Work around GCC co_await bugs in test macros

Related GCC issues:
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101027
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116775

Related Catch2 issues:
* #2591
* #2925

Author: vasama

src/catch2/internal/catch_compiler_capabilities.hpp

@@ -130,26 +130,6 @@
 
 #endif // __clang__
 
-// As of this writing, IBM XL's implementation of __builtin_constant_p has a bug
-// which results in calls to destructors being emitted for each temporary,
-// without a matching initialization. In practice, this can result in something
-// like `std::string::~string` being called on an uninitialized value.
-//
-// For example, this code will likely segfault under IBM XL:
-// ```
-// REQUIRE(std::string("12") + "34" == "1234")
-// ```
-//
-// Similarly, NVHPC's implementation of `__builtin_constant_p` has a bug which
-// results in calls to the immediately evaluated lambda expressions to be
-// reported as unevaluated lambdas.
-// https://developer.nvidia.com/nvidia_bug/3321845.
-//
-// Therefore, `CATCH_INTERNAL_IGNORE_BUT_WARN` is not implemented.
-#if defined( __ibmxl__ ) || defined( __CUDACC__ ) || defined( __NVCOMPILER )
-#    define CATCH_INTERNAL_CONFIG_NO_USE_BUILTIN_CONSTANT_P
-#endif
-
 
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -390,15 +370,6 @@
 #define CATCH_CONFIG_USE_BUILTIN_CONSTANT_P
 #endif
 
-#if defined( CATCH_CONFIG_USE_BUILTIN_CONSTANT_P ) && \
-    !defined( CATCH_CONFIG_NO_USE_BUILTIN_CONSTANT_P )
-#    define CATCH_INTERNAL_IGNORE_BUT_WARN( ... )                                              \
-        (void)__builtin_constant_p( __VA_ARGS__ ) /* NOLINT(cppcoreguidelines-pro-type-vararg, \
-                                                     hicpp-vararg) */
-#else
-#    define CATCH_INTERNAL_IGNORE_BUT_WARN( ... )
-#endif
-
 // Even if we do not think the compiler has that warning, we still have
 // to provide a macro that can be used by the code.
 #if !defined(CATCH_INTERNAL_START_WARNINGS_SUPPRESSION)

src/catch2/internal/catch_run_context.cpp

@@ -328,6 +328,8 @@ namespace Catch {
 
         bool lastAssertionPassed() { return Detail::g_lastAssertionPassed; }
 
+        volatile bool volatileFalse = false;
+
     } // namespace Detail
 
     RunContext::RunContext(IConfig const* _config, IEventListenerPtr&& reporter)

src/catch2/internal/catch_test_macro_impl.hpp

@@ -18,6 +18,10 @@ namespace Catch {
     namespace Detail {
         // Defined in catch_run_context.cpp, where the thread-local data lives.
         bool lastAssertionPassed();
+
+        // A technically non-constant false. Prevents the compiler from warning
+        // about or eliminating constant branch conditions.
+        extern volatile bool volatileFalse;
     }
 }
 
@@ -48,7 +52,8 @@ namespace Catch {
 #define INTERNAL_CATCH_TEST( macroName, resultDisposition, ... ) \
     do { /* NOLINT(bugprone-infinite-loop) */ \
         /* The expression should not be evaluated, but warnings should hopefully be checked */ \
-        CATCH_INTERNAL_IGNORE_BUT_WARN(__VA_ARGS__); \
+        if(::Catch::Detail::volatileFalse) \
+            (void)(__VA_ARGS__); \
         Catch::AssertionHandler catchAssertionHandler( macroName##_catch_sr, CATCH_INTERNAL_LINEINFO, CATCH_INTERNAL_STRINGIFY(__VA_ARGS__), resultDisposition ); \
         INTERNAL_CATCH_TRY { \
             CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
@@ -57,8 +62,7 @@ namespace Catch {
             CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION \
         } INTERNAL_CATCH_CATCH( catchAssertionHandler ) \
         catchAssertionHandler.complete(); \
-    } while( (void)0, (false) && static_cast<const bool&>( !!(__VA_ARGS__) ) ) // the expression here is never evaluated at runtime but it forces the compiler to give it a look
-    // The double negation silences MSVC's C4800 warning, the static_cast forces short-circuit evaluation if the type has overloaded &&.
+    } while(false)
 
 ///////////////////////////////////////////////////////////////////////////////
 #define INTERNAL_CATCH_IF( macroName, resultDisposition, ... ) \