From 46dbd19afb79c5c81ccb87cee9e41ad668b35324 Mon Sep 17 00:00:00 2001
From: Sam McCall <sam.mccall@gmail.com>
Date: Mon, 21 Mar 2022 18:53:59 +0100
Subject: [PATCH] [clangd] Fix nullptr crash in AddUsing tweak on catch(...)

Fixes https://github.com/clangd/clangd/issues/1072
---
 clang-tools-extra/clangd/refactor/tweaks/AddUsing.cpp       |  2 ++
 clang-tools-extra/clangd/unittests/tweaks/AddUsingTests.cpp | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/clang-tools-extra/clangd/refactor/tweaks/AddUsing.cpp b/clang-tools-extra/clangd/refactor/tweaks/AddUsing.cpp
index a75c485..5a4e1aa 100644
--- a/clang-tools-extra/clangd/refactor/tweaks/AddUsing.cpp
+++ b/clang-tools-extra/clangd/refactor/tweaks/AddUsing.cpp
@@ -78,6 +78,8 @@ public:
   }
 
   bool TraverseDecl(Decl *Node) {
+    if (!Node)
+      return true;
     // There is no need to go deeper into nodes that do not enclose selection,
     // since "using" there will not affect selection, nor would it make a good
     // insertion point.
diff --git a/clang-tools-extra/clangd/unittests/tweaks/AddUsingTests.cpp b/clang-tools-extra/clangd/unittests/tweaks/AddUsingTests.cpp
index b9b5cf4..662000a 100644
--- a/clang-tools-extra/clangd/unittests/tweaks/AddUsingTests.cpp
+++ b/clang-tools-extra/clangd/unittests/tweaks/AddUsingTests.cpp
@@ -78,6 +78,19 @@ public:
   EXPECT_UNAVAILABLE(Header + "void fun() { one::two::f^f(); }");
 }
 
+TEST_F(AddUsingTest, Crash1072) {
+  // Used to crash when traversing catch(...)
+  // https://github.com/clangd/clangd/issues/1072
+  const char *Code = R"cpp(
+  namespace ns { class A; }
+  ns::^A *err;
+  void catchall() {
+    try {} catch(...) {}
+  }
+  )cpp";
+  EXPECT_AVAILABLE(Code);
+}
+
 TEST_F(AddUsingTest, Apply) {
   FileName = "test.cpp";
   struct {
-- 
2.7.4