Correctly mark pass-by-reference variables in use() constructs (#54)

* Test: add test for pass-by-reference in anonymous functions' use construct

* checkForFunctionPrototype: Mark relevant variables in use() constructs as pass-by-reference

Author: loilo

VariableAnalysis/Sniffs/CodeAnalysis/VariableAnalysisSniff.php

@@ -274,6 +274,14 @@ protected function checkForFunctionPrototype(File $phpcsFile, $stackPtr, $varNam
         // TODO: typeHints in use?
         $this->markVariableDeclaration($varName, 'bound', null, $stackPtr, $functionPtr);
         $this->markVariableAssignment($varName, $stackPtr, $functionPtr);
+
+        // Are we pass-by-reference?
+        $referencePtr = $phpcsFile->findPrevious(T_WHITESPACE, $stackPtr - 1, null, true, null, true);
+        if (($referencePtr !== false) && ($tokens[$referencePtr]['code'] === T_BITWISE_AND)) {
+          $varInfo = $this->getOrCreateVariableInfo($varName, $functionPtr);
+          $varInfo->passByReference = true;
+        }
+
         return true;
       }
     }

VariableAnalysis/Tests/CodeAnalysis/VariableAnalysisTest.php

@@ -37,6 +37,15 @@ public function testFunctionWithoutParamsWarnings() {
     $this->assertEquals($expectedWarnings, $lines);
   }
 
+  public function testFunctionWithUseReferenceWarnings() {
+    $fixtureFile = $this->getFixture('FunctionWithUseReferenceFixture.php');
+    $phpcsFile = $this->prepareLocalFileForSniffs($this->getSniffFiles(), $fixtureFile);
+    $phpcsFile->process();
+    $lines = $this->getWarningLineNumbersFromFile($phpcsFile);
+    $expectedErrors = [];
+    $this->assertEquals($expectedErrors, $lines);
+  }
+
   public function testFunctionWithDefaultParamErrors() {
     $fixtureFile = $this->getFixture('FunctionWithDefaultParamFixture.php');
     $phpcsFile = $this->prepareLocalFileForSniffs($this->getSniffFiles(), $fixtureFile);

VariableAnalysis/Tests/CodeAnalysis/fixtures/FunctionWithUseReferenceFixture.php

@@ -0,0 +1,7 @@
+<?php
+
+$ref = 0;
+
+$function_with_use_reference = function () use (&$ref) {
+    $ref = 1;
+};