diff --git a/.changeset/rich-colts-nail.md b/.changeset/rich-colts-nail.md
new file mode 100644
index 000000000..51c8eea60
--- /dev/null
+++ b/.changeset/rich-colts-nail.md
@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': minor
+---
+
+feat: added the `prefer-svelte-reactivity` rule
diff --git a/README.md b/README.md
index 9cccc33bd..c8018284f 100644
--- a/README.md
+++ b/README.md
@@ -273,6 +273,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-store-async](https://sveltejs.github.io/eslint-plugin-svelte/rules/no-store-async/) | disallow using async/await inside svelte stores because it causes issues with the auto-unsubscribing features | :star: |
 | [svelte/no-top-level-browser-globals](https://sveltejs.github.io/eslint-plugin-svelte/rules/no-top-level-browser-globals/) | disallow using top-level browser global variables |  |
 | [svelte/no-unknown-style-directive-property](https://sveltejs.github.io/eslint-plugin-svelte/rules/no-unknown-style-directive-property/) | disallow unknown `style:property` | :star: |
+| [svelte/prefer-svelte-reactivity](https://sveltejs.github.io/eslint-plugin-svelte/rules/prefer-svelte-reactivity/) | disallow using mutable instances of built-in classes where a reactive alternative is provided by svelte/reactivity | :star: |
 | [svelte/require-store-callbacks-use-set-param](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-store-callbacks-use-set-param/) | store callbacks must use `set` param | :bulb: |
 | [svelte/require-store-reactive-access](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-store-reactive-access/) | disallow to use of the store itself as an operand. Need to use $ prefix or get function. | :star::wrench: |
 | [svelte/valid-compile](https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-compile/) | disallow warnings when compiling. |  |
diff --git a/docs/rules.md b/docs/rules.md
index 459eb2ae4..3465a4066 100644
--- a/docs/rules.md
+++ b/docs/rules.md
@@ -30,6 +30,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-store-async](./rules/no-store-async.md)                                               | disallow using async/await inside svelte stores because it causes issues with the auto-unsubscribing features                          | :star:         |
 | [svelte/no-top-level-browser-globals](./rules/no-top-level-browser-globals.md)                   | disallow using top-level browser global variables                                                                                      |                |
 | [svelte/no-unknown-style-directive-property](./rules/no-unknown-style-directive-property.md)     | disallow unknown `style:property`                                                                                                      | :star:         |
+| [svelte/prefer-svelte-reactivity](./rules/prefer-svelte-reactivity.md)                           | disallow using mutable instances of built-in classes where a reactive alternative is provided by svelte/reactivity                     | :star:         |
 | [svelte/require-store-callbacks-use-set-param](./rules/require-store-callbacks-use-set-param.md) | store callbacks must use `set` param                                                                                                   | :bulb:         |
 | [svelte/require-store-reactive-access](./rules/require-store-reactive-access.md)                 | disallow to use of the store itself as an operand. Need to use $ prefix or get function.                                               | :star::wrench: |
 | [svelte/valid-compile](./rules/valid-compile.md)                                                 | disallow warnings when compiling.                                                                                                      |                |
diff --git a/docs/rules/prefer-svelte-reactivity.md b/docs/rules/prefer-svelte-reactivity.md
new file mode 100644
index 000000000..7b3fe8236
--- /dev/null
+++ b/docs/rules/prefer-svelte-reactivity.md
@@ -0,0 +1,117 @@
+---
+pageClass: 'rule-details'
+sidebarDepth: 0
+title: 'svelte/prefer-svelte-reactivity'
+description: 'disallow using mutable instances of built-in classes where a reactive alternative is provided by svelte/reactivity'
+---
+
+# svelte/prefer-svelte-reactivity
+
+> disallow using mutable instances of built-in classes where a reactive alternative is provided by svelte/reactivity
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> **_This rule has not been released yet._** </badge>
+- :gear: This rule is included in `"plugin:svelte/recommended"`.
+
+## :book: Rule Details
+
+The built-in `Date`, `Map`, `Set`, `URL` and `URLSearchParams` classes are often used in frontend code, however, their properties and methods are not reactive. Because of that, Svelte provides reactive versions of these 5 builtins as part of the "svelte/reactivity" package. This rule reports usage of mutable instances of the built-in versions in Svelte code.
+
+<!--eslint-skip-->
+
+```svelte
+<script>
+  /* eslint svelte/prefer-svelte-reactivity: "error" */
+
+  import {
+    SvelteDate,
+    SvelteMap,
+    SvelteSet,
+    SvelteURL,
+    SvelteURLSearchParams
+  } from 'svelte/reactivity';
+
+  /* ✓ GOOD */
+
+  const a = new Date(8.64e15);
+  const b = new Map([
+    [1, 'one'],
+    [2, 'two']
+  ]);
+  const c = new Set([1, 2, 1, 3, 3]);
+  const d = new URL('https://svelte.dev/');
+  const e = new URLSearchParams('foo=1&bar=2');
+
+  // These don't modify the instances
+  a.getTime();
+  b.keys();
+  c.has(1);
+  d.port;
+  e.entries();
+
+  const f = new SvelteDate(8.64e15);
+  const g = new SvelteMap([
+    [1, 'one'],
+    [2, 'two']
+  ]);
+  const h = new SvelteSet([1, 2, 1, 3, 3]);
+  const i = new SvelteURL('https://svelte.dev/');
+  const j = new SvelteURLSearchParams('foo=1&bar=2');
+
+  // These modify the instances
+  f.getTime();
+  g.keys();
+  h.has(1);
+  i.port;
+  j.entries();
+
+  /* ✗ BAD */
+
+  const k = new Date(8.64e15);
+  const l = new Map([
+    [1, 'one'],
+    [2, 'two']
+  ]);
+  const m = new Set([1, 2, 1, 3, 3]);
+  const n = new URL('https://svelte.dev/');
+  const o = new URLSearchParams('foo=1&bar=2');
+
+  // These modify the instances
+  k.setMonth(3);
+  l.clear();
+  m.delete(2);
+  n.port = 80;
+  o.sort();
+</script>
+```
+
+```js
+// In svelte.js files, exported variables are also reported
+/* eslint svelte/prefer-svelte-reactivity: "error" */
+
+/* ✗ BAD */
+
+const a = new Date(8.64e15);
+const b = new Map([
+  [1, 'one'],
+  [2, 'two']
+]);
+const c = new Set([1, 2, 1, 3, 3]);
+const d = new URL('https://svelte.dev/');
+const e = new URLSearchParams('foo=1&bar=2');
+
+export { a, b, c, d as dd };
+export default e;
+```
+
+## :wrench: Options
+
+Nothing.
+
+## :books: Further Reading
+
+- [svelte/reactivity documentation](https://svelte.dev/docs/svelte/svelte-reactivity)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/packages/eslint-plugin-svelte/src/rules/prefer-svelte-reactivity.ts)
+- [Test source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/packages/eslint-plugin-svelte/tests/src/rules/prefer-svelte-reactivity.ts)
diff --git a/packages/eslint-plugin-svelte/src/configs/flat/recommended.ts b/packages/eslint-plugin-svelte/src/configs/flat/recommended.ts
index 7a08befc8..1f950a90f 100644
--- a/packages/eslint-plugin-svelte/src/configs/flat/recommended.ts
+++ b/packages/eslint-plugin-svelte/src/configs/flat/recommended.ts
@@ -37,6 +37,7 @@ const config: Linter.Config[] = [
 			'svelte/no-unused-svelte-ignore': 'error',
 			'svelte/no-useless-children-snippet': 'error',
 			'svelte/no-useless-mustaches': 'error',
+			'svelte/prefer-svelte-reactivity': 'error',
 			'svelte/prefer-writable-derived': 'error',
 			'svelte/require-each-key': 'error',
 			'svelte/require-event-dispatcher-types': 'error',
diff --git a/packages/eslint-plugin-svelte/src/rule-types.ts b/packages/eslint-plugin-svelte/src/rule-types.ts
index 81657270d..f4fd5c81d 100644
--- a/packages/eslint-plugin-svelte/src/rule-types.ts
+++ b/packages/eslint-plugin-svelte/src/rule-types.ts
@@ -316,6 +316,11 @@ export interface RuleOptions {
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/prefer-style-directive/
    */
   'svelte/prefer-style-directive'?: Linter.RuleEntry<[]>
+  /**
+   * disallow using mutable instances of built-in classes where a reactive alternative is provided by svelte/reactivity
+   * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/prefer-svelte-reactivity/
+   */
+  'svelte/prefer-svelte-reactivity'?: Linter.RuleEntry<[]>
   /**
    * Prefer using writable $derived instead of $state and $effect
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/prefer-writable-derived/
diff --git a/packages/eslint-plugin-svelte/src/rules/prefer-svelte-reactivity.ts b/packages/eslint-plugin-svelte/src/rules/prefer-svelte-reactivity.ts
new file mode 100644
index 000000000..7118b054d
--- /dev/null
+++ b/packages/eslint-plugin-svelte/src/rules/prefer-svelte-reactivity.ts
@@ -0,0 +1,285 @@
+import { ReferenceTracker } from '@eslint-community/eslint-utils';
+import { createRule } from '../utils/index.js';
+import type { TSESTree } from '@typescript-eslint/types';
+import { findVariable, isIn } from '../utils/ast-utils.js';
+import { getSvelteContext } from '../utils/svelte-context.js';
+
+export default createRule('prefer-svelte-reactivity', {
+	meta: {
+		docs: {
+			description:
+				'disallow using mutable instances of built-in classes where a reactive alternative is provided by svelte/reactivity',
+			category: 'Possible Errors',
+			recommended: true
+		},
+		schema: [],
+		messages: {
+			mutableDateUsed:
+				'Found a mutable instance of the built-in Date class. Use SvelteDate instead.',
+			mutableMapUsed: 'Found a mutable instance of the built-in Map class. Use SvelteMap instead.',
+			mutableSetUsed: 'Found a mutable instance of the built-in Set class. Use SvelteSet instead.',
+			mutableURLUsed: 'Found a mutable instance of the built-in URL class. Use SvelteURL instead.',
+			mutableURLSearchParamsUsed:
+				'Found a mutable instance of the built-in URLSearchParams class. Use SvelteURLSearchParams instead.'
