2(condition: bool) {
+    test_func2(
+        |transaction| 'block: {
+            break 'block 0;
+        },
+        0,
+    );
+}
+
+pub fn rustfnmt_test2_3(condition: bool) {
+    let x = |transaction| 'block: {
+        break 'block 0;
+    };
+}
+
+// test3: label is unused, single general multi-line expression
+pub fn rustfnmt_test3_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        vec![
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0,
+        ]
+    });
+}
+
+pub fn rustfnmt_test3_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        vec![
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0,
+        ]
+    });
+}
+
+pub fn rustfnmt_test3_2(condition: bool) {
+    test_func2(
+        |transaction| 'block: {
+            vec![
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                0, 0,
+            ]
+        },
+        0,
+    );
+}
+
+pub fn rustfnmt_test3_3(condition: bool) {
+    let x = |transaction| 'block: {
+        vec![
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0,
+        ]
+    };
+}
+
+// test4: label is unused, single block statement-expression
+pub fn rustfnmt_test4_0(condition: bool) {
+    test_macro!(|transaction| 'block: {
+        if condition {
+            break 'block 1;
+        } else {
+            break 'block 0;
+        }
+    });
+}
+
+pub fn rustfnmt_test4_1(condition: bool) {
+    test_func(|transaction| 'block: {
+        if condition {
+            break 'block 1;
+        } else {
+            break 'block 0;
+        }
+    });
+}
+
+pub fn rustfnmt_test4_2(condition: bool) {
+    test_func2(
+        |transaction| 'block: {
+            if condition {
+                break 'block 1;
+            } else {
+                break 'block 0;
+            }
+        },
+        1,
+    );
+}
+
+pub fn rustfnmt_test4_3(condition: bool) {
+    let x = |transaction| 'block: {
+        if condition {
+            break 'block 1;
+        } else {
+            break 'block 0;
+        }
+    };
+}

From 75c514265cf15ef2cdaccb4be355acb541ea0a28 Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Tue, 11 Feb 2025 23:04:57 +0900
Subject: [PATCH 4/8] chore: make rewrite_closure_block accept Expr and pass
 the entire body

---
 src/closures.rs | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/src/closures.rs b/src/closures.rs
index 8dc4bc867a1..0c1ff990b9d 100644
--- a/src/closures.rs
+++ b/src/closures.rs
@@ -55,7 +55,7 @@ pub(crate) fn rewrite_closure(
     // 1 = space between `|...|` and body.
     let body_shape = shape.offset_left(extra_offset, span)?;
 
-    if let ast::ExprKind::Block(ref block, ref label) = body.kind {
+    if let ast::ExprKind::Block(ref block, _) = body.kind {
         // The body of the closure is an empty block.
         if block.stmts.is_empty() && !block_contains_comment(context, block) {
             return body
@@ -72,7 +72,7 @@ pub(crate) fn rewrite_closure(
 
         result.or_else(|_| {
             // Either we require a block, or tried without and failed.
-            rewrite_closure_block(block, label, &prefix, context, body_shape)
+            rewrite_closure_block(body, &prefix, context, body_shape)
         })
     } else {
         rewrite_closure_expr(body, &prefix, context, body_shape).or_else(|_| {
@@ -236,26 +236,16 @@ fn rewrite_closure_expr(
 
 // Rewrite closure whose body is block.
 fn rewrite_closure_block(
-    block: &ast::Block,
-    label: &Option<Label>,
+    block: &ast::Expr,
     prefix: &str,
     context: &RewriteContext<'_>,
     shape: Shape,
 ) -> RewriteResult {
-    if let Some(label) = label {
-        Ok(format!(
-            "{} {}: {}",
-            prefix,
-            context.snippet(label.ident.span),
-            block.rewrite_result(context, shape)?
-        ))
-    } else {
-        Ok(format!(
-            "{} {}",
-            prefix,
-            block.rewrite_result(context, shape)?
-        ))
-    }
+    Ok(format!(
+        "{} {}",
+        prefix,
+        block.rewrite_result(context, shape)?
+    ))
 }
 
 // Return type is (prefix, extra_offset)

From 2aaec6e7d349c29c35dc9ceacd98294d5f63177c Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Tue, 11 Feb 2025 23:06:42 +0900
Subject: [PATCH 5/8] test: fix duplicated test cause

---
 tests/source/closure-block-labels.rs | 41 --------------------------
 tests/target/closure-block-labels.rs | 44 ----------------------------
 2 files changed, 85 deletions(-)

diff --git a/tests/source/closure-block-labels.rs b/tests/source/closure-block-labels.rs
index 0e41e3ed57b..728d0f878b8 100644
--- a/tests/source/closure-block-labels.rs
+++ b/tests/source/closure-block-labels.rs
@@ -57,47 +57,6 @@ pub fn rustfnmt_test0_3(condition: bool) {
     };
 }
 
-// test0: the cause reported in issue: label is used, and there is usage, multiple statements
-pub fn rustfnmt_test0_0(condition: bool) {
-    test_macro!(|transaction| 'block: {
-        if condition {
-            break 'block 0;
-        }
-
-        todo!()
-    });
-}
-
-pub fn rustfnmt_test0_1(condition: bool) {
-    test_func(|transaction| 'block: {
-        if condition {
-            break 'block 0;
-        }
-
-        todo!()
-    });
-}
-
-pub fn rustfnmt_test0_2(condition: bool) {
-    test_func2(|transaction| 'block: {
-        if condition {
-            break 'block 0;
-        }
-
-        todo!()
-    }, 0);
-}
-
-pub fn rustfnmt_test0_3(condition: bool) {
-    let x = |transaction| 'block: {
-        if condition {
-            break 'block 0;
-        }
-
-        todo!()
-    };
-}
-
 
 // test1: label is unused, and there is usage, multiple statements
 pub fn rustfnmt_test1_0(condition: bool) {
diff --git a/tests/target/closure-block-labels.rs b/tests/target/closure-block-labels.rs
index e5b6f1fcb69..2cde4bdcc22 100644
--- a/tests/target/closure-block-labels.rs
+++ b/tests/target/closure-block-labels.rs
@@ -58,50 +58,6 @@ pub fn rustfnmt_test0_3(condition: bool) {
     };
 }
 
-// test0: the cause reported in issue: label is used, and there is usage, multiple statements
-pub fn rustfnmt_test0_0(condition: bool) {
-    test_macro!(|transaction| 'block: {
-        if condition {
-            break 'block 0;
-        }
-
-        todo!()
-    });
-}
-
-pub fn rustfnmt_test0_1(condition: bool) {
-    test_func(|transaction| 'block: {
-        if condition {
-            break 'block 0;
-        }
-
-        todo!()
-    });
-}
-
-pub fn rustfnmt_test0_2(condition: bool) {
-    test_func2(
-        |transaction| 'block: {
-            if condition {
-                break 'block 0;
-            }
-
-            todo!()
-        },
-        0,
-    );
-}
-
-pub fn rustfnmt_test0_3(condition: bool) {
-    let x = |transaction| 'block: {
-        if condition {
-            break 'block 0;
-        }
-
-        todo!()
-    };
-}
-
 // test1: label is unused, and there is usage, multiple statements
 pub fn rustfnmt_test1_0(condition: bool) {
     test_macro!(|transaction| 'block: {

From 75b1cc42a64be93ba1646fac864700313a109b9d Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Tue, 11 Feb 2025 23:07:12 +0900
Subject: [PATCH 6/8] test: fix typo in test causes

---
 tests/source/closure-block-labels.rs | 40 ++++++++++++++--------------
 tests/target/closure-block-labels.rs | 40 ++++++++++++++--------------
 2 files changed, 40 insertions(+), 40 deletions(-)

diff --git a/tests/source/closure-block-labels.rs b/tests/source/closure-block-labels.rs
index 728d0f878b8..3fd0c949fba 100644
--- a/tests/source/closure-block-labels.rs
+++ b/tests/source/closure-block-labels.rs
@@ -17,7 +17,7 @@ fn test_func2<T>(func: impl FnOnce(u8) -> T, value: u8) {
 // _3: simple expression
 
 // test0: the cause reported in issue: label is used, and there is usage, multiple statements
-pub fn rustfnmt_test0_0(condition: bool) {
+pub fn rustfmt_test0_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         if condition {
             break 'block 0;
@@ -27,7 +27,7 @@ pub fn rustfnmt_test0_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test0_1(condition: bool) {
+pub fn rustfmt_test0_1(condition: bool) {
     test_func(|transaction| 'block: {
         if condition {
             break 'block 0;
@@ -37,7 +37,7 @@ pub fn rustfnmt_test0_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test0_2(condition: bool) {
+pub fn rustfmt_test0_2(condition: bool) {
     test_func2(|transaction| 'block: {
         if condition {
             break 'block 0;
@@ -47,7 +47,7 @@ pub fn rustfnmt_test0_2(condition: bool) {
     }, 0);
 }
 
