tweak wording

Author: Rich-Harris

documentation/docs/98-reference/.generated/compile-errors.md

@@ -331,7 +331,7 @@ The $ prefix is reserved, and cannot be used for variables and imports
 ### each_item_invalid_assignment
 
 ```
-Cannot reassign or bind to the each block argument itself in runes mode. Use the array and index variables instead: For reassignments `array[i] = value` instead of `entry = value`, for bindings `bind:prop={array[i]}` instead of `bind:prop={value}`
+Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`, or `bind:value={array[i]}` instead of `bind:value={entry}`)
 ```
 
 In legacy mode, it was possible to reassign or bind to the each block argument itself:
@@ -344,23 +344,25 @@ In legacy mode, it was possible to reassign or bind to the each block argument i
 {#each array as entry}
 	<!-- reassignment -->
 	<button on:click={() => entry = 4}>change</button>
+
 	<!-- binding -->
 	<input bind:value={entry}>
 {/each}
 ```
 
-This is no longer possible in runes mode, because the array could also be a computed value such as `{#each array.filter((i) => i % 2)}`, at which point things get unstable. Svelte therefore requires you to be explicit about what to bind to, requiring a stable reference. Therefore, use the array and index variables instead:
+This turned out to be buggy and unpredictable, particularly when working with derived values (such as `array.map(...)`), and as such is forbidden in runes mode. You can achieve the same outcome by using the index instead:
 
 ```svelte
 <script>
 	let array = $state([1, 2, 3]);
 </script>
 
-{#each array as entry, idx}
+{#each array as entry, i}
 	<!-- reassignment -->
-	<button onclick={() => array[idx] = 4}>change</button>
+	<button onclick={() => array[i] = 4}>change</button>
+
 	<!-- binding -->
-	<input bind:value={array[idx]}>
+	<input bind:value={array[i]}>
 {/each}
 ```
 

packages/svelte/messages/compile-errors/script.md

@@ -32,7 +32,7 @@
 
 ## each_item_invalid_assignment
 
-> Cannot reassign or bind to the each block argument itself in runes mode. Use the array and index variables instead: For reassignments `array[i] = value` instead of `entry = value`, for bindings `bind:prop={array[i]}` instead of `bind:prop={value}`
+> Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`, or `bind:value={array[i]}` instead of `bind:value={entry}`)
 
 In legacy mode, it was possible to reassign or bind to the each block argument itself:
 
@@ -44,23 +44,25 @@ In legacy mode, it was possible to reassign or bind to the each block argument i
 {#each array as entry}
 	<!-- reassignment -->
 	<button on:click={() => entry = 4}>change</button>
+
 	<!-- binding -->
 	<input bind:value={entry}>
 {/each}
 ```
 
-This is no longer possible in runes mode, because the array could also be a computed value such as `{#each array.filter((i) => i % 2)}`, at which point things get unstable. Svelte therefore requires you to be explicit about what to bind to, requiring a stable reference. Therefore, use the array and index variables instead:
+This turned out to be buggy and unpredictable, particularly when working with derived values (such as `array.map(...)`), and as such is forbidden in runes mode. You can achieve the same outcome by using the index instead:
 
 ```svelte
 <script>
 	let array = $state([1, 2, 3]);
 </script>
 
-{#each array as entry, idx}
+{#each array as entry, i}
 	<!-- reassignment -->
-	<button onclick={() => array[idx] = 4}>change</button>
+	<button onclick={() => array[i] = 4}>change</button>
+
 	<!-- binding -->
-	<input bind:value={array[idx]}>
+	<input bind:value={array[i]}>
 {/each}
 ```
 

packages/svelte/src/compiler/errors.js

@@ -151,12 +151,12 @@ export function dollar_prefix_invalid(node) {
 }
 
 /**
- * Cannot reassign or bind to the each block argument itself in runes mode. Use the array and index variables instead: For reassignments `array[i] = value` instead of `entry = value`, for bindings `bind:prop={array[i]}` instead of `bind:prop={value}`
+ * Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`, or `bind:value={array[i]}` instead of `bind:value={entry}`)
  * @param {null | number | NodeLike} node
  * @returns {never}
  */
 export function each_item_invalid_assignment(node) {
-	e(node, "each_item_invalid_assignment", `Cannot reassign or bind to the each block argument itself in runes mode. Use the array and index variables instead: For reassignments \`array[i] = value\` instead of \`entry = value\`, for bindings \`bind:prop={array[i]}\` instead of \`bind:prop={value}\`\nhttps://svelte.dev/e/each_item_invalid_assignment`);
+	e(node, "each_item_invalid_assignment", `Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. \`array[i] = value\` instead of \`entry = value\`, or \`bind:value={array[i]}\` instead of \`bind:value={entry}\`)\nhttps://svelte.dev/e/each_item_invalid_assignment`);
 }
 
 /**

packages/svelte/tests/compiler-errors/samples/runes-invalid-each-binding-this/_config.js

@@ -4,6 +4,6 @@ export default test({
 	error: {
 		code: 'each_item_invalid_assignment',
 		message:
-			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`)'
+			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`, or `bind:value={array[i]}` instead of `bind:value={entry}`)'
 	}
 });

packages/svelte/tests/compiler-errors/samples/runes-invalid-each-binding/_config.js

@@ -4,6 +4,6 @@ export default test({
 	error: {
 		code: 'each_item_invalid_assignment',
 		message:
-			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`)'
+			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`, or `bind:value={array[i]}` instead of `bind:value={entry}`)'
 	}
 });

packages/svelte/tests/compiler-errors/samples/runes-invalid-each-mutation/_config.js

@@ -4,6 +4,6 @@ export default test({
 	error: {
 		code: 'each_item_invalid_assignment',
 		message:
-			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`)'
+			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`, or `bind:value={array[i]}` instead of `bind:value={entry}`)'
 	}
 });