Some fixes

Author: H-G-Hristov

libcxx/include/istream

@@ -172,6 +172,7 @@ template <class Stream, class T>
 #    include <__type_traits/conjunction.h>
 #    include <__type_traits/enable_if.h>
 #    include <__type_traits/is_base_of.h>
+#    include <__type_traits/is_same.h>
 #    include <__type_traits/make_unsigned.h>
 #    include <__utility/declval.h>
 #    include <__utility/forward.h>
@@ -292,11 +293,13 @@ public:
   basic_istream& getline(char_type* __s, streamsize __n, char_type __dlm);
 
   basic_istream& ignore(streamsize __n = 1, int_type __dlm = traits_type::eof());
-#    if __LIBCPP_STD_VER >= 26
-  basic_istream& ignore(streamsize __n, char_type __delim)
+#    if _LIBCPP_STD_VER >= 26
+  // _LIBCPP_HIDE_FROM_ABI basic_istream& ignore(streamsize __n, char_type __delim)
+  //   requires is_same_v<char_type, char>;
+  _LIBCPP_HIDE_FROM_ABI basic_istream& ignore(streamsize __n, char_type __delim)
     requires is_same_v<char_type, char>
   {
-    return ignore(__n, traits::to_int_type(__delim));
+    return this->ignore(__n, _Traits::to_int_type(__delim));
   }
 #    endif
   int_type peek();
@@ -873,6 +876,14 @@ basic_istream<_CharT, _Traits>& basic_istream<_CharT, _Traits>::ignore(streamsiz
   return *this;
 }
 
+// #    if _LIBCPP_STD_VER >= 26
+// template <class _CharT, class _Traits>
+// basic_istream& basic_istream<_CharT, _Traits>&
+// basic_istream<_CharT, _Traits>::ignore(streamsize __n, char_type __delim) {
+//   return this->ignore(__n, _Traits::to_int_type(__delim));
+// }
+// #    endif
+
 template <class _CharT, class _Traits>
 typename basic_istream<_CharT, _Traits>::int_type basic_istream<_CharT, _Traits>::peek() {
   ios_base::iostate __state = ios_base::goodbit;

libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore.char_type.pass.cpp

@@ -25,17 +25,14 @@
 int main(int, char**) {
   std::istringstream in("\xF0\x9F\xA4\xA1 Clown Face");
   in.ignore(100, '\xA1'); // ignore up to '\xA1' delimiter,
-                                   // previously might have ignored to EOF
+                          // previously might have ignored to EOF
 
-  assert(in.gcount() == 4);        // 4 bytes were ignored
-  assert(in.peek() == ' ');        // next character is a space
+  assert(in.gcount() == 4); // 4 bytes were ignored
+  assert(in.peek() == ' '); // next character is a space
 
-  std::string s1;                  // read the next word
-  in >> s1;
-  assert(s1 == "Clown");
-
-  in.ignore(100, -1L);    // ambiguous overload,
-                                   // previously equivalent to (int)-1L
+  std::string str; // read the next word
+  in >> str;
+  assert(str == "Clown");
 
   return 0;
 }

libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/ignore.verify.cpp

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: std-at-least-c++26
+
+// Requires 396145d in the built library.
+// XFAIL: using-built-library-before-llvm-9
+
+// <istream>
+
+// basic_istream& ignore(streamsize n, char_type delim);
+
+#include <cassert>
+#include <sstream>
+#include <string>
+
+#include "test_macros.h"
+
+void test() {
+  std::istringstream in("\xF0\x9F\xA4\xA1 Clown Face");
+  in.ignore(100, -1L); // expected-error {{call to member function 'ignore' is ambiguous}}
+}