WordPress at a glance
filter is not described

woocommerce_checkout_must_be_logged_in_message filter-hook . WC 1.0

If checkout registration is disabled and not logged in, the user cannot checkout.

Usage

add_filter( 'woocommerce_checkout_must_be_logged_in_message', 'filter_function_name_2109' );
function filter_function_name_2109( $__ ){
	// filter...

	return $__;
}
$__
-

Where the hook is called

In file: /templates/checkout/form-checkout.php
woocommerce_checkout_must_be_logged_in_message
woocommerce/templates/checkout/form-checkout.php 26
echo esc_html( apply_filters( 'woocommerce_checkout_must_be_logged_in_message', __( 'You must be logged in to checkout.', 'woocommerce' ) ) );

Where in WP core the hook is used WooCommerce

Usage not found.