From f5775b7fce9736c6857f199eb01a3718d83a3586 Mon Sep 17 00:00:00 2001
From: Bob Fanger <bob@thisisdevelopment.nl>
Date: Sat, 22 Jun 2024 19:45:15 +0200
Subject: [PATCH 1/2] feat: signal-prefer-let rule

---
 .changeset/proud-donuts-tickle.md             |  5 ++
 README.md                                     |  1 +
 docs/rules.md                                 |  1 +
 docs/rules/signal-prefer-let.md               | 50 ++++++++++++++++++
 .../eslint-plugin-svelte/src/rule-types.ts    |  5 ++
 .../src/rules/signal-prefer-let.ts            | 51 +++++++++++++++++++
 .../eslint-plugin-svelte/src/utils/rules.ts   |  2 +
 .../invalid/test01-errors.yaml                | 12 +++++
 .../invalid/test01-input.svelte               |  6 +++
 .../invalid/test01-output.svelte              |  6 +++
 .../valid/test01-input.svelte                 |  3 ++
 .../tests/src/rules/signal-prefer-let.ts      | 12 +++++
 12 files changed, 154 insertions(+)
 create mode 100644 .changeset/proud-donuts-tickle.md
 create mode 100644 docs/rules/signal-prefer-let.md
 create mode 100644 packages/eslint-plugin-svelte/src/rules/signal-prefer-let.ts
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-input.svelte
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-output.svelte
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte
 create mode 100644 packages/eslint-plugin-svelte/tests/src/rules/signal-prefer-let.ts

diff --git a/.changeset/proud-donuts-tickle.md b/.changeset/proud-donuts-tickle.md
new file mode 100644
index 000000000..a528563c8
--- /dev/null
+++ b/.changeset/proud-donuts-tickle.md
@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': minor
+---
+
+New svelte/signal-prefer-let rule
diff --git a/README.md b/README.md
index 9a6c25600..858bc4e52 100644
--- a/README.md
+++ b/README.md
@@ -430,6 +430,7 @@ These rules relate to better ways of doing things to help you avoid problems:
 | [svelte/require-event-dispatcher-types](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-event-dispatcher-types/) | require type parameters for `createEventDispatcher` |  |
 | [svelte/require-optimized-style-attribute](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-optimized-style-attribute/) | require style attributes that can be optimized |  |
 | [svelte/require-stores-init](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-stores-init/) | require initial value in store |  |
+| [svelte/signal-prefer-let](https://sveltejs.github.io/eslint-plugin-svelte/rules/signal-prefer-let/) | use let instead of const for signals values | :wrench: |
 | [svelte/valid-each-key](https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-each-key/) | enforce keys to use variables defined in the `{#each}` block |  |
 
 ## Stylistic Issues
diff --git a/docs/rules.md b/docs/rules.md
index 7f115da5c..d89287762 100644
--- a/docs/rules.md
+++ b/docs/rules.md
@@ -67,6 +67,7 @@ These rules relate to better ways of doing things to help you avoid problems:
 | [svelte/require-event-dispatcher-types](./rules/require-event-dispatcher-types.md)       | require type parameters for `createEventDispatcher`                                                                                       |          |
 | [svelte/require-optimized-style-attribute](./rules/require-optimized-style-attribute.md) | require style attributes that can be optimized                                                                                            |          |
 | [svelte/require-stores-init](./rules/require-stores-init.md)                             | require initial value in store                                                                                                            |          |
+| [svelte/signal-prefer-let](./rules/signal-prefer-let.md)                                 | use let instead of const for signals values                                                                                               | :wrench: |
 | [svelte/valid-each-key](./rules/valid-each-key.md)                                       | enforce keys to use variables defined in the `{#each}` block                                                                              |          |
 
