From dba429f1110b91fcbd3a7ee358edcac38d0c0209 Mon Sep 17 00:00:00 2001
From: Brian Bi <bbi10@bloomberg.net>
Date: Wed, 8 May 2024 15:58:12 -0400
Subject: [PATCH] Remove unevaluated lambdas from bsl::optional implementation
 (#4734)

---
 groups/bsl/bslstl/bslstl_optional.h       | 16 ++++++++++------
 groups/bsl/bslstl/bslstl_optional_cpp03.h | 18 +++++++++++-------
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/groups/bsl/bslstl/bslstl_optional.h b/groups/bsl/bslstl/bslstl_optional.h
index 45f53d81ad..36139cbb10 100644
--- a/groups/bsl/bslstl/bslstl_optional.h
+++ b/groups/bsl/bslstl/bslstl_optional.h
@@ -705,6 +705,12 @@ struct Optional_Data<TYPE, true> : public Optional_DataImp<TYPE> {
 namespace bsl {
 
 #ifdef BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS
+template <class t_TYPE>
+void optional_acceptsBslOptional(const bsl::optional<t_TYPE>&);
+
+template <class t_TYPE>
+void optional_acceptsStdOptional(const std::optional<t_TYPE>&);
+
 template <class t_TYPE>
 concept Optional_ConvertibleToBool =
     // This component-private concept models the Standard's exposition-only
@@ -715,16 +721,14 @@ template <class t_TYPE>
 concept Optional_DerivedFromBslOptional =
     // This component-private concept is used in the subsequent implementation
     // of the component-private concept 'Optional_DerivedFromOptional'.
-    requires(const t_TYPE &t) {
-        []<class U>(const bsl::optional<U>&){}(t);
-    };
+    requires (const t_TYPE& t) { optional_acceptsBslOptional(t); };
+
 template <class t_TYPE>
 concept Optional_DerivedFromStdOptional =
     // This component-private concept is used in the subsequent implementation
     // of the component-private concept 'Optional_DerivedFromOptional'.
-    requires(const t_TYPE &t) {
-        []<class U>(const std::optional<U>&){}(t);
-    };
+    requires (const t_TYPE& t) { optional_acceptsStdOptional(t); };
+
 template <class t_TYPE>
 concept Optional_DerivedFromOptional =
     // This component-private concept models whether a type is derived from one
diff --git a/groups/bsl/bslstl/bslstl_optional_cpp03.h b/groups/bsl/bslstl/bslstl_optional_cpp03.h
index bfb3dfb603..272bd30ecd 100644
--- a/groups/bsl/bslstl/bslstl_optional_cpp03.h
+++ b/groups/bsl/bslstl/bslstl_optional_cpp03.h
@@ -21,7 +21,7 @@
 // regions of C++11 code, then this header contains no code and is not
 // '#include'd in the original header.
 //
-// Generated on Thu Jan 11 05:07:56 2024
+// Generated on Wed May  8 14:37:33 2024
 // Command line: sim_cpp11_features.pl bslstl_optional.h
 
 #ifdef COMPILING_BSLSTL_OPTIONAL_H
@@ -904,6 +904,12 @@ struct Optional_Data<TYPE, true> : public Optional_DataImp<TYPE> {
 namespace bsl {
 
 #ifdef BSLS_LIBRARYFEATURES_HAS_CPP20_CONCEPTS
+template <class t_TYPE>
+void optional_acceptsBslOptional(const bsl::optional<t_TYPE>&);
+
+template <class t_TYPE>
+void optional_acceptsStdOptional(const std::optional<t_TYPE>&);
+
 template <class t_TYPE>
 concept Optional_ConvertibleToBool =
     // This component-private concept models the Standard's exposition-only
@@ -914,16 +920,14 @@ template <class t_TYPE>
 concept Optional_DerivedFromBslOptional =
     // This component-private concept is used in the subsequent implementation
     // of the component-private concept 'Optional_DerivedFromOptional'.
-    requires(const t_TYPE &t) {
-        []<class U>(const bsl::optional<U>&){}(t);
-    };
+    requires (const t_TYPE& t) { optional_acceptsBslOptional(t); };
+
 template <class t_TYPE>
 concept Optional_DerivedFromStdOptional =
     // This component-private concept is used in the subsequent implementation
     // of the component-private concept 'Optional_DerivedFromOptional'.
-    requires(const t_TYPE &t) {
-        []<class U>(const std::optional<U>&){}(t);
-    };
+    requires (const t_TYPE& t) { optional_acceptsStdOptional(t); };
+
 template <class t_TYPE>
 concept Optional_DerivedFromOptional =
     // This component-private concept models whether a type is derived from one