From 0d526ce5b82c7fd2f2776dffe12b140261f2b9e7 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Fri, 21 Mar 2025 18:59:49 -0700
Subject: [PATCH 01/11] init

---
 .changeset/sharp-rings-march.md                   |  5 +++++
 .../phases/2-analyze/visitors/CallExpression.js   |  9 +++++++++
 .../3-transform/client/visitors/CallExpression.js | 15 +++++++++++++++
 3 files changed, 29 insertions(+)
 create mode 100644 .changeset/sharp-rings-march.md

diff --git a/.changeset/sharp-rings-march.md b/.changeset/sharp-rings-march.md
new file mode 100644
index 000000000000..1fb3ec079656
--- /dev/null
+++ b/.changeset/sharp-rings-march.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+feat: allow `$state` in return statements
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
index 6ef323725b3f..9f713c5d0660 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
@@ -104,6 +104,15 @@ export function CallExpression(node, context) {
 		}
 
 		case '$state':
+			if (
+				(!(parent.type === 'VariableDeclarator' || parent.type === 'ReturnStatement') ||
+					get_parent(context.path, -3).type === 'ConstTag') &&
+				!(parent.type === 'PropertyDefinition' && !parent.static && !parent.computed)
+			) {
+				e.state_invalid_placement(node, rune);
+			}
+
+			break;
 		case '$state.raw':
 		case '$derived':
 		case '$derived.by':
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
index fda43ad7911a..1cd35e2ec0d9 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
@@ -4,6 +4,7 @@ import { dev, is_ignored } from '../../../../state.js';
 import * as b from '../../../../utils/builders.js';
 import { get_rune } from '../../../scope.js';
 import { transform_inspect_rune } from '../../utils.js';
+import { should_proxy } from '../utils.js';
 
 /**
  * @param {CallExpression} node
@@ -33,6 +34,20 @@ export function CallExpression(node, context) {
 		case '$inspect':
 		case '$inspect().with':
 			return transform_inspect_rune(node, context);
+		case '$state':
+			if (context.path.at(-1)?.type === 'ReturnStatement') {
+				if (
+					node.arguments[0] &&
+					should_proxy(
+						/** @type {Expression} */ (context.visit(node.arguments[0])),
+						context.state.scope
+					)
+				) {
+					return b.call('$.proxy', node.arguments[0]);
+				} else {
+					return node.arguments[0] ?? b.void0;
+				}
+			}
 	}
 
 	if (

From 5c3a1534cc524dabc04d4168c800c987d7be092d Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Fri, 21 Mar 2025 19:50:49 -0700
Subject: [PATCH 02/11] oops

---
 .../src/compiler/phases/2-analyze/visitors/CallExpression.js  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
index 2c4928a30d8c..8be793c4a50b 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
@@ -120,6 +120,10 @@ export function CallExpression(node, context) {
 				e.state_invalid_placement(node, rune);
 			}
 
+			if (node.arguments.length > 1) {
+				e.rune_invalid_arguments_length(node, rune, 'zero or one arguments');
+			}
+
 			break;
 		case '$state.raw':
 		case '$derived':

From 7adad75e7f973136cb35afd939d51d538bd6b106 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Sat, 22 Mar 2025 20:20:35 -0700
Subject: [PATCH 03/11] support implicit returns in arrow functions