 ## Stylistic Issues
diff --git a/docs/rules/signal-prefer-let.md b/docs/rules/signal-prefer-let.md
new file mode 100644
index 000000000..44f59a527
--- /dev/null
+++ b/docs/rules/signal-prefer-let.md
@@ -0,0 +1,50 @@
+---
+pageClass: 'rule-details'
+sidebarDepth: 0
+title: 'svelte/signal-prefer-let'
+description: 'use let instead of const for signals values'
+---
+
+# svelte/signal-prefer-let
+
+> use let instead of const for signals values
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> **_This rule has not been released yet._** </badge>
+- :wrench: The `--fix` option on the [command line](https://eslint.org/docs/user-guide/command-line-interface#fixing-problems) can automatically fix some of the problems reported by this rule.
+
+## :book: Rule Details
+
+This rule reports whenever a signal is assigned to a const.
+In JavaScript `const` are defined as immutable references which cannot be reassigned.
+Signals are by definition changing and are reassigned by Svelte's reactivity system.
+
+<ESLintCodeBlock fix>
+
+<!--eslint-skip-->
+
+```svelte
+<script>
+  /* eslint svelte/signal-prefer-let: "error" */
+
+  /* ✓ GOOD */
+  let { value } = $props();
+
+  let doubled = $derived(value * 2);
+
+  /* ✗ BAD */
+  const { value } = $props();
+
+  const doubled = $derived(value * 2);
+</script>
+```
+
+</ESLintCodeBlock>
+
+## :wrench: Options
+
+Nothing
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/src/rules/signal-prefer-let.ts)
+- [Test source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/tests/src/rules/signal-prefer-let.ts)
diff --git a/packages/eslint-plugin-svelte/src/rule-types.ts b/packages/eslint-plugin-svelte/src/rule-types.ts
index 77d3c4ca4..3c1882aca 100644
--- a/packages/eslint-plugin-svelte/src/rule-types.ts
+++ b/packages/eslint-plugin-svelte/src/rule-types.ts
@@ -299,6 +299,11 @@ export interface RuleOptions {
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/shorthand-directive/
    */
   'svelte/shorthand-directive'?: Linter.RuleEntry<SvelteShorthandDirective>
+  /**
+   * use let instead of const for signals values
+   * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/signal-prefer-let/
+   */
+  'svelte/signal-prefer-let'?: Linter.RuleEntry<[]>
   /**
    * enforce order of attributes
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/sort-attributes/
diff --git a/packages/eslint-plugin-svelte/src/rules/signal-prefer-let.ts b/packages/eslint-plugin-svelte/src/rules/signal-prefer-let.ts
new file mode 100644
index 000000000..cf5043912
--- /dev/null
+++ b/packages/eslint-plugin-svelte/src/rules/signal-prefer-let.ts
@@ -0,0 +1,51 @@
+import type { TSESTree } from '@typescript-eslint/types';
+import { createRule } from '../utils';
+
+export default createRule('signal-prefer-let', {
+	meta: {
+		docs: {
+			description: 'use let instead of const for signals values',
+			category: 'Best Practices',
+			recommended: false
+		},
+		schema: [],
+		messages: {
+			useLet: "const is used for a signal value. Use 'let' instead."
+		},
+		type: 'suggestion',
+		fixable: 'code'
+	},
+	create(context) {
+		function preferLet(node: TSESTree.VariableDeclaration) {
+			if (node.kind !== 'const') {
+				return;
+			}
+			context.report({
+				node,
+				messageId: 'useLet',
+				fix: (fixer) => fixer.replaceTextRange([node.range[0], node.range[0] + 5], 'let')
+			});
+		}
+
+		return {
+			'VariableDeclaration > VariableDeclarator > CallExpression > Identifier'(
+				node: TSESTree.Identifier
+			) {
+				if (['$props', '$derived', '$state'].includes(node.name)) {
+					preferLet(node.parent.parent?.parent as TSESTree.VariableDeclaration);
