allwpilib/upstream_utils/llvm_patches/0038-StringMap-fix-structured-bindings-with-move-only-typ.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Ryan Blue <ryanzblue@gmail.com>
Date: Tue, 24 Sep 2024 23:36:16 -0400
Subject: [PATCH 38/38] StringMap: fix structured bindings with move-only types

---
 llvm/include/llvm/ADT/StringMapEntry.h | 12 +++++++++++-
 llvm/unittests/ADT/StringMapTest.cpp   | 10 ++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/ADT/StringMapEntry.h b/llvm/include/llvm/ADT/StringMapEntry.h
index 011806f5fd89ff738ed805a82b3ddbc6fc9b08ce..5b8eeb167c53c7ab15d05b0c71b75cd7f5b496c5 100644
--- a/llvm/include/llvm/ADT/StringMapEntry.h
+++ b/llvm/include/llvm/ADT/StringMapEntry.h
@@ -159,7 +159,17 @@ decltype(auto) get(const StringMapEntry<ValueTy> &E) {
   if constexpr (Index == 0)
     return E.first();
   else
-    return E.second;
+    return (E.second);
+}
+
+// Allow structured bindings on StringMapEntry.
+template <std::size_t Index, typename ValueTy>
+decltype(auto) get(StringMapEntry<ValueTy> &E) {
+  static_assert(Index < 2);
+  if constexpr (Index == 0)
+    return E.first();
+  else
+    return (E.second);
 }
 
 } // end namespace llvm
diff --git a/llvm/unittests/ADT/StringMapTest.cpp b/llvm/unittests/ADT/StringMapTest.cpp
index 0d83669a580408e925ec6308410ebe7c01b48b12..f1834bec65afec6be4365e52c4e21aa61cbb1d12 100644
--- a/llvm/unittests/ADT/StringMapTest.cpp
+++ b/llvm/unittests/ADT/StringMapTest.cpp
@@ -526,6 +526,16 @@ TEST_F(StringMapTest, StructuredBindings) {
   }
 }
 
+TEST_F(StringMapTest, StructuredBindingsMoveOnly) {
+  StringMap<MoveOnly> A;
+  A.insert(std::make_pair("a", MoveOnly(42)));
+
+  for (auto &&[Key, Value] : A) {
+    EXPECT_EQ("a", Key);
+    EXPECT_EQ(42, Value.i);
+  }
+}
+
 namespace {
 // Simple class that counts how many moves and copy happens when growing a map
 struct CountCtorCopyAndMove {