From aff885bcd1f24e21fa7240a5d483d4bd116ba837 Mon Sep 17 00:00:00 2001
From: Ivan Kochurkin <ivan.kochurkin@jetbrains.com>
Date: Sat, 20 Nov 2021 16:23:34 +0300
Subject: [PATCH] [FIR] Prevent potential exponent complexity in
 isValidTypeParameterFromOuterDeclaration

---
 .../org/jetbrains/kotlin/fir/resolve/DeclarationUtils.kt    | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/DeclarationUtils.kt b/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/DeclarationUtils.kt
index 19185eb6b1d..8f6043f25db 100644
--- a/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/DeclarationUtils.kt
+++ b/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/DeclarationUtils.kt
@@ -41,7 +41,13 @@ fun isValidTypeParameterFromOuterDeclaration(
         return true  // Extra check is required because of classDeclaration will be resolved later
     }
 
+    val visited = mutableSetOf<FirDeclaration>()
+
     fun containsTypeParameter(currentDeclaration: FirDeclaration?): Boolean {
+        if (currentDeclaration == null || !visited.add(currentDeclaration)) {
+            return false
+        }
+
         if (currentDeclaration is FirTypeParameterRefsOwner) {
             if (currentDeclaration.typeParameters.any { it.symbol == typeParameterSymbol }) {
                 return true