+				}
+			},
+			'VariableDeclaration > VariableDeclarator > CallExpression > MemberExpression > Identifier'(
+				node: TSESTree.Identifier
+			) {
+				if (
+					node.name === 'by' &&
+					((node.parent as TSESTree.MemberExpression).object as TSESTree.Identifier).name ===
+						'$derived'
+				) {
+					preferLet(node.parent.parent?.parent?.parent as TSESTree.VariableDeclaration);
+				}
+			}
+		};
+	}
+});
diff --git a/packages/eslint-plugin-svelte/src/utils/rules.ts b/packages/eslint-plugin-svelte/src/utils/rules.ts
index af0dd20e6..653214bb1 100644
--- a/packages/eslint-plugin-svelte/src/utils/rules.ts
+++ b/packages/eslint-plugin-svelte/src/utils/rules.ts
@@ -59,6 +59,7 @@ import requireStoreReactiveAccess from '../rules/require-store-reactive-access';
 import requireStoresInit from '../rules/require-stores-init';
 import shorthandAttribute from '../rules/shorthand-attribute';
 import shorthandDirective from '../rules/shorthand-directive';
+import signalPreferLet from '../rules/signal-prefer-let';
 import sortAttributes from '../rules/sort-attributes';
 import spacedHtmlComment from '../rules/spaced-html-comment';
 import system from '../rules/system';
@@ -124,6 +125,7 @@ export const rules = [
 	requireStoresInit,
 	shorthandAttribute,
 	shorthandDirective,
+	signalPreferLet,
 	sortAttributes,
 	spacedHtmlComment,
 	system,
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml
new file mode 100644
index 000000000..b432886c3
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml
@@ -0,0 +1,12 @@
+- message: "const is used for a signal value. Use 'let' instead."
+  line: 2
+  column: 2
+- message: "const is used for a signal value. Use 'let' instead."
+  line: 3
+  column: 2
+- message: "const is used for a signal value. Use 'let' instead."
+  line: 4
+  column: 2
+- message: "const is used for a signal value. Use 'let' instead."
+  line: 5
+  column: 2
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-input.svelte
new file mode 100644
index 000000000..c62bac8b0
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-input.svelte
@@ -0,0 +1,6 @@
+<script>
+	const { prop } = $props();
+	const state = $state();
+	const derived = $derived(state + 1);
+	const derivedBy = $derived.by(() => prop + state);
+</script>
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-output.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-output.svelte
new file mode 100644
index 000000000..6b344da40
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-output.svelte
@@ -0,0 +1,6 @@
+<script>
+	let { prop } = $props();
+	let state = $state();
+	let derived = $derived(state + 1);
+	let derivedBy = $derived.by(() => prop + state);
+</script>
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte
new file mode 100644
index 000000000..720186465
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte
@@ -0,0 +1,3 @@
+<script>
+	let { value } = $props();
+</script>
diff --git a/packages/eslint-plugin-svelte/tests/src/rules/signal-prefer-let.ts b/packages/eslint-plugin-svelte/tests/src/rules/signal-prefer-let.ts
new file mode 100644
index 000000000..589f43e6e
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/src/rules/signal-prefer-let.ts
@@ -0,0 +1,12 @@
+import { RuleTester } from '../../utils/eslint-compat';
+import rule from '../../../src/rules/signal-prefer-let';
+import { loadTestCases } from '../../utils/utils';
+
+const tester = new RuleTester({
+	languageOptions: {
+		ecmaVersion: 2020,
+		sourceType: 'module'
+	}
+});
+
+tester.run('signal-prefer-let', rule as any, loadTestCases('signal-prefer-let'));