+		},
+		type: 'problem',
+		conditions: [
+			{
+				svelteVersions: ['5'],
+				svelteFileTypes: ['.svelte', '.svelte.[js|ts]']
+			}
+		]
+	},
+	create(context) {
+		const exportedVars: TSESTree.Node[] = [];
+		return {
+			...(getSvelteContext(context)?.svelteFileType === '.svelte.[js|ts]' && {
+				ExportNamedDeclaration(node) {
+					if (node.declaration !== null) {
+						exportedVars.push(node.declaration);
+					}
+					for (const specifier of node.specifiers) {
+						if (specifier.local.type !== 'Identifier') {
+							continue;
+						}
+						const defs = findVariable(context, specifier.local)?.defs ?? [];
+						for (const def of defs) {
+							exportedVars.push(def.node);
+						}
+					}
+				},
+				ExportDefaultDeclaration(node) {
+					if (node.declaration.type === 'Identifier') {
+						const defs = findVariable(context, node.declaration)?.defs ?? [];
+						for (const def of defs) {
+							exportedVars.push(def.node);
+						}
+					} else {
+						exportedVars.push(node.declaration);
+					}
+				}
+			}),
+			'Program:exit'() {
+				const referenceTracker = new ReferenceTracker(context.sourceCode.scopeManager.globalScope!);
+				for (const { node, path } of referenceTracker.iterateGlobalReferences({
+					Date: {
+						[ReferenceTracker.CONSTRUCT]: true
+					},
+					Map: {
+						[ReferenceTracker.CONSTRUCT]: true
+					},
+					Set: {
+						[ReferenceTracker.CONSTRUCT]: true
+					},
+					URL: {
+						[ReferenceTracker.CONSTRUCT]: true
+					},
+					URLSearchParams: {
+						[ReferenceTracker.CONSTRUCT]: true
+					}
+				})) {
+					const messageId =
+						path[0] === 'Date'
+							? 'mutableDateUsed'
+							: path[0] === 'Map'
+								? 'mutableMapUsed'
+								: path[0] === 'Set'
+									? 'mutableSetUsed'
+									: path[0] === 'URL'
+										? 'mutableURLUsed'
+										: 'mutableURLSearchParamsUsed';
+					for (const exportedVar of exportedVars) {
+						if (isIn(node, exportedVar)) {
+							context.report({
+								messageId,
+								node
+							});
+						}
+					}
+					if (path[0] === 'Date' && isDateMutable(referenceTracker, node as TSESTree.Expression)) {
+						context.report({
+							messageId: 'mutableDateUsed',
+							node
+						});
+					}
+					if (path[0] === 'Map' && isMapMutable(referenceTracker, node as TSESTree.Expression)) {
+						context.report({
+							messageId: 'mutableMapUsed',
+							node
+						});
+					}
+					if (path[0] === 'Set' && isSetMutable(referenceTracker, node as TSESTree.Expression)) {
+						context.report({
+							messageId: 'mutableSetUsed',
+							node
+						});
+					}
+					if (path[0] === 'URL' && isURLMutable(referenceTracker, node as TSESTree.Expression)) {
+						context.report({
+							messageId: 'mutableURLUsed',
+							node
+						});
+					}
+					if (
+						path[0] === 'URLSearchParams' &&
+						isURLSearchParamsMutable(referenceTracker, node as TSESTree.Expression)
+					) {
+						context.report({
+							messageId: 'mutableURLSearchParamsUsed',
+							node
+						});
+					}
+				}
+			}
+		};
+	}
+});
+
+function isDateMutable(referenceTracker: ReferenceTracker, ctorNode: TSESTree.Expression): boolean {
+	return !referenceTracker
+		.iteratePropertyReferences(ctorNode, {
+			setDate: {
+				[ReferenceTracker.CALL]: true
+			},
+			setFullYear: {
+				[ReferenceTracker.CALL]: true
+			},
+			setHours: {
+				[ReferenceTracker.CALL]: true
+			},
+			setMilliseconds: {
+				[ReferenceTracker.CALL]: true
+			},
+			setMinutes: {
+				[ReferenceTracker.CALL]: true
+			},
+			setMonth: {
+				[ReferenceTracker.CALL]: true
+			},
+			setSeconds: {
+				[ReferenceTracker.CALL]: true
+			},
+			setTime: {
+				[ReferenceTracker.CALL]: true
+			},
+			setUTCDate: {
+				[ReferenceTracker.CALL]: true
+			},
+			setUTCFullYear: {
+				[ReferenceTracker.CALL]: true
+			},
+			setUTCHours: {
+				[ReferenceTracker.CALL]: true
+			},
+			setUTCMilliseconds: {
+				[ReferenceTracker.CALL]: true
+			},
+			setUTCMinutes: {
+				[ReferenceTracker.CALL]: true
+			},
+			setUTCMonth: {
+				[ReferenceTracker.CALL]: true
+			},
+			setUTCSeconds: {
+				[ReferenceTracker.CALL]: true
+			},
+			setYear: {
+				[ReferenceTracker.CALL]: true
+			}
+		})
+		.next().done;
+}
+
+function isMapMutable(referenceTracker: ReferenceTracker, ctorNode: TSESTree.Expression): boolean {
+	return !referenceTracker
+		.iteratePropertyReferences(ctorNode, {
+			clear: {
+				[ReferenceTracker.CALL]: true
+			},
+			delete: {
+				[ReferenceTracker.CALL]: true
+			},
+			set: {
+				[ReferenceTracker.CALL]: true
+			}
+		})
+		.next().done;
+}
+
+function isSetMutable(referenceTracker: ReferenceTracker, ctorNode: TSESTree.Expression): boolean {
+	return !referenceTracker
+		.iteratePropertyReferences(ctorNode, {
+			add: {
+				[ReferenceTracker.CALL]: true
+			},
+			clear: {
+				[ReferenceTracker.CALL]: true
+			},
+			delete: {
+				[ReferenceTracker.CALL]: true
+			}
+		})
+		.next().done;
+}
+
+function isURLMutable(referenceTracker: ReferenceTracker, ctorNode: TSESTree.Expression): boolean {
+	for (const { node } of referenceTracker.iteratePropertyReferences(ctorNode, {
+		hash: {
+			[ReferenceTracker.READ]: true
+		},
+		host: {
+			[ReferenceTracker.READ]: true
+		},
+		hostname: {
+			[ReferenceTracker.READ]: true
+		},
+		href: {
+			[ReferenceTracker.READ]: true
+		},
+		password: {
+			[ReferenceTracker.READ]: true
+		},
+		pathname: {
+			[ReferenceTracker.READ]: true
+		},
+		port: {
+			[ReferenceTracker.READ]: true
+		},
+		protocol: {
+			[ReferenceTracker.READ]: true
+		},
+		search: {
+			[ReferenceTracker.READ]: true
+		},
+		username: {
+			[ReferenceTracker.READ]: true
+		}
+	})) {
+		if (node.parent.type === 'AssignmentExpression' && node.parent.left === node) {
+			return true;
+		}
+	}
+	return false;
+}
+
+function isURLSearchParamsMutable(
+	referenceTracker: ReferenceTracker,
+	ctorNode: TSESTree.Expression
+): boolean {
+	return !referenceTracker
+		.iteratePropertyReferences(ctorNode, {
+			append: {
+				[ReferenceTracker.CALL]: true
+			},
+			delete: {
+				[ReferenceTracker.CALL]: true
+			},
+			set: {
+				[ReferenceTracker.CALL]: true
+			},
+			sort: {
+				[ReferenceTracker.CALL]: true
+			}
+		})
+		.next().done;
+}
diff --git a/packages/eslint-plugin-svelte/src/utils/ast-utils.ts b/packages/eslint-plugin-svelte/src/utils/ast-utils.ts
index bff6c0951..e36a9cf75 100644
--- a/packages/eslint-plugin-svelte/src/utils/ast-utils.ts
+++ b/packages/eslint-plugin-svelte/src/utils/ast-utils.ts
@@ -722,3 +722,16 @@ export function findVariableForReplacement(
 
 	return { hasConflict: false, variable };
 }
+
+/**
+ * Check if one node is contained withing the subtree of another node.
+ */
+export function isIn(needle: TSESTree.Node, haystack: TSESTree.Node): boolean {
+	if (needle === haystack) {
+		return true;
+	}
+	if (needle.parent == null) {
+		return false;
+	}
+	return isIn(needle.parent, haystack);
+}
diff --git a/packages/eslint-plugin-svelte/src/utils/rules.ts b/packages/eslint-plugin-svelte/src/utils/rules.ts
index bc62cc8c6..fa43f58b7 100644
--- a/packages/eslint-plugin-svelte/src/utils/rules.ts
+++ b/packages/eslint-plugin-svelte/src/utils/rules.ts
@@ -62,6 +62,7 @@ import preferClassDirective from '../rules/prefer-class-directive.js';
 import preferConst from '../rules/prefer-const.js';
 import preferDestructuredStoreProps from '../rules/prefer-destructured-store-props.js';
 import preferStyleDirective from '../rules/prefer-style-directive.js';
+import preferSvelteReactivity from '../rules/prefer-svelte-reactivity.js';
 import preferWritableDerived from '../rules/prefer-writable-derived.js';
 import requireEachKey from '../rules/require-each-key.js';
