Merge branch 'main' into missing-effects

Author: dummdidumm

.changeset/khaki-feet-teach.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ensure async deriveds always get dependencies from thennable

.changeset/metal-months-fail.md

@@ -196,6 +196,51 @@ Cyclical dependency detected: %cycle%
 `{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary` or `<Component>`
 ```
 
+### const_tag_invalid_reference
+
+```
+The `{@const %name% = ...}` declaration is not available in this snippet 
+```
+
+The following is an error:
+
+```svelte
+<svelte:boundary>
+    {@const foo = 'bar'}
+
+    {#snippet failed()}
+        {foo}
+    {/snippet}
+</svelte:boundary>
+```
+
+Here, `foo` is not available inside `failed`. The top level code inside `<svelte:boundary>` becomes part of the implicit `children` snippet, in other words the above code is equivalent to this:
+
+```svelte
+<svelte:boundary>
+    {#snippet children()}
+        {@const foo = 'bar'}
+    {/snippet}
+
+    {#snippet failed()}
+        {foo}
+    {/snippet}
+</svelte:boundary>
+```
+
+The same applies to components:
+
+```svelte
+<Component>
+    {@const foo = 'bar'}
+
+    {#snippet someProp()}
+        <!-- error -->
+        {foo}
+    {/snippet}
+</Component>
+```
+
 ### constant_assignment
 
 ```

.changeset/orange-chefs-float.md

@@ -1,5 +1,53 @@
 # svelte
 
+## 5.38.4
+
+### Patch Changes
+
+- fix: place instance-level snippets inside async body ([#16666](https://github.com/sveltejs/svelte/pull/16666))
+
+- fix: Add check for builtin custom elements in `set_custom_element_data` ([#16592](https://github.com/sveltejs/svelte/pull/16592))
+
+- fix: restore batch along with effect context ([#16668](https://github.com/sveltejs/svelte/pull/16668))
+
+- fix: wait until changes propagate before updating input selection state ([#16649](https://github.com/sveltejs/svelte/pull/16649))
+
+- fix: add "Accept-CH" as valid value for `http-equiv` ([#16671](https://github.com/sveltejs/svelte/pull/16671))
+
+## 5.38.3
+
+### Patch Changes
+
+- fix: ensure correct order of template effect values ([#16655](https://github.com/sveltejs/svelte/pull/16655))
+
+- fix: allow async `{@const}` in more places ([#16643](https://github.com/sveltejs/svelte/pull/16643))
+
+- fix: properly catch top level await errors ([#16619](https://github.com/sveltejs/svelte/pull/16619))
+
+- perf: prune effects without dependencies ([#16625](https://github.com/sveltejs/svelte/pull/16625))
+
+- fix: only emit `for_await_track_reactivity_loss` in async mode ([#16644](https://github.com/sveltejs/svelte/pull/16644))
+
+## 5.38.2
+
+### Patch Changes
+
+- perf: run blocks eagerly during flush instead of aborting ([#16631](https://github.com/sveltejs/svelte/pull/16631))
+
+- fix: don't clone non-proxies in `$inspect` ([#16617](https://github.com/sveltejs/svelte/pull/16617))
+
+- fix: avoid recursion error when tagging circular references ([#16622](https://github.com/sveltejs/svelte/pull/16622))
+
+## 5.38.1
+
+### Patch Changes
+
+- fix: wrap `abort` in `without_reactive_context` ([#16570](https://github.com/sveltejs/svelte/pull/16570))
+
+- fix: add `hint` as a possible value for `popover` attribute ([#16581](https://github.com/sveltejs/svelte/pull/16581))
+
+- fix: skip effects inside dynamic component that is about to be destroyed ([#16601](https://github.com/sveltejs/svelte/pull/16601))
+
 ## 5.38.0
 
 ### Minor Changes

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

@@ -1268,6 +1268,7 @@ export interface HTMLMetaAttributes extends HTMLAttributes<HTMLMetaElement> {
 	charset?: string | undefined | null;
 	content?: string | undefined | null;
 	'http-equiv'?:
+	  | 'accept-ch'
 		| 'content-security-policy'
 		| 'content-type'
 		| 'default-style'

packages/svelte/CHANGELOG.md

@@ -124,6 +124,49 @@
 
 > `{@const}` must be the immediate child of `{#snippet}`, `{#if}`, `{:else if}`, `{:else}`, `{#each}`, `{:then}`, `{:catch}`, `<svelte:fragment>`, `<svelte:boundary` or `<Component>`
 
