From 4a28525275829539f3a70b87fcb044e4c431028e Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Fri, 27 Dec 2019 13:01:44 -0500
Subject: [PATCH] Fix removal of traversable from iterable

Fixes #2509
---
 .../Internal/Type/NegatedAssertionReconciler.php   |  8 +++++---
 tests/TypeReconciliation/ConditionalTest.php       | 14 ++++++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/Psalm/Internal/Type/NegatedAssertionReconciler.php b/src/Psalm/Internal/Type/NegatedAssertionReconciler.php
index 21c9f3312..9a3f466bc 100644
--- a/src/Psalm/Internal/Type/NegatedAssertionReconciler.php
+++ b/src/Psalm/Internal/Type/NegatedAssertionReconciler.php
@@ -238,13 +238,15 @@ class NegatedAssertionReconciler extends Reconciler
         }
 
         if (strtolower($assertion) === 'traversable'
-            && isset($existing_var_type->getTypes()['iterable'])
+            && isset($existing_var_atomic_types['iterable'])
         ) {
+            /** @var Type\Atomic\TIterable */
+            $iterable = $existing_var_atomic_types['iterable'];
             $existing_var_type->removeType('iterable');
             $existing_var_type->addType(new TArray(
                 [
-                    new Type\Union([new TArrayKey]),
-                    new Type\Union([new TMixed]),
+                    $iterable->type_params[0],
+                    $iterable->type_params[1],
                 ]
             ));
         } elseif (strtolower($assertion) === 'int'
diff --git a/tests/TypeReconciliation/ConditionalTest.php b/tests/TypeReconciliation/ConditionalTest.php
index 7bbe333be..83d933014 100644
--- a/tests/TypeReconciliation/ConditionalTest.php
+++ b/tests/TypeReconciliation/ConditionalTest.php
@@ -2376,6 +2376,20 @@ class ConditionalTest extends \Psalm\Tests\TestCase
                         return $foo;
                     }'
             ],
+            'isNotTraversable' => [
+                '<?php
+                    /**
+                     * @psalm-param iterable<string> $collection
+                     * @psalm-return array<string>
+                     */
+                    function order(iterable $collection): array {
+                        if ($collection instanceof \Traversable) {
+                            $collection = iterator_to_array($collection, false);
+                        }
+
+                        return $collection;
+                    }'
+            ],
         ];
     }