-pub fn rustfnmt_test0_3(condition: bool) {
+pub fn rustfmt_test0_3(condition: bool) {
     let x = |transaction| 'block: {
         if condition {
             break 'block 0;
@@ -59,7 +59,7 @@ pub fn rustfnmt_test0_3(condition: bool) {
 
 
 // test1: label is unused, and there is usage, multiple statements
-pub fn rustfnmt_test1_0(condition: bool) {
+pub fn rustfmt_test1_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         if condition {
             todo!("");
@@ -69,7 +69,7 @@ pub fn rustfnmt_test1_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test1_1(condition: bool) {
+pub fn rustfmt_test1_1(condition: bool) {
     test_func(|transaction| 'block: {
         if condition {
             todo!("");
@@ -79,7 +79,7 @@ pub fn rustfnmt_test1_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test1_2(condition: bool) {
+pub fn rustfmt_test1_2(condition: bool) {
     test_func2(|transaction| 'block: {
         if condition {
             todo!("");
@@ -89,7 +89,7 @@ pub fn rustfnmt_test1_2(condition: bool) {
     }, 0);
 }
 
-pub fn rustfnmt_test1_3(condition: bool) {
+pub fn rustfmt_test1_3(condition: bool) {
     let x = |transaction| 'block: {
         if condition {
             todo!("");
@@ -102,32 +102,32 @@ pub fn rustfnmt_test1_3(condition: bool) {
 
 
 // test2: label is used, single expression
-pub fn rustfnmt_test2_0(condition: bool) {
+pub fn rustfmt_test2_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         break 'block 0;
     });
 }
 
-pub fn rustfnmt_test2_1(condition: bool) {
+pub fn rustfmt_test2_1(condition: bool) {
     test_func(|transaction| 'block: {
         break 'block 0;
     });
 }
 
-pub fn rustfnmt_test2_2(condition: bool) {
+pub fn rustfmt_test2_2(condition: bool) {
     test_func2(|transaction| 'block: {
         break 'block 0;
     }, 0);
 }
 
-pub fn rustfnmt_test2_3(condition: bool) {
+pub fn rustfmt_test2_3(condition: bool) {
     let x = |transaction| 'block: {
         break 'block 0;
     };
 }
 
 // test3: label is unused, single general multi-line expression
-pub fn rustfnmt_test3_0(condition: bool) {
+pub fn rustfmt_test3_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         vec![
             0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -136,7 +136,7 @@ pub fn rustfnmt_test3_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test3_1(condition: bool) {
+pub fn rustfmt_test3_1(condition: bool) {
     test_func(|transaction| 'block: {
         vec![
             0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -145,7 +145,7 @@ pub fn rustfnmt_test3_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test3_2(condition: bool) {
+pub fn rustfmt_test3_2(condition: bool) {
     test_func2(|transaction| 'block: {
         vec![
             0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -154,7 +154,7 @@ pub fn rustfnmt_test3_2(condition: bool) {
     }, 0);
 }
 
-pub fn rustfnmt_test3_3(condition: bool) {
+pub fn rustfmt_test3_3(condition: bool) {
     let x = |transaction| 'block: {
         vec![
             0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -164,7 +164,7 @@ pub fn rustfnmt_test3_3(condition: bool) {
 }
 
 // test4: label is unused, single block statement-expression
-pub fn rustfnmt_test4_0(condition: bool) {
+pub fn rustfmt_test4_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         if condition {
             break 'block 1;
@@ -174,7 +174,7 @@ pub fn rustfnmt_test4_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test4_1(condition: bool) {
+pub fn rustfmt_test4_1(condition: bool) {
     test_func(|transaction| 'block: {
         if condition {
             break 'block 1;
@@ -184,7 +184,7 @@ pub fn rustfnmt_test4_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test4_2(condition: bool) {
+pub fn rustfmt_test4_2(condition: bool) {
     test_func2(|transaction| 'block: {
         if condition {
             break 'block 1;
@@ -194,7 +194,7 @@ pub fn rustfnmt_test4_2(condition: bool) {
     }, 1);
 }
 
