From 72ce39ce0716c6aba157c2b33696965ba2c8d7a7 Mon Sep 17 00:00:00 2001
From: Gabor Horvath <gaborh@apple.com>
Date: Tue, 24 Sep 2024 12:01:26 +0100
Subject: [PATCH] [cxx-interop] Fix off-by-one error when importing
 lifetimebound attrs

---
 lib/ClangImporter/ImportDecl.cpp                        | 2 +-
 test/Interop/Cxx/class/nonescapable-lifetimebound.swift | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/ClangImporter/ImportDecl.cpp b/lib/ClangImporter/ImportDecl.cpp
index ae5d544f312d4..f907eaaf63457 100644
--- a/lib/ClangImporter/ImportDecl.cpp
+++ b/lib/ClangImporter/ImportDecl.cpp
@@ -3880,7 +3880,7 @@ namespace {
                 ? IndexSubset::get(Impl.SwiftContext,
                                    scopedLifetimeParamIndicesForReturn)
                 : nullptr,
-            swiftParams->size(),
+            swiftParams->size() + hasSelf,
             /*isImmortal*/ false));
       else if (auto *ctordecl = dyn_cast<clang::CXXConstructorDecl>(decl)) {
         // Assume default constructed view types have no dependencies.
diff --git a/test/Interop/Cxx/class/nonescapable-lifetimebound.swift b/test/Interop/Cxx/class/nonescapable-lifetimebound.swift
index d7841ca873b33..4afb28b7c5927 100644
--- a/test/Interop/Cxx/class/nonescapable-lifetimebound.swift
+++ b/test/Interop/Cxx/class/nonescapable-lifetimebound.swift
@@ -26,6 +26,10 @@ struct Owner {
     View handOutView() const [[clang::lifetimebound]] {
         return View(&data);
     }
+
+    View handOutView2(View v) const [[clang::lifetimebound]] {
+        return View(&data);
+    }
 };
 
 Owner makeOwner() {
@@ -69,6 +73,7 @@ private:
 // CHECK: sil [clang getViewFromFirst] {{.*}} : $@convention(c) (@in_guaranteed Owner, @in_guaranteed Owner) -> _scope(0) @autoreleased View
 // CHECK: sil [clang getViewFromEither] {{.*}} : $@convention(c) (@in_guaranteed Owner, @in_guaranteed Owner) -> _scope(0, 1) @autoreleased View
 // CHECK: sil [clang Owner.handOutView] {{.*}} : $@convention(cxx_method) (@in_guaranteed Owner) -> _scope(0) @autoreleased View
+// CHECK: sil [clang Owner.handOutView2] {{.*}} : $@convention(cxx_method) (View, @in_guaranteed Owner) -> _scope(1) @autoreleased View
 // CHECK: sil [clang getViewFromEither] {{.*}} : $@convention(c) (@guaranteed View, @guaranteed View) -> _inherit(0, 1) @autoreleased View
 // CHECK: sil [clang View.init] {{.*}} : $@convention(c) () -> @out View
 
@@ -83,6 +88,7 @@ public func test() {
     let v2 = getViewFromFirst(o, o2)
     let _ = getViewFromEither(o, o2)
     let _ = o.handOutView()
+    let _ = o.handOutView2(v1)
     let _ = getViewFromEither(v1, v2)
     let defaultView = View()
 }
\ No newline at end of file