 import requireEventDispatcherTypes from '../rules/require-event-dispatcher-types.js';
@@ -141,6 +142,7 @@ export const rules = [
 	preferConst,
 	preferDestructuredStoreProps,
 	preferStyleDirective,
+	preferSvelteReactivity,
 	preferWritableDerived,
 	requireEachKey,
 	requireEventDispatcherTypes,
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/_requirements.json b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/_requirements.json
new file mode 100644
index 000000000..498661308
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/_requirements.json
@@ -0,0 +1,3 @@
+{
+	"svelte": ">=5.0.0"
+}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/_requirements.json b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/_requirements.json
new file mode 100644
index 000000000..498661308
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/_requirements.json
@@ -0,0 +1,3 @@
+{
+	"svelte": ">=5.0.0"
+}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setDate01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setDate01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setDate01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setDate01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setDate01-input.svelte
new file mode 100644
index 000000000..11833e43b
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setDate01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setDate(24);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear01-input.svelte
new file mode 100644
index 000000000..1a64fb628
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setFullYear(1968);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear02-input.svelte
new file mode 100644
index 000000000..5dc33f13d
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setFullYear(1968, 10);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear03-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear03-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear03-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear03-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear03-input.svelte
new file mode 100644
index 000000000..eb794f8df
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setFullYear03-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setFullYear(1968, 10, 3);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours01-input.svelte
new file mode 100644
index 000000000..ff3e11e6c
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setHours(23);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours02-input.svelte
new file mode 100644
index 000000000..481cfda04
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setHours(23, 59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours03-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours03-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours03-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours03-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours03-input.svelte
new file mode 100644
index 000000000..be277bc8f
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours03-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setHours(23, 59, 59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours04-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours04-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours04-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours04-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours04-input.svelte
new file mode 100644
index 000000000..b379006f1
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setHours04-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setHours(23, 59, 59, 999);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMilliseconds01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMilliseconds01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMilliseconds01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMilliseconds01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMilliseconds01-input.svelte
new file mode 100644
index 000000000..ca160205a
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMilliseconds01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setMilliseconds(999);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes01-input.svelte
new file mode 100644
index 000000000..038ba40ad
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setMinutes(59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes02-input.svelte
new file mode 100644
index 000000000..8d9a9cecb
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setMinutes(59, 59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes03-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes03-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes03-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes03-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes03-input.svelte
new file mode 100644
index 000000000..51ac2cdba
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMinutes03-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setMinutes(59, 59, 999);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth01-input.svelte
new file mode 100644
index 000000000..2d1fd09ba
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setMonth(11);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth02-input.svelte
new file mode 100644
index 000000000..cb026f1dc
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setMonth02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setMonth(11, 23);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds01-input.svelte
new file mode 100644
index 000000000..80e967356
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setSeconds(59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds02-input.svelte
new file mode 100644
index 000000000..73e352bc1
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setSeconds02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setSeconds(59, 999);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setTime01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setTime01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setTime01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setTime01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setTime01-input.svelte
new file mode 100644
index 000000000..acb7f19e4
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setTime01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setTime(123456);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCDate01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCDate01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCDate01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCDate01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCDate01-input.svelte
new file mode 100644
index 000000000..f0069650a
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCDate01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCDate(23);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear01-input.svelte
new file mode 100644
index 000000000..b397a2096
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCFullYear(1968);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear02-input.svelte
new file mode 100644
index 000000000..04dce5751
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCFullYear(1968, 10);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear03-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear03-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear03-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear03-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear03-input.svelte
new file mode 100644
index 000000000..bbd843373
