From 17eb1d83ca57ccbb921ef105007c9b28eef8e12f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EA=B0=95=EB=8F=99=EC=9C=A4=20=28Donny=29?=
 <kdy1997.dev@gmail.com>
Date: Tue, 20 Feb 2024 10:17:03 +0900
Subject: [PATCH 1/2] Highlight only directive line

---
 .../src/transforms/server_actions.rs                      | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/next-swc/crates/next-custom-transforms/src/transforms/server_actions.rs b/packages/next-swc/crates/next-custom-transforms/src/transforms/server_actions.rs
index 79badb09d7216..3651b56b7a87b 100644
--- a/packages/next-swc/crates/next-custom-transforms/src/transforms/server_actions.rs
+++ b/packages/next-swc/crates/next-custom-transforms/src/transforms/server_actions.rs
@@ -6,6 +6,7 @@ use std::{
 use hex::encode as hex_encode;
 use serde::Deserialize;
 use sha1::{Digest, Sha1};
+use swc_core::common::Span;
 use turbopack_binding::swc::core::{
     common::{
         comments::{Comment, CommentKind, Comments},
@@ -125,10 +126,12 @@ impl<C: Comments> ServerActions<C> {
         } else {
             // Check if the function has `"use server"`
             if let Some(body) = maybe_body {
+                let mut action_span = None;
                 remove_server_directive_index_in_fn(
                     &mut body.stmts,
                     remove_directive,
                     &mut is_action_fn,
+                    &mut action_span,
                     self.config.enabled,
                 );
 
@@ -136,7 +139,7 @@ impl<C: Comments> ServerActions<C> {
                     HANDLER.with(|handler| {
                         handler
                             .struct_span_err(
-                                body.span,
+                                action_span.unwrap_or(body.span),
                                 "It is not allowed to define inline \"use server\" annotated Server Actions in Client Components.\nTo use Server Actions in a Client Component, you can either export them from a separate file with \"use server\" at the top, or pass them down through props from a Server Component.\n\nRead more: https://nextjs.org/docs/app/api-reference/functions/server-actions#with-client-components\n",
                             )
                             .emit()
@@ -1396,6 +1399,7 @@ fn remove_server_directive_index_in_fn(
     stmts: &mut Vec<Stmt>,
     remove_directive: bool,
     is_action_fn: &mut bool,
+    action_span: &mut Option<Span>,
     enabled: bool,
 ) {
     let mut is_directive = true;
@@ -1407,6 +1411,8 @@ fn remove_server_directive_index_in_fn(
         }) = stmt
         {
             if value == "use server" {
+                *action_span = Some(*span);
+
                 if is_directive {
                     *is_action_fn = true;
                     if !enabled {

From 5f60a7c3fa147b10694aab96c1b9ab1c1e9b0df5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EA=B0=95=EB=8F=99=EC=9C=A4=20=28Donny=29?=
 <kdy1997.dev@gmail.com>
Date: Tue, 20 Feb 2024 11:04:52 +0900
Subject: [PATCH 2/2] Update test refs

---
 .../server-actions/client-graph/1/output.stderr       | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/packages/next-swc/crates/next-custom-transforms/tests/errors/server-actions/client-graph/1/output.stderr b/packages/next-swc/crates/next-custom-transforms/tests/errors/server-actions/client-graph/1/output.stderr
index 9f20dd6734675..25657d291a76d 100644
--- a/packages/next-swc/crates/next-custom-transforms/tests/errors/server-actions/client-graph/1/output.stderr
+++ b/packages/next-swc/crates/next-custom-transforms/tests/errors/server-actions/client-graph/1/output.stderr
@@ -4,10 +4,9 @@
   | 
   | Read more: https://nextjs.org/docs/app/api-reference/functions/server-actions#with-client-components
   | 
-   ,-[input.js:3:1]
- 3 |     export default function App() {
- 4 | ,->   async function fn() {
- 5 | |       'use server'
- 6 | `->   }
- 7 |       return <div>App</div>
+   ,-[input.js:4:1]
+ 4 |   async function fn() {
+ 5 |     'use server'
+   :     ^^^^^^^^^^^^
+ 6 |   }
    `----