+## const_tag_invalid_reference
+
+> The `{@const %name% = ...}` declaration is not available in this snippet 
+
+The following is an error:
+
+```svelte
+<svelte:boundary>
+    {@const foo = 'bar'}
+
+    {#snippet failed()}
+        {foo}
+    {/snippet}
+</svelte:boundary>
+```
+
+Here, `foo` is not available inside `failed`. The top level code inside `<svelte:boundary>` becomes part of the implicit `children` snippet, in other words the above code is equivalent to this:
+
+```svelte
+<svelte:boundary>
+    {#snippet children()}
+        {@const foo = 'bar'}
+    {/snippet}
+
+    {#snippet failed()}
+        {foo}
+    {/snippet}
+</svelte:boundary>
+```
+
+The same applies to components:
+
+```svelte
+<Component>
+    {@const foo = 'bar'}
+
+    {#snippet someProp()}
+        <!-- error -->
+        {foo}
+    {/snippet}
+</Component>
+```
+
 ## debug_tag_invalid_arguments
 
 > {@debug ...} arguments must be identifiers, not arbitrary expressions

packages/svelte/elements.d.ts

@@ -2,7 +2,7 @@
   "name": "svelte",
   "description": "Cybernetically enhanced web apps",
   "license": "MIT",
-  "version": "5.38.0",
+  "version": "5.38.4",
   "type": "module",
   "types": "./types/index.d.ts",
   "engines": {

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

@@ -985,6 +985,16 @@ export function const_tag_invalid_placement(node) {
 	e(node, 'const_tag_invalid_placement', `\`{@const}\` must be the immediate child of \`{#snippet}\`, \`{#if}\`, \`{:else if}\`, \`{:else}\`, \`{#each}\`, \`{:then}\`, \`{:catch}\`, \`<svelte:fragment>\`, \`<svelte:boundary\` or \`<Component>\`\nhttps://svelte.dev/e/const_tag_invalid_placement`);
 }
 
+/**
+ * The `{@const %name% = ...}` declaration is not available in this snippet 
+ * @param {null | number | NodeLike} node
+ * @param {string} name
+ * @returns {never}
+ */
+export function const_tag_invalid_reference(node, name) {
+	e(node, 'const_tag_invalid_reference', `The \`{@const ${name} = ...}\` declaration is not available in this snippet \nhttps://svelte.dev/e/const_tag_invalid_reference`);
+}
+
 /**
  * {@debug ...} arguments must be identifiers, not arbitrary expressions
  * @param {null | number | NodeLike} node

packages/svelte/package.json

@@ -7,6 +7,7 @@ import * as w from '../../../warnings.js';
 import { is_rune } from '../../../../utils.js';
 import { mark_subtree_dynamic } from './shared/fragment.js';
 import { get_rune } from '../../scope.js';
+import { is_component_node } from '../../nodes.js';
 
 /**
  * @param {Identifier} node
@@ -155,5 +156,37 @@ export function Identifier(node, context) {
 		) {
 			w.reactive_declaration_module_script_dependency(node);
 		}
+
+		if (binding.metadata?.is_template_declaration && context.state.options.experimental.async) {
+			let snippet_name;
+
+			// Find out if this references a {@const ...} declaration of an implicit children snippet
+			// when it is itself inside a snippet block at the same level. If so, error.
+			for (let i = context.path.length - 1; i >= 0; i--) {
+				const parent = context.path[i];
+				const grand_parent = context.path[i - 1];
+
+				if (parent.type === 'SnippetBlock') {
+					snippet_name = parent.expression.name;
+				} else if (
+					snippet_name &&
+					grand_parent &&
+					parent.type === 'Fragment' &&
+					(is_component_node(grand_parent) ||
+						(grand_parent.type === 'SvelteBoundary' &&
+							(snippet_name === 'failed' || snippet_name === 'pending')))
+				) {
+					if (
+						is_component_node(grand_parent)
+							? grand_parent.metadata.scopes.default === binding.scope
+							: context.state.scopes.get(parent) === binding.scope
+					) {
+						e.const_tag_invalid_reference(node, node.name);
+					} else {
+						break;
+					}
+				}
+			}
+		}
 	}
 }