From 965508d9e187d589070c5cd1853cc035b51ea3cf Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Wed, 24 Apr 2024 21:46:32 +0300
Subject: [PATCH] Fix type_name for abstract classes. Fixes #172.

---
 include/boost/core/type_name.hpp |  5 +++--
 test/type_name_test.cpp          | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/boost/core/type_name.hpp b/include/boost/core/type_name.hpp
index 773b5f6..c5cbbbd 100644
--- a/include/boost/core/type_name.hpp
+++ b/include/boost/core/type_name.hpp
@@ -103,7 +103,8 @@ inline std::string fix_typeid_name( char const* n )
 }
 
 // class types can be incomplete
-template<class T> std::string typeid_name_impl( int T::* )
+// but also abstract (T[1] doesn't form)
+template<class T> std::string typeid_name_impl( int T::*, T(*)[1] )
 {
     std::string r = fix_typeid_name( typeid(T[1]).name() );
     return r.substr( 0, r.size() - 4 ); // remove ' [1]' suffix
@@ -116,7 +117,7 @@ template<class T> std::string typeid_name_impl( ... )
 
 template<class T> std::string typeid_name()
 {
-    return typeid_name_impl<T>( 0 );
+    return typeid_name_impl<T>( 0, 0 );
 }
 
 // template names
diff --git a/test/type_name_test.cpp b/test/type_name_test.cpp
index 8ef6677..08cc872 100644
--- a/test/type_name_test.cpp
+++ b/test/type_name_test.cpp
@@ -55,6 +55,13 @@ template<class T1, class T2> struct X
 
 template<class T1, class T2> struct Y;
 
+class W
+{
+public:
+
+    virtual void f() = 0;
+};
+
 enum E1
 {
     e1
@@ -122,6 +129,7 @@ int main()
     TEST(A);
     TEST(B);
     TEST(C);
+    TEST(W);
 
     TEST(E1);
 
@@ -143,6 +151,9 @@ int main()
     TEST(C&);
     TEST(C const&);
 
+    TEST(W const);
+    TEST(W&);
+
 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
 
     TEST(B&&);
@@ -156,6 +167,8 @@ int main()
     TEST(C*);
     TEST(C const* volatile*);
 
+    TEST(W volatile*);
+
     TEST(void*);
     TEST(void const* volatile*);
 
@@ -307,6 +320,8 @@ int main()
 
     TEST(std::pair<C, C>);
 
+    TEST(std::pair<W, W>);
+
     TEST(std::pair<void, void>);
     TEST(std::pair<std::pair<void, void>, void>);
 
@@ -336,9 +351,11 @@ int main()
     TEST(X<A const&, B&> volatile&);
 
     TEST(X<C, C>);
+    TEST(X<W, W>);
 
     TEST(Y<A, B>);
     TEST(Y<C, C>);
+    TEST(Y<W, W>);
 
     TEST(X<std::pair<void, void>, void>);