Index: src/wp-includes/link-template.php
===================================================================
--- src/wp-includes/link-template.php	(revision 27810)
+++ src/wp-includes/link-template.php	(working copy)
@@ -1305,6 +1305,7 @@
 			'update_post_term_cache' => false,
 			'update_post_meta_cache' => false,
 			'split_the_query'        => wp_using_ext_object_cache(),
+			'fields'                 => 'ids',
 		);
 
 		$tax_query = array();
@@ -1375,7 +1376,8 @@
 		$query = new WP_Query( $query_args );
 
 		if ( $query->posts ) {
-			$this->adjacent_post = $query->post;
+			$post_id = reset( $query->posts );
+			$this->adjacent_post = get_post( $post_id );
 		} else {
 			$this->adjacent_post = false;
 		}