From b029c308f97b6e3418738eb55905f88bdbe7745b Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Mon, 1 Apr 2024 19:44:21 +0200
Subject: [PATCH] Library: sharpen detection of string conversion cases

the metafunction `is_basically<X>` performed only an equality match,
while, given it's current usage, it should also include a subtype-interface-match.

This changes especially the `is_StringLike<S>` metafunction,
both on const references and on classes built on top of string
or string_view.
---
 src/lib/meta/trait.hpp | 9 ++++++++-
 tests/15library.tests  | 8 ++++----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/lib/meta/trait.hpp b/src/lib/meta/trait.hpp
index a4f341e7a..e15d8a2ae 100644
--- a/src/lib/meta/trait.hpp
+++ b/src/lib/meta/trait.hpp
@@ -308,7 +308,7 @@ namespace meta {
   
   /** compare unadorned types, disregarding const and references */
   template<typename T, typename U>
-  struct is_basically
+  struct is_basicallySame
     : is_same <typename Strip<T>::TypeReferred
               ,typename Strip<U>::TypeReferred>
     { };
@@ -323,6 +323,13 @@ namespace meta {
            , is_same<I,S>
            >
     { };
+    
+  /** compare for unadorned base type, disregarding const and references */
+  template<typename S, typename I>
+  struct is_basically
+    : is_Subclass <typename Strip<S>::TypeReferred
+                  ,typename Strip<I>::TypeReferred>
+    { };
   
   /** verify the first (special) type can stand-in for the second */
   template<typename S, typename G>
diff --git a/tests/15library.tests b/tests/15library.tests
index 87b191763..afdeba960 100644
--- a/tests/15library.tests
+++ b/tests/15library.tests
@@ -251,13 +251,13 @@ out-lit: can_lexical2string<StringRRef>	 : Yes
 out-lit: can_convertToString<StringRRef>	 : Yes
 out-lit: use_StringConversion4Stream<StringRRef>	 : No
 out-lit: Type: StrConstRef ......
-out-lit: is_StringLike<StrConstRef>	 : No
-out-lit: BasicallyString<StrConstRef>	 : No
+out-lit: is_StringLike<StrConstRef>	 : Yes
+out-lit: BasicallyString<StrConstRef>	 : Yes
 out-lit: BasicallyCString<StrConstRef>	 : No
 out-lit: std::is_arithmetic<StrConstRef>	 : No
-out-lit: can_lexical2string<StrConstRef>	 : No
+out-lit: can_lexical2string<StrConstRef>	 : Yes
 out-lit: can_convertToString<StrConstRef>	 : Yes
-out-lit: use_StringConversion4Stream<StrConstRef>	 : Yes
+out-lit: use_StringConversion4Stream<StrConstRef>	 : No
 out-lit: Type: CharLit ......
 out-lit: is_StringLike<CharLit>	 : Yes
 out-lit: BasicallyString<CharLit>	 : No