Remove return.missing baseline and fix its issue

phpstan.neon.dist

@@ -76,7 +76,6 @@ includes:
 	- tests/phpstan/baselines/property.phpDocType.neon
 	- tests/phpstan/baselines/property.private.neon
 	- tests/phpstan/baselines/property.protected.neon
-	- tests/phpstan/baselines/return.missing.neon
 	- tests/phpstan/baselines/return.type.neon
 	- tests/phpstan/baselines/return.unusedType.neon
 	- tests/phpstan/baselines/smallerOrEqual.alwaysTrue.neon

src/wp-includes/class-wp-widget.php

@@ -138,7 +138,8 @@ public function update( $new_instance, $old_instance ) {
 	 * @since 2.8.0
 	 *
 	 * @param array $instance The settings for the particular instance of the widget.
-	 * @return string|null Default return is 'noform'. A subclass may opt to return null.
+	 * @return string|void Default return is 'noform'. A subclass which echoes its own
+	 *                     form returns nothing.
 	 */
 	public function form( $instance ) {
 		echo '<p class="no-options-widget">' . __( 'There are no options for this widget.' ) . '</p>';

src/wp-includes/general-template.php

@@ -1673,11 +1673,13 @@ function wp_title( $sep = '»', $display = true, $seplocation = '' ) {
 	$title = apply_filters( 'wp_title', $title, $sep, $seplocation );
 
 	// Send it out.
-	if ( $display ) {
-		echo $title;
-	} else {
+	if ( ! $display ) {
 		return $title;
 	}
+
+	echo $title;
+
+	return null;
 }
 
 /**
@@ -1712,11 +1714,14 @@ function single_post_title( $prefix = '', $display = true ) {
 	 * @param WP_Post $_post       The current post.
 	 */
 	$title = apply_filters( 'single_post_title', $_post->post_title, $_post );
-	if ( $display ) {
-		echo $prefix . $title;
-	} else {
+
+	if ( ! $display ) {
 		return $prefix . $title;
 	}
+
+	echo $prefix . $title;
+
+	return null;
 }
 
 /**
@@ -1753,11 +1758,13 @@ function post_type_archive_title( $prefix = '', $display = true ) {
 	 */
 	$title = apply_filters( 'post_type_archive_title', $post_type_obj->labels->name, $post_type );
 
-	if ( $display ) {
-		echo $prefix . $title;
-	} else {
+	if ( ! $display ) {
 		return $prefix . $title;
 	}
+
+	echo $prefix . $title;
+
+	return null;
 }
 
 /**
@@ -1849,11 +1856,13 @@ function single_term_title( $prefix = '', $display = true ) {
 		return null;
 	}
 
-	if ( $display ) {
-		echo $prefix . $term_name;
-	} else {
+	if ( ! $display ) {
 		return $prefix . $term_name;
 	}
+
+	echo $prefix . $term_name;
+
+	return null;
 }
 
 /**
@@ -2913,11 +2922,13 @@ function the_date( $format = '', $before = '', $after = '', $display = true ) {
 	 */
 	$the_date = apply_filters( 'the_date', $the_date, $format, $before, $after );
 
-	if ( $display ) {
-		echo $the_date;
-	} else {
+	if ( ! $display ) {
 		return $the_date;
 	}
+
+	echo $the_date;
+
+	return null;
 }
 
 /**
@@ -2981,11 +2992,13 @@ function the_modified_date( $format = '', $before = '', $after = '', $display =
 	 */
 	$the_modified_date = apply_filters( 'the_modified_date', $the_modified_date, $format, $before, $after );
 
-	if ( $display ) {
-		echo $the_modified_date;
-	} else {
+	if ( ! $display ) {
 		return $the_modified_date;
 	}
+
+	echo $the_modified_date;
+
+	return null;
 }
 
 /**

src/wp-includes/link-template.php

@@ -1164,11 +1164,13 @@ function edit_term_link( $link = '', $before = '', $after = '', $term = null, $d
 	 */
 	$link = $before . apply_filters( 'edit_term_link', $link, $term->term_id ) . $after;
 
-	if ( $display ) {
-		echo $link;
-	} else {
+	if ( ! $display ) {
 		return $link;
 	}
+
+	echo $link;
+
+	return null;
 }
 
 /**
@@ -2547,11 +2549,13 @@ function next_posts( $max_page = 0, $display = true ) {
 	$link   = get_next_posts_page_link( $max_page );
 	$output = $link ? esc_url( $link ) : '';
 
-	if ( $display ) {
-		echo $output;
-	} else {
+	if ( ! $display ) {
 		return $output;
 	}
+
+	echo $output;
+
+	return null;
 }
 
 /**
@@ -2657,11 +2661,13 @@ function previous_posts( $display = true ) {
 	$link   = get_previous_posts_page_link();
 	$output = $link ? esc_url( $link ) : '';
 
-	if ( $display ) {
-		echo $output;
-	} else {
+	if ( ! $display ) {
 		return $output;
 	}
+
+	echo $output;
+
+	return null;
 }
 
 /**