From bd8df0e820cbad0adbd89300cc257b20ee799b32 Mon Sep 17 00:00:00 2001
From: Matt Brown <github@muglug.com>
Date: Wed, 13 Jan 2021 11:35:44 -0500
Subject: [PATCH] Fix #5001 - update variables after context after type change
 from empty

Empty is the invalid state, and some old logic here was causing a bug
---
 src/Psalm/Context.php    |  5 +----
 tests/Loop/WhileTest.php | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/src/Psalm/Context.php b/src/Psalm/Context.php
index de698bc26..f62616160 100644
--- a/src/Psalm/Context.php
+++ b/src/Psalm/Context.php
@@ -463,10 +463,7 @@ class Context
 
             $new_type = $new_vars_in_scope[$var_id];
 
-            if (!$this_type->isEmpty()
-                && !$new_type->isEmpty()
-                && !$this_type->equals($new_type)
-            ) {
+            if (!$this_type->equals($new_type)) {
                 $redefined_vars[$var_id] = $this_type;
             }
         }
diff --git a/tests/Loop/WhileTest.php b/tests/Loop/WhileTest.php
index e62686f64..5629a4a21 100644
--- a/tests/Loop/WhileTest.php
+++ b/tests/Loop/WhileTest.php
@@ -585,6 +585,44 @@ class WhileTest extends \Psalm\Tests\TestCase
                         }
                     }'
             ],
+            'ifNestedInsideLoop' => [
+                '<?php
+                    function analyse(): int {
+                        $state = 1;
+
+                        while (rand(0, 1)) {
+                            if ($state === 3) {
+                                echo "here";
+                            } elseif ($state === 2) {
+                                if (rand(0, 1)) {
+                                    $state = 3;
+                                }
+                            } else {
+                                $state = 2;
+                            }
+                        }
+
+                        return $state;
+                    }'
+            ],
+            'ifNotNestedInsideLoop' => [
+                '<?php
+                    function analyse(): int {
+                        $state = 1;
+
+                        while (rand(0, 1)) {
+                            if ($state === 3) {
+                                echo "here";
+                            } elseif ($state === 2) {
+                                $state = 3;
+                            } else {
+                                $state = 2;
+                            }
+                        }
+
+                        return $state;
+                    }'
+            ],
         ];
     }