From 99e5e19e72db30691a389d769bf4be2fa85f4dd1 Mon Sep 17 00:00:00 2001
From: Jelle <duckdoom5@users.noreply.github.com>
Date: Mon, 3 Feb 2025 21:58:03 +0000
Subject: [PATCH] Fix crash on nullptr `TemplateTypeParm` decl (#1901)

---
 src/CppParser/Parser.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/CppParser/Parser.cpp b/src/CppParser/Parser.cpp
index 3e80f3d0..467d8ca6 100644
--- a/src/CppParser/Parser.cpp
+++ b/src/CppParser/Parser.cpp
@@ -2868,9 +2868,13 @@ Type* Parser::WalkType(clang::QualType QualType, const clang::TypeLoc* TL,
             }
 
             assertm(TL->getTypeLocClass() == TypeLoc::TemplateTypeParm, "Token should be template type parameter!\n");
-            auto TTTL = TL->getAs<TemplateTypeParmTypeLoc>();
+            auto TTPTL = TL->getAs<TemplateTypeParmTypeLoc>();
+            auto TTPD = TTPTL.getDecl();
 
-            TPT->parameter = WalkTypeTemplateParameter(TTTL.getDecl());
+            if (!TTPD)
+                return nullptr; // Can happen when a template param is used in a nested template argument
+
+            TPT->parameter = WalkTypeTemplateParameter(TTPD);
         }
         else if (TP->getDecl())
             TPT->parameter = WalkTypeTemplateParameter(TP->getDecl());