fix: allow `await` in `{@const }` in more blocks

.changeset/red-phones-brake.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: allow `await` in `{@const }` in more blocks

packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitBlock.js

@@ -37,7 +37,11 @@ export function AwaitBlock(node, context) {
 		const declarations = argument?.declarations ?? [];
 		const block = /** @type {BlockStatement} */ (then_context.visit(node.then, then_context.state));
 
-		then_block = b.arrow(args, b.block([...declarations, ...block.body]));
+		then_block = b.arrow(
+			args,
+			b.block([...declarations, ...block.body]),
+			node.then.metadata.has_await
+		);
 	}
 
 	if (node.catch) {
@@ -53,7 +57,11 @@ export function AwaitBlock(node, context) {
 			catch_context.visit(node.catch, catch_context.state)
 		);
 
-		catch_block = b.arrow(args, b.block([...declarations, ...block.body]));
+		catch_block = b.arrow(
+			args,
+			b.block([...declarations, ...block.body]),
+			node.catch.metadata.has_await
+		);
 	}
 
 	context.state.init.push(
@@ -63,7 +71,11 @@ export function AwaitBlock(node, context) {
 				context.state.node,
 				expression,
 				node.pending
-					? b.arrow([b.id('$$anchor')], /** @type {BlockStatement} */ (context.visit(node.pending)))
+					? b.arrow(
+							[b.id('$$anchor')],
+							/** @type {BlockStatement} */ (context.visit(node.pending)),
+							node.pending.metadata.has_await
+						)
 					: b.null,
 				then_block,
 				catch_block

packages/svelte/src/compiler/phases/3-transform/client/visitors/EachBlock.js

@@ -326,12 +326,16 @@ export function EachBlock(node, context) {
 		b.literal(flags),
 		thunk,
 		key_function,
-		b.arrow(render_args, b.block(declarations.concat(block.body)))
+		b.arrow(render_args, b.block(declarations.concat(block.body)), node.body.metadata.has_await)
 	];
 
 	if (node.fallback) {
 		args.push(
-			b.arrow([b.id('$$anchor')], /** @type {BlockStatement} */ (context.visit(node.fallback)))
+			b.arrow(
+				[b.id('$$anchor')],
+				/** @type {BlockStatement} */ (context.visit(node.fallback)),
+				node.fallback.metadata.has_await
+			)
 		);
 	}
 

packages/svelte/src/compiler/phases/3-transform/client/visitors/IfBlock.js

@@ -15,14 +15,21 @@ export function IfBlock(node, context) {
 	const consequent = /** @type {BlockStatement} */ (context.visit(node.consequent));
 	const consequent_id = b.id(context.state.scope.generate('consequent'));
 
-	statements.push(b.var(consequent_id, b.arrow([b.id('$$anchor')], consequent)));
+	statements.push(
+		b.var(
+			consequent_id,
+			b.arrow([b.id('$$anchor')], consequent, node.consequent.metadata.has_await)
+		)
+	);
 
 	let alternate_id;
 
 	if (node.alternate) {
 		const alternate = /** @type {BlockStatement} */ (context.visit(node.alternate));
 		alternate_id = b.id(context.state.scope.generate('alternate'));
-		statements.push(b.var(alternate_id, b.arrow([b.id('$$anchor')], alternate)));
+		statements.push(
+			b.var(alternate_id, b.arrow([b.id('$$anchor')], alternate, node.alternate.metadata.has_await))
+		);
 	}
 
 	const { has_await } = node.metadata.expression;

packages/svelte/src/compiler/phases/3-transform/client/visitors/KeyBlock.js

@@ -18,7 +18,12 @@ export function KeyBlock(node, context) {
 	const body = /** @type {Expression} */ (context.visit(node.fragment));
 
 	let statement = add_svelte_meta(
-		b.call('$.key', context.state.node, key, b.arrow([b.id('$$anchor')], body)),
+		b.call(
+			'$.key',
+			context.state.node,
+			key,
+			b.arrow([b.id('$$anchor')], body, node.fragment.metadata.has_await)
+		),
 		node,
 		'key'
 	);

packages/svelte/src/compiler/phases/3-transform/client/visitors/SvelteBoundary.js

@@ -86,7 +86,12 @@ export function SvelteBoundary(node, context) {
 	block.body.unshift(...const_tags);
 
 	const boundary = b.stmt(
-		b.call('$.boundary', context.state.node, props, b.arrow([b.id('$$anchor')], block))
+		b.call(
+			'$.boundary',
+			context.state.node,
+			props,
+			b.arrow([b.id('$$anchor')], block, node.fragment.metadata.has_await)
+		)
 	);
 
 	context.state.template.push_comment();