From 8197537c9ac7b950b75d27b103cc4766ea31f61e Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 19 Mar 2025 22:53:22 -0400
Subject: [PATCH] no need to push_derived_source with mutable_state, as it
 never coexists with $.derived

---
 .../phases/3-transform/client/transform-client.js      |  5 ++++-
 .../3-transform/client/visitors/VariableDeclaration.js |  4 ++--
 packages/svelte/src/internal/client/index.js           |  2 +-
 .../svelte/src/internal/client/reactivity/sources.js   | 10 ----------
 4 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
index ac8263b916..0bdfbae746 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/transform-client.js
@@ -219,7 +219,10 @@ export function client_component(analysis, options) {
 	for (const [name, binding] of analysis.instance.scope.declarations) {
 		if (binding.kind === 'legacy_reactive') {
 			legacy_reactive_declarations.push(
-				b.const(name, b.call('$.mutable_state', undefined, analysis.immutable ? b.true : undefined))
+				b.const(
+					name,
+					b.call('$.mutable_source', undefined, analysis.immutable ? b.true : undefined)
+				)
 			);
 		}
 		if (binding.kind === 'store_sub') {
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
index baffc5dec3..3a914fb560 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/VariableDeclaration.js
@@ -299,7 +299,7 @@ function create_state_declarators(declarator, { scope, analysis }, value) {
 		return [
 			b.declarator(
 				declarator.id,
-				b.call('$.mutable_state', value, analysis.immutable ? b.true : undefined)
+				b.call('$.mutable_source', value, analysis.immutable ? b.true : undefined)
 			)
 		];
 	}
@@ -314,7 +314,7 @@ function create_state_declarators(declarator, { scope, analysis }, value) {
 			return b.declarator(
 				path.node,
 				binding?.kind === 'state'
-					? b.call('$.mutable_state', value, analysis.immutable ? b.true : undefined)
+					? b.call('$.mutable_source', value, analysis.immutable ? b.true : undefined)
 					: value
 			);
 		})
diff --git a/packages/svelte/src/internal/client/index.js b/packages/svelte/src/internal/client/index.js
index 31da00dbb4..6b74a16ec8 100644
--- a/packages/svelte/src/internal/client/index.js
+++ b/packages/svelte/src/internal/client/index.js
@@ -113,7 +113,7 @@ export {
 	user_effect,
 	user_pre_effect
 } from './reactivity/effects.js';
-export { mutable_state, mutate, set, state, update, update_pre } from './reactivity/sources.js';
+export { mutable_source, mutate, set, state, update, update_pre } from './reactivity/sources.js';
 export {
 	prop,
 	rest_props,
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 93bb77126a..e99e83b343 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -101,16 +101,6 @@ export function mutable_source(initial_value, immutable = false) {
 	return s;
 }
 
-/**
- * @template V
- * @param {V} v
- * @param {boolean} [immutable]
- * @returns {Source<V>}
- */
-export function mutable_state(v, immutable = false) {
-	return push_derived_source(mutable_source(v, immutable));
-}
-
 /**
  * @template V
  * @param {Source<V>} source