From 3380de16a2ea0fb30218a14b4e0b0cc6a322fc7b Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Tue, 8 May 2018 23:17:11 -0400
Subject: [PATCH] Fix #709 - detect intersection template matches a bit better

---
 src/Psalm/Type/Union.php | 18 +++++++++++++++++-
 tests/TemplateTest.php   | 29 +++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/src/Psalm/Type/Union.php b/src/Psalm/Type/Union.php
index c58c2cddd..edcb4d351 100644
--- a/src/Psalm/Type/Union.php
+++ b/src/Psalm/Type/Union.php
@@ -601,10 +601,26 @@ class Union
                     $generic_params[$key]->setFromDocblock();
                 }
             } else {
+                $matching_atomic_type = null;
+
+                if ($input_type) {
+                    foreach ($input_type->types as $input_key => $atomic_input_type) {
+                        if ($input_key === $key) {
+                            $matching_atomic_type = $atomic_input_type;
+                            break;
+                        }
+
+                        if (strpos($input_key, $key . '&') === 0) {
+                            $matching_atomic_type = $atomic_input_type;
+                            break;
+                        }
+                    }
+                }
+
                 $atomic_type->replaceTemplateTypesWithStandins(
                     $template_types,
                     $generic_params,
-                    isset($input_type->types[$key]) ? $input_type->types[$key] : null
+                    $matching_atomic_type
                 );
             }
         }
diff --git a/tests/TemplateTest.php b/tests/TemplateTest.php
index 08275ed7a..9082545ee 100644
--- a/tests/TemplateTest.php
+++ b/tests/TemplateTest.php
@@ -471,6 +471,35 @@ class TemplateTest extends TestCase
                 ],
                 'error_levels' => ['MixedAssignment', 'MixedArgument'],
             ],
+            'intersectionTemplatedTypes' => [
+                '<?php
+                    namespace NS;
+                    use Countable;
+
+                    /** @template T */
+                    class Collection
+                    {
+                        /** @psalm-var iterable<T> */
+                        private $data;
+
+                        /** @psalm-param iterable<T> $data */
+                        public function __construct(iterable $data) {
+                            $this->data = $data;
+                        }
+                    }
+
+                    class Item {}
+                    /** @psalm-param Collection<Item> $c */
+                    function takesCollectionOfItems(Collection $c): void {}
+
+                    /** @psalm-var iterable<Item> $data2 */
+                    $data2 = [];
+                    takesCollectionOfItems(new Collection($data2));
+
+                    /** @psalm-var iterable<Item>&Countable $data */
+                    $data = [];
+                    takesCollectionOfItems(new Collection($data));',
+            ],
         ];
     }