From 642e4dd8a6cc23bcbb05d8af0205d5789d968b9a Mon Sep 17 00:00:00 2001
From: Bob Fanger <bfanger@gmail.com>
Date: Sun, 30 Jun 2024 10:58:31 +0200
Subject: [PATCH 2/2] refactor: Instead of "signal", use wording used in the
 Svelte docs

---
 .changeset/proud-donuts-tickle.md             |  2 +-
 README.md                                     |  2 +-
 docs/rules.md                                 |  2 +-
 ...ignal-prefer-let.md => rune-prefer-let.md} | 18 ++++++-------
 .../eslint-plugin-svelte/src/rule-types.ts    | 10 +++----
 ...ignal-prefer-let.ts => rune-prefer-let.ts} | 26 ++++++++++++++-----
 .../eslint-plugin-svelte/src/utils/rules.ts   |  4 +--
 .../invalid/test01-errors.yaml                | 20 ++++++++++++++
 .../invalid/test01-input.svelte               |  3 +++
 .../invalid/test01-output.svelte              |  3 +++
 .../rune-prefer-let/valid/test01-input.svelte |  9 +++++++
 .../invalid/test01-errors.yaml                | 12 ---------
 .../valid/test01-input.svelte                 |  3 ---
 ...ignal-prefer-let.ts => rune-prefer-let.ts} |  4 +--
 14 files changed, 76 insertions(+), 42 deletions(-)
 rename docs/rules/{signal-prefer-let.md => rune-prefer-let.md} (65%)
 rename packages/eslint-plugin-svelte/src/rules/{signal-prefer-let.ts => rune-prefer-let.ts} (58%)
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-errors.yaml
 rename packages/eslint-plugin-svelte/tests/fixtures/rules/{signal-prefer-let => rune-prefer-let}/invalid/test01-input.svelte (82%)
 rename packages/eslint-plugin-svelte/tests/fixtures/rules/{signal-prefer-let => rune-prefer-let}/invalid/test01-output.svelte (82%)
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/valid/test01-input.svelte
 delete mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml
 delete mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte
 rename packages/eslint-plugin-svelte/tests/src/rules/{signal-prefer-let.ts => rune-prefer-let.ts} (60%)

diff --git a/.changeset/proud-donuts-tickle.md b/.changeset/proud-donuts-tickle.md
index a528563c8..68a2fbaf0 100644
--- a/.changeset/proud-donuts-tickle.md
+++ b/.changeset/proud-donuts-tickle.md
@@ -2,4 +2,4 @@
 'eslint-plugin-svelte': minor
 ---
 
-New svelte/signal-prefer-let rule
+New svelte/rune-prefer-let rule
diff --git a/README.md b/README.md
index 858bc4e52..b5bf563a5 100644
--- a/README.md
+++ b/README.md
@@ -430,7 +430,7 @@ These rules relate to better ways of doing things to help you avoid problems:
 | [svelte/require-event-dispatcher-types](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-event-dispatcher-types/) | require type parameters for `createEventDispatcher` |  |
 | [svelte/require-optimized-style-attribute](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-optimized-style-attribute/) | require style attributes that can be optimized |  |
 | [svelte/require-stores-init](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-stores-init/) | require initial value in store |  |
-| [svelte/signal-prefer-let](https://sveltejs.github.io/eslint-plugin-svelte/rules/signal-prefer-let/) | use let instead of const for signals values | :wrench: |
+| [svelte/rune-prefer-let](https://sveltejs.github.io/eslint-plugin-svelte/rules/rune-prefer-let/) | use let instead of const for reactive variables created by runes | :wrench: |
 | [svelte/valid-each-key](https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-each-key/) | enforce keys to use variables defined in the `{#each}` block |  |
 
 ## Stylistic Issues
diff --git a/docs/rules.md b/docs/rules.md
index d89287762..2412386c8 100644
--- a/docs/rules.md
+++ b/docs/rules.md
@@ -67,7 +67,7 @@ These rules relate to better ways of doing things to help you avoid problems:
 | [svelte/require-event-dispatcher-types](./rules/require-event-dispatcher-types.md)       | require type parameters for `createEventDispatcher`                                                                                       |          |
 | [svelte/require-optimized-style-attribute](./rules/require-optimized-style-attribute.md) | require style attributes that can be optimized                                                                                            |          |
 | [svelte/require-stores-init](./rules/require-stores-init.md)                             | require initial value in store                                                                                                            |          |
-| [svelte/signal-prefer-let](./rules/signal-prefer-let.md)                                 | use let instead of const for signals values                                                                                               | :wrench: |
+| [svelte/rune-prefer-let](./rules/rune-prefer-let.md)                                     | use let instead of const for reactive variables created by runes                                                                          | :wrench: |
 | [svelte/valid-each-key](./rules/valid-each-key.md)                                       | enforce keys to use variables defined in the `{#each}` block                                                                              |          |
 
