commit 084635aa80daa45403aebd86712b2c61779c4173
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Jun 28 15:16:08 2021

    libstdc++: Remove redundant explicit instantiations
    
    These function templates are explicitly specialized for char and wchar_t
    streambufs, so the explicit instantiations do nothing. Remove them, to
    avoid confusion.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/streambuf.tcc (__copy_streambufs_eof): Remove
            explicit instantiation declarations.
            * src/c++11/streambuf-inst.cc (__copy_streambufs_eof): Remove
            explicit instantiation definitions.

diff --git a/libstdc++-v3/include/bits/streambuf.tcc b/libstdc++-v3/include/bits/streambuf.tcc
index cbcfb0c790e..22464c4401c 100644
--- a/libstdc++-v3/include/bits/streambuf.tcc
+++ b/libstdc++-v3/include/bits/streambuf.tcc
@@ -147,25 +147,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // which are defined via explicit instantiations elsewhere.
 #if _GLIBCXX_EXTERN_TEMPLATE
   extern template class basic_streambuf<char>;
+
   extern template
     streamsize
     __copy_streambufs(basic_streambuf<char>*,
 		      basic_streambuf<char>*);
-  extern template
-    streamsize
-    __copy_streambufs_eof(basic_streambuf<char>*,
-			  basic_streambuf<char>*, bool&);
 
 #ifdef _GLIBCXX_USE_WCHAR_T
   extern template class basic_streambuf<wchar_t>;
+
   extern template
     streamsize
     __copy_streambufs(basic_streambuf<wchar_t>*,
 		      basic_streambuf<wchar_t>*);
-  extern template
-    streamsize
-    __copy_streambufs_eof(basic_streambuf<wchar_t>*,
-			  basic_streambuf<wchar_t>*, bool&);
 #endif
 #endif
 
diff --git a/libstdc++-v3/src/c++11/streambuf-inst.cc b/libstdc++-v3/src/c++11/streambuf-inst.cc
index 497f54e193f..c2c2ee9a688 100644
--- a/libstdc++-v3/src/c++11/streambuf-inst.cc
+++ b/libstdc++-v3/src/c++11/streambuf-inst.cc
@@ -40,11 +40,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     streamsize
     __copy_streambufs(basic_streambuf<char>*, basic_streambuf<char>*);
 
-  template
-    streamsize
-    __copy_streambufs_eof(basic_streambuf<char>*,
-			  basic_streambuf<char>*, bool&);
-
 #ifdef _GLIBCXX_USE_WCHAR_T
   // wstreambuf
   template class basic_streambuf<wchar_t>;
@@ -52,11 +47,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template
     streamsize
     __copy_streambufs(basic_streambuf<wchar_t>*, basic_streambuf<wchar_t>*);
-
-  template
-    streamsize
-    __copy_streambufs_eof(basic_streambuf<wchar_t>*,
-			  basic_streambuf<wchar_t>*, bool&);
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION