Use regex to make the newer PHP syntax work in the older PHP Parser we're using.

README.md

@@ -23,6 +23,11 @@ After that install the dependencies using composer in the parser directory:
 composer install
 ```
 
+TEMPORARILY until the plugin supports the newer PHP syntax used within Core.
+```bash
+composer compat:munge
+```
+
 ## Running
 Activate the plugin first:
 

compat-reflector-munge.php

@@ -0,0 +1,20 @@
+<?php
+
+if ( ! file_exists( __DIR__ . '/vendor/phpdocumentor/reflection/src/phpDocumentor/Reflection/BaseReflector.php' ) ) {
+	echo "Run 'composer install' first.\n";
+	exit(1);
+}
+
+$contents = file_get_contents( __DIR__ . '/vendor/phpdocumentor/reflection/src/phpDocumentor/Reflection/BaseReflector.php' );
+
+$contents = preg_replace(
+	'/function getShortName().+?{/is',
+	'function getShortName() {
+		if ( method_exists( $this->node, "isAnonymous" ) && $this->node->isAnonymous() ) {
+		 	return "AnonymousClass";
+		}
+	',
+	$contents
+);
+
+file_put_contents( __DIR__ . '/vendor/phpdocumentor/reflection/src/phpDocumentor/Reflection/BaseReflector.php', $contents );

composer.json

@@ -36,7 +36,8 @@
 	"scripts"    : {
 		"test": "phpunit",
 		"test:watch": "phpunit-watcher watch < /dev/tty",
-		"test:coverage": "php -d xdebug.mode=coverage ./vendor/bin/phpunit --coverage-html coverage"
+		"test:coverage": "php -d xdebug.mode=coverage ./vendor/bin/phpunit --coverage-html coverage",
+		"compat:munge": "php compat-reflector-munge.php"
 	},
 	"autoload"   : {
 		"classmap": ["lib"],

lib/class-file-reflector.php

@@ -44,6 +44,82 @@ class File_Reflector extends FileReflector {
 	 */
 	protected $last_doc = null;
 
+	public function __construct( $file, $validate = false, $encoding = 'utf-8' ) {
+		parent::__construct( $file, false /* Force validation off */, $encoding );
+
+		// Nullable types are unknown to the parser, pretend they don't exist.
+		// The nullable type should be listed in the PHPDoc anyway.
+		$this->contents = preg_replace_callback(
+			'/(function [a-z0-9-_]+\([^{:]*?)\)(\:\s*\??\S+)?\s*[{;]/im',
+			static function( $m ) {
+				return preg_replace( '/\?(\S+)/', '$1', $m[0] ) ?: $m[0];
+			},
+			$this->contents
+		);
+
+		// Inline callables... ( $var )( $param ) can usualy be rewritten as $var( $param ).
+		$this->contents = preg_replace_callback(
+			'/(?:\s)(\(\s*\$[^()]+\))(\(.+\))/',
+			static function( $m ) {
+				return trim( $m[1], '() ' ) . trim( $m[2] );
+			},
+			$this->contents
+		);
+
+		// Short list() syntax...
+		$this->contents = preg_replace_callback(
+			'/(\s)\[(\s*\$[^();.*]{3,}?)\]\s*=/ism',
+			static function( $m ) {
+				return $m[1] . 'list( ' . $m[2] . ' ) =';
+			},
+			$this->contents
+		);
+
+		// Visibility on constants
+		$this->contents = preg_replace_callback(
+			'/\b(public|protected|private)\s+const\s+/im',
+			static function( $m ) {
+				return 'const ';
+			},
+			$this->contents
+		);
+
+		// constant arrays weren't supported.
+		$this->contents = preg_replace_callback(
+			'/\b(?<!\$|\[)([A-Z_]{5,})\[ ([^]]+)\]/',
+			function( $m ) {
+				return '$' . $m[1] . '[' . $m[2] . ']';
+			},
+			$this->contents
+		);
+
+		// Static calls on static calls. Mostly in tests.
+		$this->contents = preg_replace_callback(
+			'/([\$\[\]_a-z]+)::([\$\[\]_a-z]+)::([\$\[\]_a-z]+)/',
+			static function( $m ) {
+				//var_dump( $m );
+				if ( 'self' === $m[1] || 'static' === $m[1] ) {
+					return '$this->' . $m[2] . '->' . $m[3];
+				}
+
+				return $m[1] . '->' . $m[2]. '->' . $m[3];
+			},
+			$this->contents
+		);
+
+		// Static calls on function results. Mostly in tests.
+		$this->contents = preg_replace_callback(
+			'/([a-z_])\(\)::/',
+			static function( $m ) {
+				return $m[1] . '()->';
+			},
+			$this->contents
+		);
+
+		// Recalculate the hash, since we probably changed the contents.
+		$this->hash = md5($this->contents);
+	}
+
 	/**
 	 * Add hooks to the queue and update the node stack when we enter a node.
 	 *