 ## Stylistic Issues
diff --git a/docs/rules/signal-prefer-let.md b/docs/rules/rune-prefer-let.md
similarity index 65%
rename from docs/rules/signal-prefer-let.md
rename to docs/rules/rune-prefer-let.md
index 44f59a527..502d74fc1 100644
--- a/docs/rules/signal-prefer-let.md
+++ b/docs/rules/rune-prefer-let.md
@@ -1,22 +1,22 @@
 ---
 pageClass: 'rule-details'
 sidebarDepth: 0
-title: 'svelte/signal-prefer-let'
-description: 'use let instead of const for signals values'
+title: 'svelte/rune-prefer-let'
+description: 'use let instead of const for reactive variables created by runes'
 ---
 
-# svelte/signal-prefer-let
+# svelte/rune-prefer-let
 
-> use let instead of const for signals values
+> use let instead of const for reactive variables created by runes
 
 - :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> **_This rule has not been released yet._** </badge>
 - :wrench: The `--fix` option on the [command line](https://eslint.org/docs/user-guide/command-line-interface#fixing-problems) can automatically fix some of the problems reported by this rule.
 
 ## :book: Rule Details
 
-This rule reports whenever a signal is assigned to a const.
+This rule reports whenever a rune that creates a reactive value is assigned to a const.
 In JavaScript `const` are defined as immutable references which cannot be reassigned.
-Signals are by definition changing and are reassigned by Svelte's reactivity system.
+Reactive variables can be reassigned by Svelte's reactivity system.
 
