complain if named slots other than direct descendant of component

src/compiler/compile/nodes/Element.ts

@@ -278,7 +278,7 @@ export default class Element extends Node {
 	}
 
 	validate_attributes() {
-		const { component } = this;
+		const { component, parent } = this;
 
 		const attribute_map = new Map();
 
@@ -395,26 +395,20 @@ export default class Element extends Node {
 					component.slot_outlets.add(name);
 				}
 
-				let ancestor = this.parent;
-				do {
-					if (ancestor.type === 'InlineComponent') break;
-					if (ancestor.type === 'Element' && /-/.test(ancestor.name)) break;
-
-					if (ancestor.type === 'IfBlock' || ancestor.type === 'EachBlock') {
-						const type = ancestor.type === 'IfBlock' ? 'if' : 'each';
-						const message = `Cannot place slotted elements inside an ${type}-block`;
+				if (parent.type === 'IfBlock' || parent.type === 'EachBlock') {
+					const type = parent.type === 'IfBlock' ? 'if' : 'each';
+					const message = `Cannot place slotted elements inside an ${type}-block`;
 
-						component.error(attribute, {
-							code: `invalid-slotted-content`,
-							message
-						});
-					}
-				} while (ancestor = ancestor.parent);
+					component.error(attribute, {
+						code: `invalid-slotted-content`,
+						message
+					});
+				}
 
-				if (!ancestor) {
+				if (!(parent.type === 'InlineComponent' || (parent.type === 'Element' && /-/.test(parent.name)))) {
 					component.error(attribute, {
 						code: `invalid-slotted-content`,
-						message: `Element with a slot='...' attribute must be a descendant of a component or custom element`
+						message: `Element with a slot='...' attribute must be a direct descendant of a component or custom element`,
 					});
 				}
 			}

test/runtime/samples/component-slot-nested-error-2/Nested.svelte

@@ -0,0 +1 @@
+<slot name="slot2"></slot>

test/runtime/samples/component-slot-nested-error-2/_config.js

@@ -0,0 +1,3 @@
+export default {
+	error: [`Element with a slot='...' attribute must be a direct descendant of a component or custom element`]
+};

test/runtime/samples/component-slot-nested-error-2/main.svelte

@@ -0,0 +1,11 @@
+<script>
+  import Nested from "./Nested.svelte";
+</script>
+
+<Nested>
+  <div slot="slot1">
+    <div>
+      <div slot="slot2" />
+    </div>
+  </div>
+</Nested>

test/runtime/samples/component-slot-nested-error-3/Nested.svelte

@@ -0,0 +1 @@
+<slot name="slot2"></slot>

test/runtime/samples/component-slot-nested-error-3/_config.js

@@ -0,0 +1,3 @@
+export default {
+	error: [`Element with a slot='...' attribute must be a direct descendant of a component or custom element`]
+};

test/runtime/samples/component-slot-nested-error-3/main.svelte

@@ -0,0 +1,11 @@
+<script>
+  import Nested from "./Nested.svelte";
+</script>
+
+<Nested>
+  <div>
+    <div>
+      <div slot="slot2" />
+    </div>
+  </div>
+</Nested>

test/runtime/samples/component-slot-nested-error/Nested.svelte

@@ -0,0 +1 @@
+<slot name="slot2"></slot>

test/runtime/samples/component-slot-nested-error/_config.js

@@ -0,0 +1,3 @@
+export default {
+	error: [`Element with a slot='...' attribute must be a direct descendant of a component or custom element`]
+};

test/runtime/samples/component-slot-nested-error/main.svelte

@@ -0,0 +1,9 @@
+<script>
+  import Nested from "./Nested.svelte";
+</script>
+
+<Nested>
+  <div slot="slot1">
+    <div slot="slot2" />
+  </div>
+</Nested>

test/validator/samples/slot-attribute-invalid/errors.json

@@ -1,6 +1,6 @@
 [{
 	"code": "invalid-slotted-content",
-	"message": "Element with a slot='...' attribute must be a descendant of a component or custom element",
+	"message": "Element with a slot='...' attribute must be a direct descendant of a component or custom element",
 	"start": {
 		"line": 1,
 		"column": 5,