The double arrow inside arrow functions is now tokenized as T_FN_ARROW (ref #2523)

The reduces a lot of confusion with double arrows used in arrays.

Author: gsherwood

package.xml

@@ -28,7 +28,7 @@ http://pear.php.net/dtd/package-2.0.xsd">
  <notes>
   - The PHP 7.4 T_FN token has been made available for older versions
     -- T_FN represents the fn string used for arrow functions
-    -- The double arrow becomes the scope opener
+    -- The double arrow becomes the scope opener, and uses a new T_FN_ARROW token type
     -- The token after the statement (normally a semicolon) becomes the scope closer
     -- The token is also associated with the opening and closing parenthesis of the statement
     -- Any functions named "fn" will cause have a T_FN token for the function name, but have no scope information

src/Files/File.php

@@ -1654,7 +1654,7 @@ public function getMethodProperties($stackPtr)
             }
 
             if ($this->tokens[$stackPtr]['code'] === T_FN) {
-                $bodyToken = T_DOUBLE_ARROW;
+                $bodyToken = T_FN_ARROW;
             } else {
                 $bodyToken = T_OPEN_CURLY_BRACKET;
             }

src/Standards/Squiz/Tests/Arrays/ArrayDeclarationUnitTest.1.inc

@@ -410,6 +410,14 @@ $foo = array(<<<JSON
 JSON
        );
 
+$array = array(
+          'a'   => fn() => return 1,
+          'bb'  => fn() => return 2,
+          'ccc' => ( true ) ?
+              fn() => return 1 :
+              fn() => return 2,
+         );
+
 // Intentional syntax error.
 $a = array(
       'a' =>

src/Standards/Squiz/Tests/Arrays/ArrayDeclarationUnitTest.1.inc.fixed

@@ -438,6 +438,14 @@ $foo = array(<<<JSON
 JSON
        );
 
+$array = array(
+          'a'   => fn() => return 1,
+          'bb'  => fn() => return 2,
+          'ccc' => ( true ) ?
+              fn() => return 1 :
+              fn() => return 2,
+         );
+
 // Intentional syntax error.
 $a = array(
       'a' =>

src/Standards/Squiz/Tests/Arrays/ArrayDeclarationUnitTest.2.inc

@@ -399,6 +399,14 @@ $foo = [<<<JSON
 JSON
        ];
 
+$array = [
+          'a'   => fn() => return 1,
+          'bb'  => fn() => return 2,
+          'ccc' => ( true ) ?
+              fn() => return 1 :
+              fn() => return 2,
+         ];
+
 // Intentional syntax error.
 $a = [
       'a' =>

src/Standards/Squiz/Tests/Arrays/ArrayDeclarationUnitTest.2.inc.fixed

@@ -425,6 +425,14 @@ $foo = [<<<JSON
 JSON
        ];
 
+$array = [
+          'a'   => fn() => return 1,
+          'bb'  => fn() => return 2,
+          'ccc' => ( true ) ?
+              fn() => return 1 :
+              fn() => return 2,
+         ];
+
 // Intentional syntax error.
 $a = [
       'a' =>

src/Tokenizers/PHP.php

@@ -1704,6 +1704,9 @@ protected function processAdditional()
                             $this->tokens[$i]['parenthesis_opener'] = $x;
                             $this->tokens[$i]['parenthesis_closer'] = $this->tokens[$x]['parenthesis_closer'];
 
+                            $this->tokens[$arrow]['code'] = T_FN_ARROW;
+                            $this->tokens[$arrow]['type'] = 'T_FN_ARROW';
+
                             $this->tokens[$arrow]['scope_condition']       = $i;
                             $this->tokens[$arrow]['scope_opener']          = $arrow;
                             $this->tokens[$arrow]['scope_closer']          = $scopeCloser;

src/Util/Tokens.php

@@ -74,6 +74,7 @@
 define('T_CLOSE_USE_GROUP', 'PHPCS_T_CLOSE_USE_GROUP');
 define('T_ZSR', 'PHPCS_T_ZSR');
 define('T_ZSR_EQUAL', 'PHPCS_T_ZSR_EQUAL');
+define('T_FN_ARROW', 'T_FN_ARROW');
 
 // Some PHP 5.5 tokens, replicated for lower versions.
 if (defined('T_FINALLY') === false) {