From 391696bc839b82a440e39f5813b631c16c54c087 Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Sat, 16 Sep 2017 13:28:33 -0400
Subject: [PATCH] Use a blacklist, not a whitelist

---
 src/Psalm/Checker/Statements/Expression/CallChecker.php | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/Psalm/Checker/Statements/Expression/CallChecker.php b/src/Psalm/Checker/Statements/Expression/CallChecker.php
index 181e919aa..e9503f179 100644
--- a/src/Psalm/Checker/Statements/Expression/CallChecker.php
+++ b/src/Psalm/Checker/Statements/Expression/CallChecker.php
@@ -1704,8 +1704,12 @@ class CallChecker
 
             if ($function_param
                 && $function_param->by_ref
-                && !($arg->value instanceof PhpParser\Node\Expr\Variable)
-                && !($arg->value instanceof PhpParser\Node\Expr\PropertyFetch)
+                && ($arg->value instanceof PhpParser\Node\Scalar
+                    || $arg->value instanceof PhpParser\Node\Expr\ClassConstFetch
+                    || $arg->value instanceof PhpParser\Node\Expr\ConstFetch
+                    || $arg->value instanceof PhpParser\Node\Expr\FuncCall
+                    || $arg->value instanceof PhpParser\Node\Expr\MethodCall
+                )
             ) {
                 if (IssueBuffer::accepts(
                     new InvalidPassByReference(