From d9ebab6b75e94a55e29bc5f683f9f143a2e9b4d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maximilian=20B=C3=B6sing?=
 <2189546+boesing@users.noreply.github.com>
Date: Sun, 27 Aug 2023 17:05:13 +0200
Subject: [PATCH] bugfix: prevent infinite-loop when resolving type-aliases
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The type-expander returns the same `intersection_type` in case something is not properly expandable. To avoid infinite-loop, we do explicitly verify that the expanded  alias is actually resolved

Signed-off-by: Maximilian Bösing <2189546+boesing@users.noreply.github.com>
---
 src/Psalm/Internal/Type/TypeParser.php | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/Psalm/Internal/Type/TypeParser.php b/src/Psalm/Internal/Type/TypeParser.php
index 35ca41aa2..840d8ea35 100644
--- a/src/Psalm/Internal/Type/TypeParser.php
+++ b/src/Psalm/Internal/Type/TypeParser.php
@@ -1629,9 +1629,7 @@ class TypeParser
                 continue;
             }
 
-            $modified = true;
-
-            $normalized_intersection_types[] = TypeExpander::expandAtomic(
+            $expanded_intersection_type = TypeExpander::expandAtomic(
                 $codebase,
                 $intersection_type,
                 null,
@@ -1644,6 +1642,9 @@ class TypeParser
                 true,
                 true,
             );
+
+            $modified = $expanded_intersection_type[0] !== $intersection_type;
+            $normalized_intersection_types[] = $expanded_intersection_type;
         }
 
         if ($modified === false) {