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCFullYear03-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCFullYear(1968, 10, 3);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours01-input.svelte
new file mode 100644
index 000000000..6d005cb30
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCHours(23);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours02-input.svelte
new file mode 100644
index 000000000..254653e9c
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCHours(23, 59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours03-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours03-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours03-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours03-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours03-input.svelte
new file mode 100644
index 000000000..0d17f2371
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours03-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCHours(23, 59, 59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours04-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours04-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours04-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours04-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours04-input.svelte
new file mode 100644
index 000000000..1d6a73acb
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCHours04-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCHours(23, 59, 59, 999);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMilliseconds01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMilliseconds01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMilliseconds01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMilliseconds01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMilliseconds01-input.svelte
new file mode 100644
index 000000000..62da2355e
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMilliseconds01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCMilliseconds(420);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes01-input.svelte
new file mode 100644
index 000000000..6905d0e00
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCMinutes(59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes02-input.svelte
new file mode 100644
index 000000000..23fdfbfec
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCMinutes(59, 59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes03-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes03-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes03-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes03-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes03-input.svelte
new file mode 100644
index 000000000..496b29116
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMinutes03-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCMinutes(59, 59, 999);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth01-input.svelte
new file mode 100644
index 000000000..b1beb0b4e
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCMonth(10);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth02-input.svelte
new file mode 100644
index 000000000..04b5782f6
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCMonth02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCMonth(10, 3);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds01-input.svelte
new file mode 100644
index 000000000..9b5a457da
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCSeconds(59);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds02-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds02-input.svelte
new file mode 100644
index 000000000..13b9bf0f5
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setUTCSeconds02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setUTCSeconds(59, 999);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setYear01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setYear01-errors.yaml
new file mode 100644
index 000000000..e0715f2aa
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setYear01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setYear01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setYear01-input.svelte
new file mode 100644
index 000000000..982ae71bf
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date/setYear01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Date(8.64e15);
+
+  variable.setYear(1968);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports01-errors.yaml
new file mode 100644
index 000000000..16ae06562
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports01-errors.yaml
@@ -0,0 +1,29 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 1
+  column: 19
+  suggestions: null
+- message: Found a mutable instance of the built-in Map class. Use SvelteMap instead.
+  line: 2
+  column: 19
+  suggestions: null
+- message: Found a mutable instance of the built-in Set class. Use SvelteSet instead.
+  line: 3
+  column: 19
+  suggestions: null
+- message: Found a mutable instance of the built-in URLSearchParams class. Use
+    SvelteURLSearchParams instead.
+  line: 4
+  column: 19
+  suggestions: null
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 5
+  column: 19
+  suggestions: null
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 6
+  column: 19
+  suggestions: null
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 10
+  column: 26
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports01-input.svelte.js b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports01-input.svelte.js
new file mode 100644
index 000000000..1c902ea7a
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports01-input.svelte.js
@@ -0,0 +1,10 @@
+const variable1 = new Date(8.64e15);
+const variable2 = new Map([[1, "one"], [2, "two"]]);
+const variable3 = new Set([1, 2, 1, 3, 3]);
+const variable4 = new URLSearchParams("foo=1&bar=2");
+const variable5 = new URL("https://svelte.dev/");
+const variable6 = new Date(8.64e15);
+
+export {variable1, variable2, variable3, variable4, variable5, variable6 as var};
+
+export const variable7 = new Date(8.64e15);
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports02-errors.yaml
new file mode 100644
index 000000000..2401e0107
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports02-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 1
+  column: 19
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports02-input.svelte.js b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports02-input.svelte.js
new file mode 100644
index 000000000..24fb4f6f4
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports02-input.svelte.js
@@ -0,0 +1,3 @@
+const variable1 = new Date(8.64e15);
+
+export default variable1;
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports03-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports03-errors.yaml
new file mode 100644
index 000000000..8806ddea8
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports03-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 1
+  column: 16
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports03-input.svelte.js b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports03-input.svelte.js
new file mode 100644
index 000000000..5bc61d219
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports03-input.svelte.js
@@ -0,0 +1 @@
+export default new Date(8.64e15);
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports04-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports04-errors.yaml
new file mode 100644
index 000000000..2401e0107
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports04-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Date class. Use SvelteDate instead.