---
 .../compiler/phases/2-analyze/visitors/CallExpression.js    | 3 ++-
 .../phases/3-transform/client/visitors/CallExpression.js    | 6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
index 8be793c4a50b..995b1d79f831 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/CallExpression.js
@@ -115,7 +115,8 @@ export function CallExpression(node, context) {
 			if (
 				(!(parent.type === 'VariableDeclarator' || parent.type === 'ReturnStatement') ||
 					get_parent(context.path, -3).type === 'ConstTag') &&
-				!(parent.type === 'PropertyDefinition' && !parent.static && !parent.computed)
+				!(parent.type === 'PropertyDefinition' && !parent.static && !parent.computed) &&
+				!(parent.type === 'ArrowFunctionExpression' && parent.body === node)
 			) {
 				e.state_invalid_placement(node, rune);
 			}
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
index 1cd35e2ec0d9..aa718b9988a8 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
@@ -11,6 +11,7 @@ import { should_proxy } from '../utils.js';
  * @param {Context} context
  */
 export function CallExpression(node, context) {
+	const parent = context.path.at(-1);
 	switch (get_rune(node, context.state.scope)) {
 		case '$host':
 			return b.id('$$props.$$host');
@@ -35,7 +36,10 @@ export function CallExpression(node, context) {
 		case '$inspect().with':
 			return transform_inspect_rune(node, context);
 		case '$state':
-			if (context.path.at(-1)?.type === 'ReturnStatement') {
+			if (
+				parent?.type === 'ReturnStatement' ||
+				(parent?.type === 'ArrowFunctionExpression' && parent.body === node)
+			) {
 				if (
 					node.arguments[0] &&
 					should_proxy(

From 4d11b5656e0aeec3c5964c290193908e2afdd8ca Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Fri, 28 Mar 2025 19:43:09 -0700
Subject: [PATCH 04/11] add tests, add to server

---
 .../3-transform/server/visitors/CallExpression.js  | 14 +++++++++++++-
 .../_expected/client/index.svelte.js               | 14 ++++++++++++++
 .../_expected/server/index.svelte.js               | 14 ++++++++++++++
 .../samples/state-in-return/index.svelte.js        |  8 ++++++++
 4 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/state-in-return/_expected/server/index.svelte.js
 create mode 100644 packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js

diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js
index a425bc5ec430..ad573b03295b 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/CallExpression.js
@@ -1,4 +1,4 @@
-/** @import { CallExpression, Expression } from 'estree' */
+/** @import { ArrowFunctionExpression, CallExpression, Expression } from 'estree' */
 /** @import { Context } from '../types.js' */
 import { is_ignored } from '../../../../state.js';
 import * as b from '../../../../utils/builders.js';
@@ -37,5 +37,17 @@ export function CallExpression(node, context) {
 		return transform_inspect_rune(node, context);
 	}
 
+	if (
+		rune === '$state' &&
+		(context.path.at(-1)?.type === 'ReturnStatement' ||
+			(context.path.at(-1)?.type === 'ArrowFunctionExpression' &&
+				/** @type {ArrowFunctionExpression} */ (context.path.at(-1)).body === node))
+	) {
+		if (node.arguments[0]) {
+			return context.visit(node.arguments[0]);
+		}
+		return b.void0;
+	}
+
 	context.next();
 }
diff --git a/packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js
new file mode 100644
index 000000000000..55f38f174e19
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js
@@ -0,0 +1,14 @@
+/* index.svelte.js generated by Svelte VERSION */
+import * as $ from 'svelte/internal/client';
+
+export default function proxy(object) {
+	return $.proxy(object);
+}
+
+export function createCounter() {
+	let count = $.state(0);
+
+	$.update(count);
+}
+
+export const proxy_in_arrow = (object) => $.proxy(object);
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/state-in-return/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/state-in-return/_expected/server/index.svelte.js
new file mode 100644
index 000000000000..de52cde883be
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/state-in-return/_expected/server/index.svelte.js
@@ -0,0 +1,14 @@
+/* index.svelte.js generated by Svelte VERSION */
+import * as $ from 'svelte/internal/server';
+
+export default function proxy(object) {
+	return object;
+}
+
+export function createCounter() {
+	let count = 0;
+
+	count++;
+}
+
+export const proxy_in_arrow = (object) => object;
\ No newline at end of file
diff --git a/packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js b/packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js
new file mode 100644
index 000000000000..f30cdd0408b9
--- /dev/null
+++ b/packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js
@@ -0,0 +1,8 @@
+export default function proxy(object) {
+    return $state(object);
+}
+export function createCounter() {
+    let count = $state(0);
+    count++;
+}
+export const proxy_in_arrow = object => $state(object);
\ No newline at end of file

