Keep code after a single-line comment before do or after (

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed a single-line comment before `do` in a numeric `for` loop, or right after the opening parenthesis of a hanging condition, commenting out the code that followed it ([#1176](https://github.com/JohnnyMorganz/StyLua/issues/1176))
+
 ## [2.6.0] - 2026-10-10
 
 ### Added

src/formatters/expression.rs

@@ -1422,7 +1422,12 @@ fn format_hanging_expression_(
                 let formatted_expression = format_expression(ctx, expression, lhs_shape + 1); // 1 = opening parentheses
 
                 let expression_str = formatted_expression.to_string();
+                // A single-line comment after the opening parenthesis needs the expression on the next line
                 if !contains_comments(expression)
+                    && !contained
+                        .tokens()
+                        .0
+                        .has_trailing_comments(CommentSearch::Single)
                     && !lhs_shape.add_width(2 + expression_str.len()).over_budget()
                 {
                     // The expression inside the parentheses is small, we do not need to break it down further

src/formatters/stmt.rs

@@ -785,8 +785,41 @@ pub fn format_numeric_for(ctx: &Context, numeric_for: &NumericFor, shape: Shape)
         _ => unreachable!("Got numeric for end step comma with no step or vice versa"),
     };
 
-    let do_token = fmt_symbol!(ctx, numeric_for.do_token(), " do", shape)
-        .update_trailing_trivia(FormatTriviaType::Append(trailing_trivia.to_owned()));
+    // A single-line comment before `do` would comment it out, so put `do` on its own line,
+    // as for `while` and generic `for`
+    let do_on_own_line = numeric_for
+        .step()
+        .unwrap_or(numeric_for.end())
+        .has_trailing_comments(CommentSearch::Single)
+        || numeric_for
+            .do_token()
+            .has_leading_comments(CommentSearch::Single);
+
+    let (end, step) = match (do_on_own_line, step) {
+        (true, Some(step)) => (
+            end,
+            Some(step.update_trailing_trivia(FormatTriviaType::Append(vec![
+                create_newline_trivia(ctx),
+            ]))),
+        ),
+        (true, None) => (
+            end.update_trailing_trivia(FormatTriviaType::Append(vec![create_newline_trivia(ctx)])),
+            None,
+        ),
+        (false, step) => (end, step),
+    };
+
+    let do_token = match do_on_own_line {
+        true => format_end_token(
+            ctx,
+            numeric_for.do_token(),
+            EndTokenType::IndentComments,
+            shape,
+        )
+        .update_leading_trivia(FormatTriviaType::Append(leading_trivia.to_owned())),
+        false => fmt_symbol!(ctx, numeric_for.do_token(), " do", shape),
+    }
+    .update_trailing_trivia(FormatTriviaType::Append(trailing_trivia.to_owned()));
     let block_shape = shape.reset().increment_block_indent();
     let block = format_block(ctx, numeric_for.block(), block_shape);
     let end_token = format_end_token(

tests/inputs/numeric-for-comment-before-do.lua

@@ -0,0 +1,19 @@
+for i = 1, 2 -- comment
+do
+	print(i)
+end
+
+for i = 1, 10, 2 -- comment
+do
+	print(i)
+end
+
+for i = 1, 2
+-- comment
+do
+	print(i)
+end
+
+for i = 1, 2 --[[ comment ]] do
+	print(i)
+end

tests/inputs/parentheses-comment-after-open.lua

@@ -0,0 +1,12 @@
+local a, b, c = true, false, true
+if a
+	and ( -- comment
+		b or c
+	)
+then
+	print("yes")
+end
+
+local x = ( -- comment
+	1 + 2
+)

tests/snapshots/tests__standard@numeric-for-comment-before-do.lua.snap

@@ -0,0 +1,25 @@
+---
+source: tests/tests.rs
+expression: "format(&contents, LuaVersion::Lua51)"
+input_file: tests/inputs/numeric-for-comment-before-do.lua
+---
+for i = 1, 2 -- comment
+do
+	print(i)
+end
+
+for i = 1, 10, 2 -- comment
+do
+	print(i)
+end
+
+for i = 1, 2
+	-- comment
+do
+	print(i)
+end
+
+for i = 1, 2 --[[ comment ]] do
+	print(i)
+end
+

tests/snapshots/tests__standard@parentheses-comment-after-open.lua.snap

@@ -0,0 +1,18 @@
+---
+source: tests/tests.rs
+expression: "format(&contents, LuaVersion::Lua51)"
+input_file: tests/inputs/parentheses-comment-after-open.lua
+---
+local a, b, c = true, false, true
+if
+	a and ( -- comment
+		b or c
+	)
+then
+	print("yes")
+end
+
+local x = ( -- comment
+	1 + 2
+)
+