+  line: 1
+  column: 19
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports04-input.svelte.js b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports04-input.svelte.js
new file mode 100644
index 000000000..0a392488a
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/exports04-input.svelte.js
@@ -0,0 +1,3 @@
+const variable1 = new Date(8.64e15);
+
+export { variable1 as default };
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/_requirements.json b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/_requirements.json
new file mode 100644
index 000000000..498661308
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/_requirements.json
@@ -0,0 +1,3 @@
+{
+	"svelte": ">=5.0.0"
+}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/clear01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/clear01-errors.yaml
new file mode 100644
index 000000000..9290e26c4
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/clear01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Map class. Use SvelteMap instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/clear01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/clear01-input.svelte
new file mode 100644
index 000000000..076f3c718
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/clear01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Map([[1, "one"], [2, "two"]]);
+
+  variable.clear();
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/delete01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/delete01-errors.yaml
new file mode 100644
index 000000000..9290e26c4
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/delete01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Map class. Use SvelteMap instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/delete01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/delete01-input.svelte
new file mode 100644
index 000000000..b46d846e6
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/delete01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Map([[1, "one"], [2, "two"]]);
+
+  variable.delete(1);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/set01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/set01-errors.yaml
new file mode 100644
index 000000000..9290e26c4
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/set01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Map class. Use SvelteMap instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/set01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/set01-input.svelte
new file mode 100644
index 000000000..6ec9bf26c
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map/set01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Map([[1, "one"], [2, "two"]]);
+
+  variable.set(1, "two");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/_requirements.json b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/_requirements.json
new file mode 100644
index 000000000..498661308
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/_requirements.json
@@ -0,0 +1,3 @@
+{
+	"svelte": ">=5.0.0"
+}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/add01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/add01-errors.yaml
new file mode 100644
index 000000000..b7ff0cd9b
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/add01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Set class. Use SvelteSet instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/add01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/add01-input.svelte
new file mode 100644
index 000000000..f2fe183c2
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/add01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Set([1, 2, 1, 3, 3]);
+
+  variable.add(42);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/clear01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/clear01-errors.yaml
new file mode 100644
index 000000000..b7ff0cd9b
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/clear01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Set class. Use SvelteSet instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/clear01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/clear01-input.svelte
new file mode 100644
index 000000000..2177c4bb5
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/clear01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Set([1, 2, 1, 3, 3]);
+
+  variable.clear();
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/delete01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/delete01-errors.yaml
new file mode 100644
index 000000000..b7ff0cd9b
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/delete01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in Set class. Use SvelteSet instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/delete01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/delete01-input.svelte
new file mode 100644
index 000000000..47221e97e
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set/delete01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new Set([1, 2, 1, 3, 3]);
+
+  variable.delete(42);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/_requirements.json b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/_requirements.json
new file mode 100644
index 000000000..498661308
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/_requirements.json
@@ -0,0 +1,3 @@
+{
+	"svelte": ">=5.0.0"
+}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/append01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/append01-errors.yaml
new file mode 100644
index 000000000..74c3a6f30
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/append01-errors.yaml
@@ -0,0 +1,5 @@
+- message: Found a mutable instance of the built-in URLSearchParams class. Use
+    SvelteURLSearchParams instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/append01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/append01-input.svelte
new file mode 100644
index 000000000..b42d06b7f
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/append01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URLSearchParams("foo=1&bar=2");
+
+  variable.append("baz", "3");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete01-errors.yaml
new file mode 100644
index 000000000..74c3a6f30
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete01-errors.yaml
@@ -0,0 +1,5 @@
+- message: Found a mutable instance of the built-in URLSearchParams class. Use
+    SvelteURLSearchParams instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete01-input.svelte
new file mode 100644
index 000000000..9c9f83cb3
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URLSearchParams("foo=1&bar=2");
+
+  variable.delete("foo");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete02-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete02-errors.yaml
new file mode 100644
index 000000000..74c3a6f30
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete02-errors.yaml
@@ -0,0 +1,5 @@
+- message: Found a mutable instance of the built-in URLSearchParams class. Use
+    SvelteURLSearchParams instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete02-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete02-input.svelte
new file mode 100644
index 000000000..2985e1c5b
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/delete02-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URLSearchParams("foo=1&bar=2");
+
+  variable.delete("bar", "42");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/set01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/set01-errors.yaml
new file mode 100644
index 000000000..74c3a6f30
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/set01-errors.yaml
@@ -0,0 +1,5 @@
+- message: Found a mutable instance of the built-in URLSearchParams class. Use
+    SvelteURLSearchParams instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/set01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/set01-input.svelte
new file mode 100644
index 000000000..cdc914757
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/set01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URLSearchParams("foo=1&bar=2");
+
+  variable.set("foo", "-1")
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/sort01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/sort01-errors.yaml
new file mode 100644
index 000000000..74c3a6f30
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/sort01-errors.yaml
@@ -0,0 +1,5 @@
+- message: Found a mutable instance of the built-in URLSearchParams class. Use
+    SvelteURLSearchParams instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/sort01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/sort01-input.svelte
new file mode 100644
index 000000000..58238d557