-pub fn rustfnmt_test4_3(condition: bool) {
+pub fn rustfmt_test4_3(condition: bool) {
     let x = |transaction| 'block: {
         if condition {
             break 'block 1;
diff --git a/tests/target/closure-block-labels.rs b/tests/target/closure-block-labels.rs
index 2cde4bdcc22..c9ab3abaa13 100644
--- a/tests/target/closure-block-labels.rs
+++ b/tests/target/closure-block-labels.rs
@@ -15,7 +15,7 @@ fn test_func2<T>(func: impl FnOnce(u8) -> T, value: u8) {}
 // _3: simple expression
 
 // test0: the cause reported in issue: label is used, and there is usage, multiple statements
-pub fn rustfnmt_test0_0(condition: bool) {
+pub fn rustfmt_test0_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         if condition {
             break 'block 0;
@@ -25,7 +25,7 @@ pub fn rustfnmt_test0_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test0_1(condition: bool) {
+pub fn rustfmt_test0_1(condition: bool) {
     test_func(|transaction| 'block: {
         if condition {
             break 'block 0;
@@ -35,7 +35,7 @@ pub fn rustfnmt_test0_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test0_2(condition: bool) {
+pub fn rustfmt_test0_2(condition: bool) {
     test_func2(
         |transaction| 'block: {
             if condition {
@@ -48,7 +48,7 @@ pub fn rustfnmt_test0_2(condition: bool) {
     );
 }
 
-pub fn rustfnmt_test0_3(condition: bool) {
+pub fn rustfmt_test0_3(condition: bool) {
     let x = |transaction| 'block: {
         if condition {
             break 'block 0;
@@ -59,7 +59,7 @@ pub fn rustfnmt_test0_3(condition: bool) {
 }
 
 // test1: label is unused, and there is usage, multiple statements
-pub fn rustfnmt_test1_0(condition: bool) {
+pub fn rustfmt_test1_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         if condition {
             todo!("");
@@ -69,7 +69,7 @@ pub fn rustfnmt_test1_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test1_1(condition: bool) {
+pub fn rustfmt_test1_1(condition: bool) {
     test_func(|transaction| 'block: {
         if condition {
             todo!("");
@@ -79,7 +79,7 @@ pub fn rustfnmt_test1_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test1_2(condition: bool) {
+pub fn rustfmt_test1_2(condition: bool) {
     test_func2(
         |transaction| 'block: {
             if condition {
@@ -92,7 +92,7 @@ pub fn rustfnmt_test1_2(condition: bool) {
     );
 }
 
-pub fn rustfnmt_test1_3(condition: bool) {
+pub fn rustfmt_test1_3(condition: bool) {
     let x = |transaction| 'block: {
         if condition {
             todo!("");
@@ -103,19 +103,19 @@ pub fn rustfnmt_test1_3(condition: bool) {
 }
 
 // test2: label is used, single expression
-pub fn rustfnmt_test2_0(condition: bool) {
+pub fn rustfmt_test2_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         break 'block 0;
     });
 }
 
-pub fn rustfnmt_test2_1(condition: bool) {
+pub fn rustfmt_test2_1(condition: bool) {
     test_func(|transaction| 'block: {
         break 'block 0;
     });
 }
 
-pub fn rustfnmt_test2_2(condition: bool) {
+pub fn rustfmt_test2_2(condition: bool) {
     test_func2(
         |transaction| 'block: {
             break 'block 0;
@@ -124,14 +124,14 @@ pub fn rustfnmt_test2_2(condition: bool) {
     );
 }
 
-pub fn rustfnmt_test2_3(condition: bool) {
+pub fn rustfmt_test2_3(condition: bool) {
     let x = |transaction| 'block: {
         break 'block 0;
     };
 }
 
 // test3: label is unused, single general multi-line expression
-pub fn rustfnmt_test3_0(condition: bool) {
+pub fn rustfmt_test3_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         vec![
             0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -140,7 +140,7 @@ pub fn rustfnmt_test3_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test3_1(condition: bool) {
+pub fn rustfmt_test3_1(condition: bool) {
     test_func(|transaction| 'block: {
         vec![
             0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -149,7 +149,7 @@ pub fn rustfnmt_test3_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test3_2(condition: bool) {
+pub fn rustfmt_test3_2(condition: bool) {
     test_func2(
         |transaction| 'block: {
             vec![
@@ -161,7 +161,7 @@ pub fn rustfnmt_test3_2(condition: bool) {
     );
 }
 
