[clang] [ThreadSafety] Fix C++20 build (PR #212042)

[Benjamin Kramer via cfe-commits]

https://github.com/d0k created https://github.com/llvm/llvm-project/pull/212042

In C++20 (P1008R1 https://wg21.link/p1008r1), aggregates are prohibited from having any user-declared constructors, even if they are = delete or = default.

>From 59adcfcd59b0335abcababb0570d0263c10825f8 Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra at googlemail.com>
Date: Sat, 25 Jul 2026 19:19:29 +0200
Subject: [PATCH] [ThreadSafety] Fix C++20 build

In C++20 (P1008R1 https://wg21.link/p1008r1), aggregates are prohibited
from having any user-declared constructors, even if they are = delete or
= default.
---
 clang/lib/Analysis/ThreadSafety.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Analysis/ThreadSafety.cpp b/clang/lib/Analysis/ThreadSafety.cpp
index 2b394865c5a5e..fe94910e905a3 100644
--- a/clang/lib/Analysis/ThreadSafety.cpp
+++ b/clang/lib/Analysis/ThreadSafety.cpp
@@ -1802,9 +1802,13 @@ class BuildLockset : public ConstStmtVisitor<BuildLockset> {
   public:
     enum Point : char { Pre = 0, Post = 1 };
 
-    struct ContextSwitchScope {
+    class ContextSwitchScope {
       DualLocalVarContext &DC;
       Point LastPoint;
+
+    public:
+      ContextSwitchScope(DualLocalVarContext &DC, Point LastPoint)
+          : DC(DC), LastPoint(LastPoint) {}
       ContextSwitchScope(const ContextSwitchScope &) = delete;
       ContextSwitchScope &operator=(const ContextSwitchScope &) = delete;
       ~ContextSwitchScope() { DC.switchContextTo(LastPoint); }
@@ -1814,7 +1818,7 @@ class BuildLockset : public ConstStmtVisitor<BuildLockset> {
     [[nodiscard]] ContextSwitchScope switchToContextForScope(Point P) {
       Point PriorPoint = CurrPoint;
       switchContextTo(P);
-      return ContextSwitchScope{*this, PriorPoint};
+      return ContextSwitchScope(*this, PriorPoint);
     }
 
     /// Update the pre- and post-contexts to be associated with the next Stmt \p