fix: ignore typescript abstract methods during code transformation (#15267)

.changeset/short-fireants-talk.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ignore typescript abstract methods

packages/svelte/src/compiler/phases/1-parse/remove_typescript_nodes.js

@@ -118,6 +118,12 @@ const visitors = {
 		delete node.implements;
 		return context.next();
 	},
+	MethodDefinition(node, context) {
+		if (node.abstract) {
+			return b.empty;
+		}
+		return context.next();
+	},
 	VariableDeclaration(node, context) {
 		if (node.declare) {
 			return b.empty;

packages/svelte/tests/runtime-runes/samples/typescript/main.svelte

@@ -22,6 +22,11 @@
 
 	class MyClass implements Hello {}
 
+	abstract class MyAbstractClass {
+		abstract x(): void;
+		y() {}
+	}
+
 	declare const declared_const: number;
 	declare function declared_fn(): void;
 	declare class declared_class {