From e13c7d9b22c89e598dabcece31f2dd480520f7c8 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Fri, 28 Mar 2025 19:46:47 -0700
Subject: [PATCH 05/11] lint

---
 .../snapshot/samples/state-in-return/index.svelte.js      | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js b/packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js
index f30cdd0408b9..66d143f4096e 100644
--- a/packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/state-in-return/index.svelte.js
@@ -1,8 +1,8 @@
 export default function proxy(object) {
-    return $state(object);
+	return $state(object);
 }
 export function createCounter() {
-    let count = $state(0);
-    count++;
+	let count = $state(0);
+	count++;
 }
-export const proxy_in_arrow = object => $state(object);
\ No newline at end of file
+export const proxy_in_arrow = (object) => $state(object);

From 8f715843a35a2a372fe15fbff6349a3f0f0c61eb Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Tue, 8 Apr 2025 15:13:05 -0700
Subject: [PATCH 06/11] tweak changeset

---
 .changeset/sharp-rings-march.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.changeset/sharp-rings-march.md b/.changeset/sharp-rings-march.md
index 1fb3ec079656..bd3a5e531210 100644
--- a/.changeset/sharp-rings-march.md
+++ b/.changeset/sharp-rings-march.md
@@ -1,5 +1,5 @@
 ---
-'svelte': patch
+'svelte': minor
 ---
 
 feat: allow `$state` in return statements

From 967ccc5d86a71f319f265d725d7eee327352b810 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Tue, 29 Apr 2025 17:08:20 -0700
Subject: [PATCH 07/11] add warning in dev, add docs

---
 documentation/docs/02-runes/02-$state.md         | 13 +++++++++++++
 .../98-reference/.generated/client-warnings.md   |  6 ++++++
 .../svelte/messages/client-warnings/warnings.md  |  4 ++++
 .../client/visitors/CallExpression.js            | 15 +++++----------
 packages/svelte/src/internal/client/proxy.js     | 16 ++++++++++++++++
 packages/svelte/src/internal/client/warnings.js  | 11 +++++++++++
 .../_expected/client/index.svelte.js             |  4 ++--
 7 files changed, 57 insertions(+), 12 deletions(-)

diff --git a/documentation/docs/02-runes/02-$state.md b/documentation/docs/02-runes/02-$state.md
index 16630a977b62..e98c66f08ffb 100644
--- a/documentation/docs/02-runes/02-$state.md
+++ b/documentation/docs/02-runes/02-$state.md
@@ -65,6 +65,19 @@ let { done, text } = todos[0];
 todos[0].done = !todos[0].done;
 ```
 
+You can also use `$state` in return statements to proxy their argument:
+
+```js
+function createCounter() {
+	return $state({
+		count: 0,
+		increment() {
+			this.count++;
+		}
+	});
+}
+```
+
 ### Classes
 
 You can also use `$state` in class fields (whether public or private):
diff --git a/documentation/docs/98-reference/.generated/client-warnings.md b/documentation/docs/98-reference/.generated/client-warnings.md
index 77d1df4cdde2..92b25f806c85 100644
--- a/documentation/docs/98-reference/.generated/client-warnings.md
+++ b/documentation/docs/98-reference/.generated/client-warnings.md
@@ -219,6 +219,12 @@ Reactive `$state(...)` proxies and the values they proxy have different identiti
 
 To resolve this, ensure you're comparing values where both values were created with `$state(...)`, or neither were. Note that `$state.raw(...)` will _not_ create a state proxy.
 
+### state_return_not_proxyable
+
+```
+The argument passed to a `$state` in a return statement must be a plain object or array. Otherwise, the `$state` call will have no effect
+```
+
 ### transition_slide_display
 
 ```
diff --git a/packages/svelte/messages/client-warnings/warnings.md b/packages/svelte/messages/client-warnings/warnings.md
index f8e9ebd8a047..7c644409ce43 100644
--- a/packages/svelte/messages/client-warnings/warnings.md
+++ b/packages/svelte/messages/client-warnings/warnings.md
@@ -185,6 +185,10 @@ To fix it, either create callback props to communicate changes, or mark `person`
 
 To resolve this, ensure you're comparing values where both values were created with `$state(...)`, or neither were. Note that `$state.raw(...)` will _not_ create a state proxy.
 