-pub fn rustfnmt_test3_3(condition: bool) {
+pub fn rustfmt_test3_3(condition: bool) {
     let x = |transaction| 'block: {
         vec![
             0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -171,7 +171,7 @@ pub fn rustfnmt_test3_3(condition: bool) {
 }
 
 // test4: label is unused, single block statement-expression
-pub fn rustfnmt_test4_0(condition: bool) {
+pub fn rustfmt_test4_0(condition: bool) {
     test_macro!(|transaction| 'block: {
         if condition {
             break 'block 1;
@@ -181,7 +181,7 @@ pub fn rustfnmt_test4_0(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test4_1(condition: bool) {
+pub fn rustfmt_test4_1(condition: bool) {
     test_func(|transaction| 'block: {
         if condition {
             break 'block 1;
@@ -191,7 +191,7 @@ pub fn rustfnmt_test4_1(condition: bool) {
     });
 }
 
-pub fn rustfnmt_test4_2(condition: bool) {
+pub fn rustfmt_test4_2(condition: bool) {
     test_func2(
         |transaction| 'block: {
             if condition {
@@ -204,7 +204,7 @@ pub fn rustfnmt_test4_2(condition: bool) {
     );
 }
 
-pub fn rustfnmt_test4_3(condition: bool) {
+pub fn rustfmt_test4_3(condition: bool) {
     let x = |transaction| 'block: {
         if condition {
             break 'block 1;

From 39ebb96ef085e5cc5a7c48faec105f1c9e457df6 Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Tue, 11 Feb 2025 23:08:24 +0900
Subject: [PATCH 7/8] test: remove unnecessary helpers

---
 tests/source/closure-block-labels.rs | 13 -------------
 tests/target/closure-block-labels.rs | 11 -----------
 2 files changed, 24 deletions(-)

diff --git a/tests/source/closure-block-labels.rs b/tests/source/closure-block-labels.rs
index 3fd0c949fba..76af1f8c972 100644
--- a/tests/source/closure-block-labels.rs
+++ b/tests/source/closure-block-labels.rs
@@ -1,16 +1,3 @@
-macro_rules! test_macro {
-    (|$transaction: ident| $body: expr) => {{
-        let $transaction = some_value;
-        let _ = $body;
-    }};
-}
-
-fn test_func<T>(func: impl FnOnce(u8) -> T) {
-}
-
-fn test_func2<T>(func: impl FnOnce(u8) -> T, value: u8) {
-}
-
 // _0: in-macro
 // _1: last argument in function invocation
 // _2: non-last argument in function invocation
diff --git a/tests/target/closure-block-labels.rs b/tests/target/closure-block-labels.rs
index c9ab3abaa13..a7ebc3a22b8 100644
--- a/tests/target/closure-block-labels.rs
+++ b/tests/target/closure-block-labels.rs
@@ -1,14 +1,3 @@
-macro_rules! test_macro {
-    (|$transaction: ident| $body: expr) => {{
-        let $transaction = some_value;
-        let _ = $body;
-    }};
-}
-
-fn test_func<T>(func: impl FnOnce(u8) -> T) {}
-
-fn test_func2<T>(func: impl FnOnce(u8) -> T, value: u8) {}
-
 // _0: in-macro
 // _1: last argument in function invocation
 // _2: non-last argument in function invocation

From 2cfbf1cd6ef9c01cc1446df3a866bca774add05d Mon Sep 17 00:00:00 2001
From: anatawa12 <anatawa12@icloud.com>
Date: Wed, 12 Feb 2025 15:54:59 +0900
Subject: [PATCH 8/8] chore: add debug_assert for precondition

---
 src/closures.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/closures.rs b/src/closures.rs
index 0c1ff990b9d..296b7407e40 100644
--- a/src/closures.rs
+++ b/src/closures.rs
@@ -241,6 +241,11 @@ fn rewrite_closure_block(
     context: &RewriteContext<'_>,
     shape: Shape,
 ) -> RewriteResult {
+    debug_assert!(
+        matches!(block.kind, ast::ExprKind::Block(..)),
+        "expected a block expression"
+    );
+
     Ok(format!(
         "{} {}",
         prefix,