From 5caa190a922e6baf9c2119f350d74ec22cf7dba8 Mon Sep 17 00:00:00 2001
From: zhscn <zhangsong325@gmail.com>
Date: Sun, 9 Nov 2025 11:51:45 +0800
Subject: [PATCH] indexer: Resolve the type alias correctly (#988)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The struct derived from an alias is missing from type hierarchy before this fix:
```cpp
struct Base {};
struct Derived : Base {};
using BaseAlias = Base;
struct DerivedAlias : BaseAlias {};
```
```
Derive from
Base
└╸Derived
```
The expected output is:
```
Derive from
Base
├╸Derived
└╸DerivedAlias
```
---
 src/indexer.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/indexer.cc b/src/indexer.cc
index c42fdd5f..c7e1752b 100644
--- a/src/indexer.cc
+++ b/src/indexer.cc
@@ -325,6 +325,9 @@ try_again:
   switch (tp->getTypeClass()) {
   case Type::Typedef:
     d = cast<TypedefType>(tp)->getDecl();
+    tp = cast<TypedefType>(tp)->getDecl()->getUnderlyingType().getTypePtrOrNull();
+    if (tp)
+      goto try_again;
     break;
   case Type::ObjCObject:
     d = cast<ObjCObjectType>(tp)->getInterface();