ast, parser, fmt: fix formatting return with comments in parentheses (#19188)

vlib/v/ast/ast.v

@@ -1380,7 +1380,8 @@ pub struct ParExpr {
 pub:
 	pos token.Pos
 pub mut:
-	expr Expr
+	expr     Expr
+	comments []Comment
 }
 
 [minify]

vlib/v/fmt/fmt.v

@@ -1393,7 +1393,7 @@ pub fn (mut f Fmt) return_stmt(node ast.Return) {
 				f.comments(pre_comments)
 				f.write(' ')
 			}
-			if expr is ast.ParExpr {
+			if expr is ast.ParExpr && expr.comments.len == 0 {
 				f.expr(expr.expr)
 			} else {
 				f.expr(expr)
@@ -2698,12 +2698,22 @@ pub fn (mut f Fmt) par_expr(node ast.ParExpr) {
 	for mut expr is ast.ParExpr {
 		expr = expr.expr
 	}
-	requires_paren := expr !is ast.Ident
+	requires_paren := expr !is ast.Ident || node.comments.len > 0
 	if requires_paren {
 		f.par_level++
 		f.write('(')
 	}
+	pre_comments := node.comments.filter(it.pos.pos < expr.pos().pos)
+	post_comments := node.comments[pre_comments.len..]
+	if pre_comments.len > 0 {
+		f.comments(pre_comments)
+		f.write(' ')
+	}
 	f.expr(expr)
+	if post_comments.len > 0 {
+		f.comments(post_comments)
+		f.write(' ')
+	}
 	if requires_paren {
 		f.par_level--
 		f.write(')')

vlib/v/fmt/tests/return_with_comments_expected.vv

@@ -0,0 +1,22 @@
+fn foo1() int {
+	return (0 /* some comment */ )
+}
+
+fn foo2() int {
+	return ( /* some comment */ 0)
+}
+
+fn foo3() int {
+	return ( /* some comment1 */ 0 /* some comment2 */ )
+}
+
+fn foo4() int {
+	return ( /* some comment1 */ /* some comment2 */ 0)
+}
+
+fn foo5() int {
+	return ( /* some comment1 */ /* some comment2 */ 0 /* some comment3 */ /* some comment4 */ )
+}
+
+fn main() {
+}

vlib/v/fmt/tests/return_with_comments_input.vv

@@ -0,0 +1,22 @@
+fn foo1() int {
+    return (0/* some comment */)
+}
+
+fn foo2() int {
+    return (/* some comment */0)
+}
+
+fn foo3() int {
+    return (/* some comment1 */ 0/* some comment2 */)
+}
+
+fn foo4() int {
+    return (/* some comment1 */ /* some comment2 */0)
+}
+
+fn foo5() int {
+    return (/* some comment1 */ /* some comment2 */0/* some comment3 */ /* some comment4 */)
+}
+
+fn main() {
+}

vlib/v/parser/expr.v

@@ -147,11 +147,14 @@ fn (mut p Parser) check_expr(precedence int) !ast.Expr {
 		.lpar {
 			mut pos := p.tok.pos()
 			p.check(.lpar)
+			mut comments := p.eat_comments()
 			node = p.expr(0)
+			comments << p.eat_comments()
 			p.check(.rpar)
 			node = ast.ParExpr{
 				expr: node
 				pos: pos.extend(p.prev_tok.pos())
+				comments: comments
 			}
 		}
 		.key_if {