From 2ba45da40b0bb0edfc709f84810e5e5a5adc6ab0 Mon Sep 17 00:00:00 2001
From: paoloricciuti <ricciutipaolo@gmail.com>
Date: Mon, 20 May 2024 22:22:36 +0200
Subject: [PATCH] fix: migrate derivations without semicolons

---
 .changeset/kind-snakes-drive.md                    |  5 +++++
 packages/svelte/src/compiler/migrate/index.js      | 14 +++++++++-----
 .../samples/derivations-no-colon/input.svelte      |  7 +++++++
 .../samples/derivations-no-colon/output.svelte     |  7 +++++++
 4 files changed, 28 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/kind-snakes-drive.md
 create mode 100644 packages/svelte/tests/migrate/samples/derivations-no-colon/input.svelte
 create mode 100644 packages/svelte/tests/migrate/samples/derivations-no-colon/output.svelte

diff --git a/.changeset/kind-snakes-drive.md b/.changeset/kind-snakes-drive.md
new file mode 100644
index 000000000000..4ca726ad9a67
--- /dev/null
+++ b/.changeset/kind-snakes-drive.md
@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: migrate derivations without semicolons
diff --git a/packages/svelte/src/compiler/migrate/index.js b/packages/svelte/src/compiler/migrate/index.js
index 0a64088c5a9e..0ca0fba137b3 100644
--- a/packages/svelte/src/compiler/migrate/index.js
+++ b/packages/svelte/src/compiler/migrate/index.js
@@ -369,11 +369,15 @@ const instance_script = {
 					/** @type {number} */ (node.body.expression.right.start),
 					'$derived('
 				);
-				state.str.update(
-					/** @type {number} */ (node.body.expression.right.end),
-					/** @type {number} */ (node.end),
-					');'
-				);
+				if (node.body.expression.right.end !== node.end) {
+					state.str.update(
+						/** @type {number} */ (node.body.expression.right.end),
+						/** @type {number} */ (node.end),
+						');'
+					);
+				} else {
+					state.str.appendRight(/** @type {number} */ (node.end), ');');
+				}
 				return;
 			} else {
 				for (const binding of reassigned_bindings) {
diff --git a/packages/svelte/tests/migrate/samples/derivations-no-colon/input.svelte b/packages/svelte/tests/migrate/samples/derivations-no-colon/input.svelte
new file mode 100644
index 000000000000..7df9187a0283
--- /dev/null
+++ b/packages/svelte/tests/migrate/samples/derivations-no-colon/input.svelte
@@ -0,0 +1,7 @@
+<script>
+	let count = 0;
+	$: doubled = count * 2
+	$: ({ quadrupled } = { quadrupled: count * 4 })
+</script>
+
+{count} / {doubled} / {quadrupled}
diff --git a/packages/svelte/tests/migrate/samples/derivations-no-colon/output.svelte b/packages/svelte/tests/migrate/samples/derivations-no-colon/output.svelte
new file mode 100644
index 000000000000..f6af6dd45069
--- /dev/null
+++ b/packages/svelte/tests/migrate/samples/derivations-no-colon/output.svelte
@@ -0,0 +1,7 @@
+<script>
+	let count = 0;
+	let doubled = $derived(count * 2);
+	let { quadrupled } = $derived({ quadrupled: count * 4 });
+</script>
+
+{count} / {doubled} / {quadrupled}
\ No newline at end of file