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params/sort01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URLSearchParams("foo=1&bar=2");
+
+  variable.sort();
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/_requirements.json b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/_requirements.json
new file mode 100644
index 000000000..498661308
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/_requirements.json
@@ -0,0 +1,3 @@
+{
+	"svelte": ">=5.0.0"
+}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hash01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hash01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hash01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hash01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hash01-input.svelte
new file mode 100644
index 000000000..7e3c2abd0
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hash01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.hash = "anchor";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/host01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/host01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/host01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/host01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/host01-input.svelte
new file mode 100644
index 000000000..dd40a07cb
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/host01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.host = "example.test";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hostname01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hostname01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hostname01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hostname01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hostname01-input.svelte
new file mode 100644
index 000000000..35328b235
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/hostname01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.hostname = "example.test";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/href01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/href01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/href01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/href01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/href01-input.svelte
new file mode 100644
index 000000000..b7c427074
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/href01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.href = "https://svelte.dev/";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/password01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/password01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/password01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/password01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/password01-input.svelte
new file mode 100644
index 000000000..ad5c5efcf
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/password01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.password = "passwd";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/pathname01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/pathname01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/pathname01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/pathname01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/pathname01-input.svelte
new file mode 100644
index 000000000..a047b2c66
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/pathname01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.pathname = "tutorial";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/port01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/port01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/port01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/port01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/port01-input.svelte
new file mode 100644
index 000000000..6435e1d5d
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/port01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.port = "80";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/protocol01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/protocol01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/protocol01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/protocol01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/protocol01-input.svelte
new file mode 100644
index 000000000..d3e029eb4
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/protocol01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.protocol = "https";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/search01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/search01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/search01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/search01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/search01-input.svelte
new file mode 100644
index 000000000..b14b6b9c5
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/search01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.search = "foo=bar";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/username01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/username01-errors.yaml
new file mode 100644
index 000000000..a576570ef
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/username01-errors.yaml
@@ -0,0 +1,4 @@
+- message: Found a mutable instance of the built-in URL class. Use SvelteURL instead.
+  line: 2
+  column: 20
+  suggestions: null
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/username01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/username01-input.svelte
new file mode 100644
index 000000000..8f94e0389
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url/username01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+
+  variable.username = "usr";
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/_requirements.json b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/_requirements.json
new file mode 100644
index 000000000..498661308
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/_requirements.json
@@ -0,0 +1,3 @@
+{
+	"svelte": ">=5.0.0"
+}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-date01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-date01-input.svelte
new file mode 100644
index 000000000..0ab09e823
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-date01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteDate as Date } from "svelte/reactivity";
+
+  const variable = new Date(8.64e15);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-map01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-map01-input.svelte
new file mode 100644
index 000000000..5f431b8b1
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-map01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteMap as Map } from "svelte/reactivity";
+
+  const variable = new Map([[1, "one"], [2, "two"]]);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-set01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-set01-input.svelte
new file mode 100644
index 000000000..bf3379c3c
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-set01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteSet as Set } from "svelte/reactivity";
+
+  const variable = new Set([1, 2, 1, 3, 3]);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url-search-params01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url-search-params01-input.svelte
new file mode 100644
index 000000000..8d3d4d2d2
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url-search-params01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURLSearchParams as URLSearchParams } from "svelte/reactivity";
+
+  const variable = new URLSearchParams("foo=1&bar=2");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url01-input.svelte
new file mode 100644
index 000000000..ea960e9fd
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURL as URL } from "svelte/reactivity";
+
+  const variable = new URL("https://svelte.dev/");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/date01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/date01-input.svelte
new file mode 100644
index 000000000..7d801e5a6
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/date01-input.svelte
@@ -0,0 +1,40 @@
+<script>
+  const variable = new Date(8.64e15);
+
+	console.log(Date.now());
+	console.log(Date.parse("1970-01-01T00:00:00Z"));
+	console.log(Date.UTC(96, 1, 2, 3, 4, 5));
+	console.log(variable.getDate());
+	console.log(variable.getDay());
+	console.log(variable.getFullYear());
+	console.log(variable.getHours());
+	console.log(variable.getMilliseconds());
+	console.log(variable.getMinutes());
+	console.log(variable.getMonth());
+	console.log(variable.getSeconds());
+	console.log(variable.getTime());
+	console.log(variable.getTimezoneOffset());