+## state_return_not_proxyable
+
+> The argument passed to a `$state` call in a return statement must be a plain object or array. Otherwise, the `$state` call will have no effect
+
 ## transition_slide_display
 
 > The `slide` transition does not work correctly for elements with `display: %value%`
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
index b381f56504ef..5e16a5055060 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/CallExpression.js
@@ -40,16 +40,11 @@ export function CallExpression(node, context) {
 				parent?.type === 'ReturnStatement' ||
 				(parent?.type === 'ArrowFunctionExpression' && parent.body === node)
 			) {
-				if (
-					node.arguments[0] &&
-					should_proxy(
-						/** @type {Expression} */ (context.visit(node.arguments[0])),
-						context.state.scope
-					)
-				) {
-					return b.call('$.proxy', node.arguments[0]);
-				} else {
-					return node.arguments[0] ?? b.void0;
+				if (node.arguments[0]) {
+					return b.call(
+						'$.return_proxy',
+						/** @type {Expression} */ (context.visit(node.arguments[0] ?? b.void0))
+					);
 				}
 			}
 	}
diff --git a/packages/svelte/src/internal/client/proxy.js b/packages/svelte/src/internal/client/proxy.js
index fd5706eaf270..515531e87671 100644
--- a/packages/svelte/src/internal/client/proxy.js
+++ b/packages/svelte/src/internal/client/proxy.js
@@ -12,6 +12,7 @@ import { state as source, set } from './reactivity/sources.js';
 import { STATE_SYMBOL } from '#client/constants';
 import { UNINITIALIZED } from '../../constants.js';
 import * as e from './errors.js';
+import * as w from './warnings.js';
 import { get_stack } from './dev/tracing.js';
 import { tracing_mode_flag } from '../flags/index.js';
 
@@ -282,6 +283,21 @@ export function proxy(value) {
 	});
 }
 
+/**
+ * @template T
+ * @param {T} value
+ * @param {Source<T>} [prev]
+ * @returns {T | void}
+ */
+export function return_proxy(value, prev) {
+	const res = proxy(value, prev);
+	if (res !== value || (typeof value === 'object' && value !== null && STATE_SYMBOL in value)) {
+		// if the argument passed was already a proxy, we don't warn
+		return res;
+	}
+	w.state_return_not_proxyable();
+}
+
 /**
  * @param {Source<number>} signal
  * @param {1 | -1} [d]
diff --git a/packages/svelte/src/internal/client/warnings.js b/packages/svelte/src/internal/client/warnings.js
index c84b487e280d..5d41c201b43f 100644
--- a/packages/svelte/src/internal/client/warnings.js
+++ b/packages/svelte/src/internal/client/warnings.js
@@ -170,6 +170,17 @@ export function state_proxy_equality_mismatch(operator) {
 	}
 }
 
+/**
+ * The argument passed to a `$state` in a return statement must be a plain object or array. Otherwise, the `$state` call will have no effect
+ */
+export function state_return_not_proxyable() {
+	if (DEV) {
+		console.warn(`%c[svelte] state_return_not_proxyable\n%cThe argument passed to a \`$state\` in a return statement must be a plain object or array. Otherwise, the \`$state\` call will have no effect\nhttps://svelte.dev/e/state_return_not_proxyable`, bold, normal);
+	} else {
+		console.warn(`https://svelte.dev/e/state_return_not_proxyable`);
+	}
+}
+
 /**
  * The `slide` transition does not work correctly for elements with `display: %value%`
  * @param {string} value
diff --git a/packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js b/packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js
index 55f38f174e19..de55e87b536a 100644
--- a/packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/state-in-return/_expected/client/index.svelte.js
@@ -2,7 +2,7 @@
 import * as $ from 'svelte/internal/client';
 
 export default function proxy(object) {
-	return $.proxy(object);
+	return $.return_proxy(object);
 }
 
 export function createCounter() {
@@ -11,4 +11,4 @@ export function createCounter() {
 	$.update(count);
 }
 
