Update clang reporting

include/lucenaBAL/details/compilers/lbalAppleClangInitialization.hpp

@@ -194,7 +194,8 @@
 	//	ever deal with Apple LLVM versions with support for SD-6 macros.
 
 	//	As of vanilla clang 8, this is disabled by default in order to avoid
-	//	ABI-breaking changes. It’s unclear when it will be enabled by default.
+	//	ABI-breaking changes. It’s unclear when it will be enabled by default (it
+  //  has not been re-enabled by default as of clang 18).
 	//
 	//	__SEEME__ This explicit test is here for documentation, but could
 	//	actually be dropped as the common test will serve just as well.
@@ -219,9 +220,11 @@
 	//	- __cpp_nontype_template_parameter_auto is undefined; testing
 	//		suggests the feature is implemented; no tracking
 
-	//	As of vanilla clang 8, this is disabled by default in order to avoid a
-	//	defect introduced by the associated proposal (which was intended to
-	//	resolve another defect).
+	//	As of vanilla clang 8, this is disabled by default in order to avoid
+  //  breaking code which was previously legal but is now malformed (thereby
+  //  perpetuating the defect for over a decade in order to support a few
+  //  months worth of bad code). To enable the DR fix, it is necessary to pass
+  //  in `-frelaxed-template-template-args` to the compiler.
 	//
 	//	__SEEME__ This explicit test is here for documentation, but could
 	//	actually be dropped as the common test will serve just as well.

include/lucenaBAL/details/compilers/lbalAppleClangPostInitialization.hpp

@@ -29,7 +29,7 @@
 	equivalent SD-6 tokens are undefined; this can happen because the
 	implementation does not supply them, or because the feature in question is
 	unavailable. We resolve this here, if needed. Note that any situation that
-	would require us to pre-emptively disablea feature would have been handled
+	would require us to pre-emptively disable a feature would have been handled
 	previously in `lbalAppleClangInitialization.hpp`.
 */
 
@@ -86,6 +86,14 @@
 			#define LBAL_CPP20_INIT_STATEMENTS_FOR_RANGE_BASED_FOR 1L
 		#endif
 	#endif
+
+	#if (__clang_major__ >= 12) && (LBAL_cpp_version > LBAL_CPP17_VERSION)
+		//	__SEEME__ There is no SD-6 token for this. Apple clang started
+    //  supporting it initially in a bug fix in the Xcode 10-series.
+		#if !defined(LBAL_CPP20_DEFAULT_CONSTRUCTIBLE_AND_ASSIGNABLE_STATELESS_LAMBDAS)
+      #define LBAL_CPP20_DEFAULT_CONSTRUCTIBLE_AND_ASSIGNABLE_STATELESS_LAMBDAS 1L
+		#endif
+	#endif
 #else
 	#error "lbalAppleClangPostInitialization.hpp was directly included while using the wrong compiler"
 #endif

include/lucenaBAL/details/compilers/lbalClangInitialization.hpp

@@ -164,8 +164,9 @@
 	//	C++14 features
 
 	//	As of vanilla clang 8, this is disabled by default in order to avoid
-	//	ABI-breaking changes. It’s unclear when it will be enabled by default.
-	//
+	//	ABI-breaking changes. It’s unclear when it will be enabled by default (it
+  //  has not been re-enabled by default as of clang 18).
+  //
 	//	__SEEME__ This explicit test is here for documentation, but could
 	//	actually be dropped as the common test will serve just as well.
 	#if (__cpp_sized_deallocation >= 201309L)
@@ -177,9 +178,11 @@
 
 	//	C++17 features
 
-	//	As of vanilla clang 8, this is disabled by default in order to avoid a
-	//	defect introduced by the associated proposal (which was intended to
-	//	resolve another defect).
+	//	As of vanilla clang 8, this is disabled by default in order to avoid
+  //  breaking code which was previously legal but is now malformed (thereby
+  //  perpetuating the defect for over a decade in order to support a few
+  //  months worth of bad code). To enable the DR fix, it is necessary to pass
+  //  in `-frelaxed-template-template-args` to the compiler.
 	//
 	//	__SEEME__ This explicit test is here for documentation, but could
 	//	actually be dropped as the common test will serve just as well.

include/lucenaBAL/details/compilers/lbalClangPostInitialization.hpp

@@ -71,7 +71,8 @@
 		//	version check and a language test. This will miss back-ported
 		//	extensions, but will pick up preview implementations.
 
-		#if !defined(LBAL_CPP20_DEFAULT_CONSTRUCTIBLE_AND_ASSIGNABLE_STATELESS_LAMBDAS)
+    //	__SEEME__ There is no SD-6 token for this.
+    #if !defined(LBAL_CPP20_DEFAULT_CONSTRUCTIBLE_AND_ASSIGNABLE_STATELESS_LAMBDAS)
 			#define LBAL_CPP20_DEFAULT_CONSTRUCTIBLE_AND_ASSIGNABLE_STATELESS_LAMBDAS 1L
 		#endif
 

include/lucenaBAL/lbalFeatureSetup.hpp

@@ -2671,6 +2671,11 @@
 	latest supported variant, or `0` if this variant is not supported.
 	- [201411L](https://wg21.link/n4268)
 	- [201911L](https://wg21.link/P1907R1)
+
+ @remarks Most mainstream compilers support this, except for `float`-type
+ arguments, but there is no “partial support” value to qualify this. The latest
+ versions of some compilers even support `floats` “experimentally”, but have
+ not yet updated the macro value.
 */
 #ifndef LBAL_CPP20_NONTYPE_TEMPLATE_ARGS_FIXES
 	#define LBAL_CPP20_NONTYPE_TEMPLATE_ARGS_FIXES 0