 <ESLintCodeBlock fix>
 
@@ -24,7 +24,7 @@ Signals are by definition changing and are reassigned by Svelte's reactivity sys
 
 ```svelte
 <script>
-  /* eslint svelte/signal-prefer-let: "error" */
+  /* eslint svelte/rune-prefer-let: "error" */
 
   /* ✓ GOOD */
   let { value } = $props();
@@ -46,5 +46,5 @@ Nothing
 
 ## :mag: Implementation
 
-- [Rule source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/src/rules/signal-prefer-let.ts)
-- [Test source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/tests/src/rules/signal-prefer-let.ts)
+- [Rule source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/src/rules/rune-prefer-let.ts)
+- [Test source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/tests/src/rules/rune-prefer-let.ts)
diff --git a/packages/eslint-plugin-svelte/src/rule-types.ts b/packages/eslint-plugin-svelte/src/rule-types.ts
index 3c1882aca..1e65a9e90 100644
--- a/packages/eslint-plugin-svelte/src/rule-types.ts
+++ b/packages/eslint-plugin-svelte/src/rule-types.ts
@@ -289,6 +289,11 @@ export interface RuleOptions {
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/require-stores-init/
    */
   'svelte/require-stores-init'?: Linter.RuleEntry<[]>
+  /**
+   * use let instead of const for reactive variables created by runes
+   * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/rune-prefer-let/
+   */
+  'svelte/rune-prefer-let'?: Linter.RuleEntry<[]>
   /**
    * enforce use of shorthand syntax in attribute
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/shorthand-attribute/
@@ -299,11 +304,6 @@ export interface RuleOptions {
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/shorthand-directive/
    */
   'svelte/shorthand-directive'?: Linter.RuleEntry<SvelteShorthandDirective>
-  /**
-   * use let instead of const for signals values
-   * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/signal-prefer-let/
-   */
-  'svelte/signal-prefer-let'?: Linter.RuleEntry<[]>
   /**
    * enforce order of attributes
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/sort-attributes/
diff --git a/packages/eslint-plugin-svelte/src/rules/signal-prefer-let.ts b/packages/eslint-plugin-svelte/src/rules/rune-prefer-let.ts
similarity index 58%
rename from packages/eslint-plugin-svelte/src/rules/signal-prefer-let.ts
rename to packages/eslint-plugin-svelte/src/rules/rune-prefer-let.ts
index cf5043912..4e552ebc2 100644
--- a/packages/eslint-plugin-svelte/src/rules/signal-prefer-let.ts
+++ b/packages/eslint-plugin-svelte/src/rules/rune-prefer-let.ts
@@ -1,28 +1,29 @@
 import type { TSESTree } from '@typescript-eslint/types';
 import { createRule } from '../utils';
 
-export default createRule('signal-prefer-let', {
+export default createRule('rune-prefer-let', {
 	meta: {
 		docs: {
-			description: 'use let instead of const for signals values',
+			description: 'use let instead of const for reactive variables created by runes',
 			category: 'Best Practices',
 			recommended: false
 		},
 		schema: [],
 		messages: {
-			useLet: "const is used for a signal value. Use 'let' instead."
+			useLet: "const is used for a reactive variable from {{rune}}. Use 'let' instead."
 		},
 		type: 'suggestion',
 		fixable: 'code'
 	},
 	create(context) {
-		function preferLet(node: TSESTree.VariableDeclaration) {
+		function preferLet(node: TSESTree.VariableDeclaration, rune: string) {
 			if (node.kind !== 'const') {
 				return;
 			}
 			context.report({
 				node,
 				messageId: 'useLet',
+				data: { rune },
 				fix: (fixer) => fixer.replaceTextRange([node.range[0], node.range[0] + 5], 'let')
 			});
 		}
@@ -32,7 +33,7 @@ export default createRule('signal-prefer-let', {
 				node: TSESTree.Identifier
 			) {
 				if (['$props', '$derived', '$state'].includes(node.name)) {
-					preferLet(node.parent.parent?.parent as TSESTree.VariableDeclaration);
+					preferLet(node.parent.parent?.parent as TSESTree.VariableDeclaration, `${node.name}()`);
 				}
 			},
 			'VariableDeclaration > VariableDeclarator > CallExpression > MemberExpression > Identifier'(
@@ -43,7 +44,20 @@ export default createRule('signal-prefer-let', {
 					((node.parent as TSESTree.MemberExpression).object as TSESTree.Identifier).name ===
 						'$derived'
 				) {
-					preferLet(node.parent.parent?.parent?.parent as TSESTree.VariableDeclaration);
+					preferLet(
+						node.parent.parent?.parent?.parent as TSESTree.VariableDeclaration,
+						'$derived.by()'
+					);
+				}
+				if (
+					node.name === 'frozen' &&
+					((node.parent as TSESTree.MemberExpression).object as TSESTree.Identifier).name ===
+						'$state'
+				) {
+					preferLet(
+						node.parent.parent?.parent?.parent as TSESTree.VariableDeclaration,
+						'$state.frozen()'
+					);
 				}
 			}
 		};
diff --git a/packages/eslint-plugin-svelte/src/utils/rules.ts b/packages/eslint-plugin-svelte/src/utils/rules.ts
index 653214bb1..17f168121 100644
--- a/packages/eslint-plugin-svelte/src/utils/rules.ts
+++ b/packages/eslint-plugin-svelte/src/utils/rules.ts
@@ -57,9 +57,9 @@ import requireOptimizedStyleAttribute from '../rules/require-optimized-style-att
 import requireStoreCallbacksUseSetParam from '../rules/require-store-callbacks-use-set-param';
 import requireStoreReactiveAccess from '../rules/require-store-reactive-access';
