fix: remove buggy validate_dynamic_component check (#12960)

closes #12857

Author: Rich-Harris

.changeset/young-peaches-agree.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: remove buggy `validate_dynamic_component` check

packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js

@@ -348,14 +348,7 @@ export function build_component(node, component_name, context, anchor = context.
 				b.thunk(/** @type {Expression} */ (context.visit(node.expression))),
 				b.arrow(
 					[b.id('$$anchor'), b.id(component_name)],
-					b.block([
-						...binding_initializers,
-						b.stmt(
-							dev
-								? b.call('$.validate_dynamic_component', b.thunk(prev(b.id('$$anchor'))))
-								: prev(b.id('$$anchor'))
-						)
-					])
+					b.block([...binding_initializers, b.stmt(prev(b.id('$$anchor')))])
 				)
 			);
 		};

packages/svelte/src/internal/client/index.js

@@ -144,12 +144,7 @@ export {
 	setContext,
 	hasContext
 } from './runtime.js';
-export {
-	validate_binding,
-	validate_dynamic_component,
-	validate_each_keys,
-	validate_prop_bindings
-} from './validate.js';
+export { validate_binding, validate_each_keys, validate_prop_bindings } from './validate.js';
 export { raf } from './timing.js';
 export { proxy } from './proxy.js';
 export { create_custom_element } from './dom/elements/custom-element.js';

packages/svelte/src/internal/client/validate.js

@@ -14,31 +14,6 @@ function is_void(tag) {
 	return void_element_names.test(tag) || tag.toLowerCase() === '!doctype';
 }
 
-/**
- * @template Component
- * @param {() => Component} component_fn
- * @returns {Component}
- */
-export function validate_dynamic_component(component_fn) {
-	try {
-		const instance = component_fn();
-
-		if (instance !== undefined && typeof instance !== 'object') {
-			e.svelte_component_invalid_this_value();
-		}
-
-		return instance;
-	} catch (err) {
-		const { message } = /** @type {Error} */ (err);
-
-		if (typeof message === 'string' && message.indexOf('is not a function') !== -1) {
-			e.svelte_component_invalid_this_value();
-		}
-
-		throw err;
-	}
-}
-
 /**
  * @param {() => any} collection
  * @param {(item: any, index: number) => string} key_fn