-export const proxy_in_arrow = (object) => $.proxy(object);
\ No newline at end of file
+export const proxy_in_arrow = (object) => $.return_proxy(object);
\ No newline at end of file

From d28fe7e1520aea39fab7125f9524fa3ccd196e3a Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Tue, 29 Apr 2025 17:11:03 -0700
Subject: [PATCH 08/11] doh

---
 packages/svelte/src/internal/client/index.js | 2 +-
 packages/svelte/src/internal/client/proxy.js | 5 ++---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 14d6e29f5bb4..eb5321c9409e 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -141,7 +141,7 @@ export {
 } from './runtime.js';
 export { validate_binding, validate_each_keys } from './validate.js';
 export { raf } from './timing.js';
-export { proxy } from './proxy.js';
+export { proxy, return_proxy } from './proxy.js';
 export { create_custom_element } from './dom/elements/custom-element.js';
 export {
 	child,
diff --git a/packages/svelte/src/internal/client/proxy.js b/packages/svelte/src/internal/client/proxy.js
index 515531e87671..51692f3ce947 100644
--- a/packages/svelte/src/internal/client/proxy.js
+++ b/packages/svelte/src/internal/client/proxy.js
@@ -286,11 +286,10 @@ export function proxy(value) {
 /**
  * @template T
  * @param {T} value
- * @param {Source<T>} [prev]
  * @returns {T | void}
  */
-export function return_proxy(value, prev) {
-	const res = proxy(value, prev);
+export function return_proxy(value) {
+	const res = proxy(value);
 	if (res !== value || (typeof value === 'object' && value !== null && STATE_SYMBOL in value)) {
 		// if the argument passed was already a proxy, we don't warn
 		return res;

From 8ebcd913ec831562d2d343eeaf3c4ed84a66c7d7 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Tue, 29 Apr 2025 17:17:57 -0700
Subject: [PATCH 09/11] rewrite logic

---
 packages/svelte/src/internal/client/proxy.js | 31 +++++++++++++-------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/packages/svelte/src/internal/client/proxy.js b/packages/svelte/src/internal/client/proxy.js
index 51692f3ce947..f9afaef3aa98 100644
--- a/packages/svelte/src/internal/client/proxy.js
+++ b/packages/svelte/src/internal/client/proxy.js
@@ -16,6 +16,21 @@ import * as w from './warnings.js';
 import { get_stack } from './dev/tracing.js';
 import { tracing_mode_flag } from '../flags/index.js';
 
+/**
+ * @param {unknown} value
+ * @returns {boolean}
+ */
+function should_proxy(value) {
+	if (typeof value !== 'object' || value === null || STATE_SYMBOL in value) {
+		return false;
+	}
+	const prototype = get_prototype_of(value);
+	if (prototype !== object_prototype && prototype !== array_prototype) {
+		return false;
+	}
+	return true;
+}
+
 /**
  * @template T
  * @param {T} value
@@ -23,13 +38,7 @@ import { tracing_mode_flag } from '../flags/index.js';
  */
 export function proxy(value) {
 	// if non-proxyable, or is already a proxy, return `value`
-	if (typeof value !== 'object' || value === null || STATE_SYMBOL in value) {
-		return value;
-	}
-
-	const prototype = get_prototype_of(value);
-
-	if (prototype !== object_prototype && prototype !== array_prototype) {
+	if (!should_proxy(value)) {
 		return value;
 	}
 
@@ -289,10 +298,12 @@ export function proxy(value) {
  * @returns {T | void}
  */
 export function return_proxy(value) {
-	const res = proxy(value);
-	if (res !== value || (typeof value === 'object' && value !== null && STATE_SYMBOL in value)) {
+	if (
+		!should_proxy(value) &&
+		!(typeof value === 'object' && value !== null && STATE_SYMBOL in value)
+	) {
 		// if the argument passed was already a proxy, we don't warn
-		return res;
+		return proxy(value);
 	}
 	w.state_return_not_proxyable();
 }