+	console.log(variable.getUTCDate());
+	console.log(variable.getUTCDay());
+	console.log(variable.getUTCFullYear());
+	console.log(variable.getUTCHours());
+	console.log(variable.getUTCMilliseconds());
+	console.log(variable.getUTCMinutes());
+	console.log(variable.getUTCMonth());
+	console.log(variable.getUTCSeconds());
+	console.log(variable.getYear());
+	console.log(variable.toDateString());
+	console.log(variable.toISOString());
+	console.log(variable.toJSON());
+	console.log(variable.toLocaleDateString());
+	console.log(variable.toLocaleString());
+	console.log(variable.toLocaleTimeString());
+	console.log(variable.toString());
+	console.log(variable.toTemporalInstant());
+	console.log(variable.toTimeString());
+	console.log(variable.toUTCString());
+	console.log(variable.valueOf());
+	console.log(variable[Symbol.toPrimitive]("string"));
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/map01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/map01-input.svelte
new file mode 100644
index 000000000..593d30511
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/map01-input.svelte
@@ -0,0 +1,18 @@
+<script>
+	const variable = new Map([[1, "one"], [2, "two"]]);
+
+	console.log(Map.groupBy(variable, (element) => "group"));
+	console.log(Map[Symbol.species]);
+	console.log(variable.entries());
+	variable.forEach((value) => {
+		console.log(value);
+	});
+	console.log(variable.get(1));
+	console.log(variable.has(1));
+	console.log(variable.keys());
+	console.log(variable.values());
+	console.log(variable[Symbol.iterator]());
+	console.log(variable.size);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/set01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/set01-input.svelte
new file mode 100644
index 000000000..c08c6b13e
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/set01-input.svelte
@@ -0,0 +1,24 @@
+<script>
+	const variable = new Set([1, 2, 1, 3, 3]);
+	const other = new Set([1, 2]);
+
+	console.log(Set[Symbol.species]);
+	console.log(variable.difference(other));
+	console.log(variable.entries());
+	variable.forEach((value) => {
+		console.log(value);
+	});
+	console.log(variable.has(1));
+	console.log(variable.intersection(other));
+	console.log(variable.isDisjointFrom(other));
+	console.log(variable.isSubsetOf(other));
+	console.log(variable.isSupersetOf(other));
+	console.log(variable.keys());
+	console.log(variable.symmetricDifference(other));
+	console.log(variable.union(other));
+	console.log(variable.values());
+	console.log(variable[Symbol.iterator]());
+	console.log(variable.size);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-date01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-date01-input.svelte
new file mode 100644
index 000000000..911cb5461
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-date01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteDate } from "svelte/reactivity";
+
+  const variable = new SvelteDate(8.64e15);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-map01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-map01-input.svelte
new file mode 100644
index 000000000..43ff00a06
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-map01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteMap } from "svelte/reactivity";
+
+  const variable = new SvelteMap([[1, "one"], [2, "two"]]);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-set01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-set01-input.svelte
new file mode 100644
index 000000000..6c6728c53
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-set01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteSet } from "svelte/reactivity";
+
+  const variable = new SvelteSet([1, 2, 1, 3, 3]);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url-search-params01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url-search-params01-input.svelte
new file mode 100644
index 000000000..0f66db767
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url-search-params01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURLSearchParams } from "svelte/reactivity";
+
+  const variable = new SvelteURLSearchParams("foo=1&bar=2");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url01-input.svelte
new file mode 100644
index 000000000..014046937
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURL } from "svelte/reactivity";
+
+  const variable = new SvelteURL("https://svelte.dev/");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-date01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-date01-input.svelte
new file mode 100644
index 000000000..851db5e63
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-date01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { Date } from "package";
+
+  const variable = new Date(8.64e15);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-map01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-map01-input.svelte
new file mode 100644
index 000000000..32eab3dc7
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-map01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { Map } from "package";
+
+  const variable = new Map([[1, "one"], [2, "two"]]);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-set01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-set01-input.svelte
new file mode 100644
index 000000000..fc378f046
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-set01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { Set } from "package";
+
+  const variable = new Set([1, 2, 1, 3, 3]);
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url-search-params01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url-search-params01-input.svelte
new file mode 100644
index 000000000..de69ce09e
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url-search-params01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { URLSearchParams } from "package";
+
+  const variable = new URLSearchParams("foo=1&bar=2");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url01-input.svelte
new file mode 100644
index 000000000..eab451693
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url01-input.svelte
@@ -0,0 +1,7 @@
+<script>
+  import { URL } from "package";
+
+  const variable = new URL("https://svelte.dev/");
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/url-search-params01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/url-search-params01-input.svelte
new file mode 100644
index 000000000..c791d271b
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/url-search-params01-input.svelte
@@ -0,0 +1,19 @@
+<script>
+	const variable = new URLSearchParams("foo=1&bar=2");
+
+	console.log(variable.size);
+	console.log(variable.entries());
+	variable.forEach((value, key) => {
+		console.log(key);
+		console.log(value);
+	})
+	console.log(variable.get("foo"));
+	console.log(variable.getAll("foo"));
+	console.log(variable.has("foo"));
+	console.log(variable.has("foo", "1"));
+	console.log(variable.keys());
+	console.log(variable.toString());
+	console.log(variable.values());
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/url01-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/url01-input.svelte
new file mode 100644
index 000000000..af916bf93
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/url01-input.svelte
@@ -0,0 +1,26 @@
+<script>
+	const variable = new URL("https://svelte.dev/");
+
+	console.log(variable.hash);
+	console.log(variable.host);
+	console.log(variable.hostname);
+	console.log(variable.href);
+	console.log(variable.origin);
+	console.log(variable.password);
+	console.log(variable.pathname);
+	console.log(variable.port);
+	console.log(variable.protocol);
+	console.log(variable.search);
+	console.log(variable.searchParams);
+	console.log(variable.username);
+	let unused = 30;
+	unused = variable.port;
+	console.log(URL.canParse("https://svelte.dev/"));
+	objectURL = URL.createObjectURL(new MediaSource());
+	console.log(URL.parse("https://svelte.dev/"));
+	URL.revokeObjectURL(objectURL);
+	console.log(variable.toJSON());
+	console.log(variable.toString());
+</script>
+
+{variable}
diff --git a/packages/eslint-plugin-svelte/tests/src/rules/prefer-svelte-reactivity.ts b/packages/eslint-plugin-svelte/tests/src/rules/prefer-svelte-reactivity.ts
new file mode 100644
index 000000000..da146b317
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/src/rules/prefer-svelte-reactivity.ts
@@ -0,0 +1,12 @@
+import { RuleTester } from '../../utils/eslint-compat.js';
+import rule from '../../../src/rules/prefer-svelte-reactivity.js';
+import { loadTestCases } from '../../utils/utils.js';
+
+const tester = new RuleTester({
+	languageOptions: {
+		ecmaVersion: 2020,
+		sourceType: 'module'
+	}
+});
+
+tester.run('prefer-svelte-reactivity', rule as any, loadTestCases('prefer-svelte-reactivity'));