parse <slot> as element in custom element mode

src/parse/index.ts

@@ -11,6 +11,7 @@ import error from '../utils/error';
 interface ParserOptions {
 	filename?: string;
 	bind?: boolean;
+	customElement?: boolean;
 }
 
 type ParserState = (parser: Parser) => (ParserState | void);
@@ -18,6 +19,7 @@ type ParserState = (parser: Parser) => (ParserState | void);
 export class Parser {
 	readonly template: string;
 	readonly filename?: string;
+	readonly customElement: boolean;
 
 	index: number;
 	stack: Array<Node>;
@@ -36,6 +38,7 @@ export class Parser {
 
 		this.template = template.replace(/\s+$/, '');
 		this.filename = options.filename;
+		this.customElement = options.customElement;
 
 		this.allowBindings = options.bind !== false;
 

src/parse/state/tag.ts

@@ -125,7 +125,7 @@ export default function tag(parser: Parser) {
 		? metaTags.get(name)
 		: (/[A-Z]/.test(name[0]) || name === 'svelte:self' || name === 'svelte:component') ? 'Component'
 		: name === 'title' && parentIsHead(parser.stack) ? 'Title'
-		: name === 'slot' ? 'Slot' : 'Element';
+		: name === 'slot' && !parser.customElement ? 'Slot' : 'Element';
 
 	const element: Node = {
 		start,

src/validate/html/validateComponent.ts

@@ -11,7 +11,7 @@ export default function validateComponent(
 	stack: Node[],
 	elementStack: Node[]
 ) {
-	if (!validator.components.has(node.name)) {
+	if (node.name !== 'svelte:self' && node.name !== 'svelte:component' && !validator.components.has(node.name)) {
 		validator.error(node, {
 			code: `missing-component`,
 			message: `${node.name} component is not defined`