Support arrow functions returning by reference (ref #2523)

Author: gsherwood

src/Files/File.php

@@ -1935,7 +1935,9 @@ public function isReference($stackPtr)
  true
  );
 
- if ($this->tokens[$tokenBefore]['code'] === T_FUNCTION) {
+ if ($this->tokens[$tokenBefore]['code'] === T_FUNCTION
+ || $this->tokens[$tokenBefore]['code'] === T_FN
+ ) {
  // Function returns a reference.
  return true;
  }

src/Standards/Squiz/Tests/WhiteSpace/OperatorSpacingUnitTest.inc

@@ -265,6 +265,8 @@ $a = $a instanceof $b;
 $a = $a instanceof $b;
 $a = ($a)instanceof$b;
 
+fn&($x) => $x;
+
 // phpcs:set Squiz.WhiteSpace.OperatorSpacing ignoreSpacingBeforeAssignments false
 $a = 3;
 

src/Standards/Squiz/Tests/WhiteSpace/OperatorSpacingUnitTest.inc.fixed

@@ -259,6 +259,8 @@ $a = $a instanceof $b;
 $a = $a instanceof $b;
 $a = ($a) instanceof $b;
 
+fn&($x) => $x;
+
 // phpcs:set Squiz.WhiteSpace.OperatorSpacing ignoreSpacingBeforeAssignments false
 $a = 3;
 

src/Standards/Squiz/Tests/WhiteSpace/OperatorSpacingUnitTest.php

@@ -98,7 +98,7 @@ public function getErrorList($testFile='OperatorSpacingUnitTest.inc')
  246 => 1,
  265 => 2,
  266 => 2,
- 269 => 2,
+ 271 => 2,
  ];
  break;
  case 'OperatorSpacingUnitTest.js':

tests/Core/File/IsReferenceTest.inc

@@ -136,3 +136,6 @@ functionCall( $something , &new Foobar() );
 
 /* testUseByReference */
 $closure = function() use (&$var){};
+
+/* testArrowFunctionReturnByReference */
+fn&($x) => $x;

tests/Core/File/IsReferenceTest.php

@@ -224,6 +224,10 @@ public function dataIsReference()
  '/* testUseByReference */',
  true,
  ],
+ [
+ '/* testArrowFunctionReturnByReference */',
+ true,
+ ],
  ];
 
  }//end dataIsReference()