From b64fb09028a9d35b089b80522278fce93f9c4266 Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Tue, 29 Apr 2025 17:23:09 -0700
Subject: [PATCH 10/11] `node scripts/process-messages`

---
 documentation/docs/98-reference/.generated/client-warnings.md | 2 +-
 packages/svelte/src/internal/client/warnings.js               | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/documentation/docs/98-reference/.generated/client-warnings.md b/documentation/docs/98-reference/.generated/client-warnings.md
index 92b25f806c85..7bfc20e58905 100644
--- a/documentation/docs/98-reference/.generated/client-warnings.md
+++ b/documentation/docs/98-reference/.generated/client-warnings.md
@@ -222,7 +222,7 @@ To resolve this, ensure you're comparing values where both values were created w
 ### state_return_not_proxyable
 
 ```
-The argument passed to a `$state` in a return statement must be a plain object or array. Otherwise, the `$state` call will have no effect
+The argument passed to a `$state` call in a return statement must be a plain object or array. Otherwise, the `$state` call will have no effect
 ```
 
 ### transition_slide_display
diff --git a/packages/svelte/src/internal/client/warnings.js b/packages/svelte/src/internal/client/warnings.js
index 5d41c201b43f..acb9f82c0cb6 100644
--- a/packages/svelte/src/internal/client/warnings.js
+++ b/packages/svelte/src/internal/client/warnings.js
@@ -171,11 +171,11 @@ export function state_proxy_equality_mismatch(operator) {
 }
 
 /**
- * The argument passed to a `$state` in a return statement must be a plain object or array. Otherwise, the `$state` call will have no effect
+ * The argument passed to a `$state` call in a return statement must be a plain object or array. Otherwise, the `$state` call will have no effect
  */
 export function state_return_not_proxyable() {
 	if (DEV) {
-		console.warn(`%c[svelte] state_return_not_proxyable\n%cThe argument passed to a \`$state\` in a return statement must be a plain object or array. Otherwise, the \`$state\` call will have no effect\nhttps://svelte.dev/e/state_return_not_proxyable`, bold, normal);
+		console.warn(`%c[svelte] state_return_not_proxyable\n%cThe argument passed to a \`$state\` call in a return statement must be a plain object or array. Otherwise, the \`$state\` call will have no effect\nhttps://svelte.dev/e/state_return_not_proxyable`, bold, normal);
 	} else {
 		console.warn(`https://svelte.dev/e/state_return_not_proxyable`);
 	}

From 5193f2c28922ce56ff89a73910fea22e269fad4f Mon Sep 17 00:00:00 2001
From: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Date: Sun, 4 May 2025 12:37:26 -0700
Subject: [PATCH 11/11] fix, only warn in dev

---
 packages/svelte/src/internal/client/proxy.js | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/packages/svelte/src/internal/client/proxy.js b/packages/svelte/src/internal/client/proxy.js
index f9afaef3aa98..9499e7f9ddb9 100644
--- a/packages/svelte/src/internal/client/proxy.js
+++ b/packages/svelte/src/internal/client/proxy.js
@@ -298,14 +298,13 @@ export function proxy(value) {
  * @returns {T | void}
  */
 export function return_proxy(value) {
-	if (
-		!should_proxy(value) &&
-		!(typeof value === 'object' && value !== null && STATE_SYMBOL in value)
-	) {
-		// if the argument passed was already a proxy, we don't warn
+	if (should_proxy(value)) {
 		return proxy(value);
+	} else if (DEV && !(typeof value === 'object' && value !== null && STATE_SYMBOL in value)) {
+		// if the argument passed was already a proxy, we don't warn
+		w.state_return_not_proxyable();
 	}
-	w.state_return_not_proxyable();
+	return value;
 }
 
 /**