Don't show 'Empty block' warnings for non-existent await branches

src/compile/nodes/CatchBlock.ts

@@ -15,6 +15,8 @@ export default class CatchBlock extends Node {
 		this.scope.add(parent.error, parent.expression.dependencies, this);
 		this.children = map_children(component, parent, this.scope, info.children);
 
+		if (!info.skip) {
 			this.warn_if_empty_block();
 		}
+	}
 }

src/compile/nodes/PendingBlock.ts

@@ -10,6 +10,8 @@ export default class PendingBlock extends Node {
 		super(component, parent, scope, info);
 		this.children = map_children(component, parent, scope, info.children);
 
+		if (!info.skip) {
 			this.warn_if_empty_block();
 		}
+	}
 }

src/compile/nodes/ThenBlock.ts

@@ -15,6 +15,8 @@ export default class ThenBlock extends Node {
 		this.scope.add(parent.value, parent.expression.dependencies, this);
 		this.children = map_children(component, parent, this.scope, info.children);
 
+		if (!info.skip) {
 			this.warn_if_empty_block();
 		}
+	}
 }

src/parse/state/mustache.ts

@@ -172,7 +172,8 @@ export default function mustache(parser: Parser) {
 				start,
 				end: null,
 				type: 'ThenBlock',
-				children: []
+				children: [],
+				skip: false
 			};
 
 			await_block.then = then_block;
@@ -196,7 +197,8 @@ export default function mustache(parser: Parser) {
 				start,
 				end: null,
 				type: 'CatchBlock',
-				children: []
+				children: [],
+				skip: false
 			};
 
 			await_block.catch = catch_block;
@@ -235,19 +237,22 @@ export default function mustache(parser: Parser) {
 					start: null,
 					end: null,
 					type: 'PendingBlock',
-					children: []
+					children: [],
+					skip: true
 				},
 				then: {
 					start: null,
 					end: null,
 					type: 'ThenBlock',
-					children: []
+					children: [],
+					skip: true
 				},
 				catch: {
 					start: null,
 					end: null,
 					type: 'CatchBlock',
-					children: []
+					children: [],
+					skip: true
 				},
 			} :
 			{
@@ -310,7 +315,15 @@ export default function mustache(parser: Parser) {
 		parser.stack.push(block);
 
 		if (type === 'AwaitBlock') {
-			const child_block = await_block_shorthand ? block.then : block.pending;
+			let child_block;
+			if (await_block_shorthand) {
+				block.then.skip = false;
+				child_block = block.then;
+			} else {
+				block.pending.skip = false;
+				child_block = block.pending;
+			}
+
 			child_block.start = parser.index;
 			parser.stack.push(child_block);
 		}

test/parser/samples/await-then-catch/output.json

@@ -19,6 +19,7 @@
 				"pending": {
 					"start": 19,
 					"end": 39,
+					"skip": false,
 					"type": "PendingBlock",
 					"children": [
 						{
@@ -53,6 +54,7 @@
 				"then": {
 					"start": 39,
 					"end": 88,
+					"skip": false,
 					"type": "ThenBlock",
 					"children": [
 						{
@@ -98,6 +100,7 @@
 				"catch": {
 					"start": 88,
 					"end": 140,
+					"skip": false,
 					"type": "CatchBlock",
 					"children": [
 						{

test/validator/samples/await-no-catch/input.svelte

@@ -0,0 +1,9 @@
+<script>
+	let promise;
+</script>
+
+{#await promise}
+	<p>Loading</p>
+{:then data}
+	<p>Data: {data}</p>
+{/await}

test/validator/samples/await-no-catch/warnings.json

@@ -0,0 +1 @@
+[]

test/validator/samples/await-shorthand-no-catch/input.svelte

@@ -0,0 +1,7 @@
+<script>
+	let promise;
+</script>
+
+{#await promise then data}
+	<p>Data: {data}</p>
+{/await}

test/validator/samples/await-shorthand-no-catch/warnings.json

@@ -0,0 +1 @@
+[]