 import requireStoresInit from '../rules/require-stores-init';
+import runePreferLet from '../rules/rune-prefer-let';
 import shorthandAttribute from '../rules/shorthand-attribute';
 import shorthandDirective from '../rules/shorthand-directive';
-import signalPreferLet from '../rules/signal-prefer-let';
 import sortAttributes from '../rules/sort-attributes';
 import spacedHtmlComment from '../rules/spaced-html-comment';
 import system from '../rules/system';
@@ -123,9 +123,9 @@ export const rules = [
 	requireStoreCallbacksUseSetParam,
 	requireStoreReactiveAccess,
 	requireStoresInit,
+	runePreferLet,
 	shorthandAttribute,
 	shorthandDirective,
-	signalPreferLet,
 	sortAttributes,
 	spacedHtmlComment,
 	system,
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-errors.yaml
new file mode 100644
index 000000000..43caffafb
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-errors.yaml
@@ -0,0 +1,20 @@
+- message: const is used for a reactive variable from $props(). Use 'let' instead.
+  line: 2
+  column: 2
+  suggestions: null
+- message: const is used for a reactive variable from $state(). Use 'let' instead.
+  line: 4
+  column: 2
+  suggestions: null
+- message: const is used for a reactive variable from $state.frozen(). Use 'let' instead.
+  line: 5
+  column: 2
+  suggestions: null
+- message: const is used for a reactive variable from $derived(). Use 'let' instead.
+  line: 7
+  column: 2
+  suggestions: null
+- message: const is used for a reactive variable from $derived.by(). Use 'let' instead.
+  line: 8
+  column: 2
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-input.svelte
similarity index 82%
rename from packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-input.svelte
rename to packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-input.svelte
index c62bac8b0..942055dce 100644
--- a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-input.svelte
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-input.svelte
@@ -1,6 +1,9 @@
 <script>
 	const { prop } = $props();
+
 	const state = $state();
+	const frozen = $state.frozen();
+
 	const derived = $derived(state + 1);
 	const derivedBy = $derived.by(() => prop + state);
 </script>
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-output.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-output.svelte
similarity index 82%
rename from packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-output.svelte
rename to packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-output.svelte
index 6b344da40..ad50f1d6e 100644
--- a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-output.svelte
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/invalid/test01-output.svelte
@@ -1,6 +1,9 @@
 <script>
 	let { prop } = $props();
+
 	let state = $state();
+	let frozen = $state.frozen();
+
 	let derived = $derived(state + 1);
 	let derivedBy = $derived.by(() => prop + state);
 </script>
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/valid/test01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/valid/test01-input.svelte
new file mode 100644
index 000000000..ad50f1d6e
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/rune-prefer-let/valid/test01-input.svelte
@@ -0,0 +1,9 @@
+<script>
+	let { prop } = $props();
+
+	let state = $state();
+	let frozen = $state.frozen();
+
+	let derived = $derived(state + 1);
+	let derivedBy = $derived.by(() => prop + state);
+</script>
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml
deleted file mode 100644
index b432886c3..000000000
--- a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/invalid/test01-errors.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
-- message: "const is used for a signal value. Use 'let' instead."
-  line: 2
-  column: 2
-- message: "const is used for a signal value. Use 'let' instead."
-  line: 3
-  column: 2
-- message: "const is used for a signal value. Use 'let' instead."
-  line: 4
-  column: 2
-- message: "const is used for a signal value. Use 'let' instead."
-  line: 5
-  column: 2
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte
deleted file mode 100644
index 720186465..000000000
--- a/packages/eslint-plugin-svelte/tests/fixtures/rules/signal-prefer-let/valid/test01-input.svelte
+++ /dev/null
@@ -1,3 +0,0 @@
-<script>
-	let { value } = $props();
-</script>
diff --git a/packages/eslint-plugin-svelte/tests/src/rules/signal-prefer-let.ts b/packages/eslint-plugin-svelte/tests/src/rules/rune-prefer-let.ts
similarity index 60%
rename from packages/eslint-plugin-svelte/tests/src/rules/signal-prefer-let.ts
rename to packages/eslint-plugin-svelte/tests/src/rules/rune-prefer-let.ts
index 589f43e6e..a7e923a3d 100644
--- a/packages/eslint-plugin-svelte/tests/src/rules/signal-prefer-let.ts
+++ b/packages/eslint-plugin-svelte/tests/src/rules/rune-prefer-let.ts
@@ -1,5 +1,5 @@
 import { RuleTester } from '../../utils/eslint-compat';
-import rule from '../../../src/rules/signal-prefer-let';
+import rule from '../../../src/rules/rune-prefer-let';
 import { loadTestCases } from '../../utils/utils';
 
 const tester = new RuleTester({
@@ -9,4 +9,4 @@ const tester = new RuleTester({
 	}
 });
 
-tester.run('signal-prefer-let', rule as any, loadTestCases('signal-prefer-let'));
+tester.run('rune-prefer-let', rule as any, loadTestCases('rune-prefer-let'));