From 3a87f18b5a786a27c6e52bcf8df10418d6d7cdbe Mon Sep 17 00:00:00 2001
From: Matt Brown <github@muglug.com>
Date: Sat, 1 May 2021 20:00:01 -0400
Subject: [PATCH] Fix #5685 - properly negate complex conditionals

---
 src/Psalm/Type/Reconciler.php                 | 21 ++++++++++++++-----
 .../AssignmentInConditionalTest.php           |  7 +++++++
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/src/Psalm/Type/Reconciler.php b/src/Psalm/Type/Reconciler.php
index af775b7a3..b0a036b8a 100644
--- a/src/Psalm/Type/Reconciler.php
+++ b/src/Psalm/Type/Reconciler.php
@@ -160,9 +160,20 @@ class Reconciler
                 $orred_type = null;
 
                 foreach ($new_type_part_parts as $new_type_part_part) {
-                    if ($new_type_part_part[0] === '>') {
-                        /** @var array<string, array<int, array<int, string>>> */
-                        $data = \json_decode(substr($new_type_part_part, 1), true);
+                    if ($new_type_part_part[0] === '>'
+                        || ($new_type_part_part[0] === '!'
+                            && $new_type_part_part[1] === '>')
+                    ) {
+                        if ($new_type_part_part[0] === '!') {
+                            $nested_negated = !$negated;
+
+                            /** @var array<string, array<int, array<int, string>>> */
+                            $data = \json_decode(substr($new_type_part_part, 2), true);
+                        } else {
+                            $nested_negated = $negated;
+                            /** @var array<string, array<int, array<int, string>>> */
+                            $data = \json_decode(substr($new_type_part_part, 1), true);
+                        }
 
                         $existing_types = self::reconcileKeyedTypes(
                             $data,
@@ -174,10 +185,10 @@ class Reconciler
                             $template_type_map,
                             $inside_loop,
                             $code_location,
-                            $negated
+                            $nested_negated
                         );
 
-                        $new_type_part_part = '!falsy';
+                        $new_type_part_part = ($nested_negated ? '' : '!') . 'falsy';
                     }
 
                     $result_type_candidate = AssertionReconciler::reconcile(
diff --git a/tests/TypeReconciliation/AssignmentInConditionalTest.php b/tests/TypeReconciliation/AssignmentInConditionalTest.php
index 146c7be0b..dfe0aecf8 100644
--- a/tests/TypeReconciliation/AssignmentInConditionalTest.php
+++ b/tests/TypeReconciliation/AssignmentInConditionalTest.php
@@ -449,6 +449,13 @@ class AssignmentInConditionalTest extends \Psalm\Tests\TestCase
                 [],
                 '8.0'
             ],
+            'assignmentForComparison' => [
+                '<?php
+                    function foo(int $b): void {
+                        if ($a = $b > 1) {}
+                        if ($a) {}
+                    }'
+            ],
         ];
     }