From 837f5d7096d08304f5d58d3bc220e34cd7dfafef Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Tue, 20 Mar 2018 20:56:33 -0400
Subject: [PATCH] Fix #594 - support intersection types (and catch errors)

---
 src/Psalm/Checker/TypeChecker.php | 76 +++++++++++++++++--------------
 tests/TypeReconciliationTest.php  |  2 +-
 2 files changed, 43 insertions(+), 35 deletions(-)

diff --git a/src/Psalm/Checker/TypeChecker.php b/src/Psalm/Checker/TypeChecker.php
index 2a0181dab..eb544654c 100644
--- a/src/Psalm/Checker/TypeChecker.php
+++ b/src/Psalm/Checker/TypeChecker.php
@@ -216,45 +216,53 @@ class TypeChecker
     ) {
         $intersection_input_types = $input_type_part->extra_types ?: [];
         $intersection_input_types[] = $input_type_part;
-        $container_type_lower = strtolower($container_type_part->value);
 
-        foreach ($intersection_input_types as $intersection_input_type) {
-            if ($intersection_input_type->value === $container_type_part->value) {
-                return true;
+        $intersection_container_types = $container_type_part->extra_types ?: [];
+        $intersection_container_types[] = $container_type_part;
+
+        foreach ($intersection_container_types as $intersection_container_type) {
+            $intersection_container_type_lower = strtolower($intersection_container_type->value);
+
+            foreach ($intersection_input_types as $intersection_input_type) {
+                $intersection_input_type_lower = strtolower($intersection_input_type->value);
+
+                if ($intersection_container_type_lower === $intersection_input_type_lower) {
+                    continue 2;
+                }
+
+                if ($intersection_input_type_lower === 'generator'
+                    && in_array($intersection_container_type_lower, ['iterator', 'traversable', 'iterable'], true)
+                ) {
+                    continue 2;
+                }
+
+                if ($codebase->classExists($intersection_input_type->value)
+                    && $codebase->classExtendsOrImplements(
+                        $intersection_input_type->value,
+                        $intersection_container_type->value
+                    )
+                ) {
+                    continue 2;
+                }
+
+                if ($codebase->interfaceExists($intersection_input_type->value)
+                    && $codebase->interfaceExtends(
+                        $intersection_input_type->value,
+                        $intersection_container_type->value
+                    )
+                ) {
+                    continue 2;
+                }
+
+                if (ExpressionChecker::isMock($intersection_input_type->value)) {
+                    return true;
+                }
             }
 
-            $intersection_input_type_lower = strtolower($intersection_input_type->value);
-
-            if ($intersection_input_type_lower === 'generator'
-                && in_array($container_type_lower, ['iterator', 'traversable', 'iterable'], true)
-            ) {
-                return true;
-            }
-
-            if ($codebase->classExists($intersection_input_type->value)
-                && $codebase->classExtendsOrImplements(
-                    $intersection_input_type->value,
-                    $container_type_part->value
-                )
-            ) {
-                return true;
-            }
-
-            if ($codebase->interfaceExists($intersection_input_type->value)
-                && $codebase->interfaceExtends(
-                    $intersection_input_type->value,
-                    $container_type_part->value
-                )
-            ) {
-                return true;
-            }
-
-            if (ExpressionChecker::isMock($intersection_input_type->value)) {
-                return true;
-            }
+            return false;
         }
 
-        return false;
+        return true;
     }
 
     /**
diff --git a/tests/TypeReconciliationTest.php b/tests/TypeReconciliationTest.php
index b29c73f40..65866078b 100644
--- a/tests/TypeReconciliationTest.php
+++ b/tests/TypeReconciliationTest.php
@@ -838,7 +838,7 @@ class TypeReconciliationTest extends TestCase
                     }',
                 'error_message' => 'PossiblyInvalidArgument',
             ],
-            'SKIPPED-intersection' => [
+            'intersectionIncorrect' => [
                 '<?php
                     interface I {
                         public function bat(): void;