Merge branch 'gh-2843' of https://github.com/IlyaSemenov/svelte into IlyaSemenov-gh-2843

Author: Rich-Harris

src/compiler/compile/index.ts

@@ -60,17 +60,25 @@ function get_name(filename: string) {
 	// eslint-disable-next-line no-useless-escape
 	const parts = filename.split(/[\/\\]/);
 
-	if (parts.length > 1 && /^index\.\w+/.test(parts[parts.length - 1])) {
-		parts.pop();
+	if (parts.length > 1) {
+		const index_match = parts[parts.length - 1].match(/^index(\.\w+)/);
+		if (index_match) {
+			parts.pop();
+			parts[parts.length - 1] += index_match[1];
+		}
 	}
 
 	const base = parts.pop()
-		.replace(/\..+/, "")
+		.replace(/\.[^.]+$/, "")
 		.replace(/[^a-zA-Z_$0-9]+/g, '_')
 		.replace(/^_/, '')
 		.replace(/_$/, '')
 		.replace(/^(\d)/, '_$1');
 
+	if (!base) {
+		throw new Error(`Could not derive component name from file ${filename}`);
+	}
+
 	return base[0].toUpperCase() + base.slice(1);
 }