From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 17 Nov 2020 15:26:29 +0000 (+0000)
Subject: libstdc++: Fix unconditional definition of __cpp_lib_span in <version> [PR 97869}
X-Git-Tag: releases/gcc-10.3.0~620
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=992643655c872f8332f9e8e453631a8fad52943a;p=thirdparty%2Fgcc.git

libstdc++: Fix unconditional definition of __cpp_lib_span in <version> [PR 97869}

The <span> header is empty unless Concepts are supported, but <version>
defines the __cpp_lib_span feature test macro unconditionally. It should
be guarded by the same conditions as in <span>.

libstdc++-v3/ChangeLog:

	PR libstdc++/97869
	* include/precompiled/stdc++.h: Include <coroutine>.
	* include/std/version (__cpp_lib_span): Check __cpp_lib_concepts
	before defining.

(cherry picked from commit ecf65330c11544ebf35e198087b4a42be089c620)
---

diff --git a/libstdc++-v3/include/precompiled/stdc++.h b/libstdc++-v3/include/precompiled/stdc++.h
index 7518a98c25a0..5b8f6340448f 100644
--- a/libstdc++-v3/include/precompiled/stdc++.h
+++ b/libstdc++-v3/include/precompiled/stdc++.h
@@ -137,6 +137,9 @@
 #include <bit>
 #include <compare>
 #include <concepts>
+#if __cpp_impl_coroutine
+# include <coroutine>
+#endif
 #include <numbers>
 #include <ranges>
 #include <span>
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index c3a5bd26e636..e899a1e6d990 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -218,7 +218,9 @@
 # define __cpp_lib_ranges 201911L
 #endif
 #define __cpp_lib_shift 201806L
-#define __cpp_lib_span 202002L
+#if __cpp_lib_concepts
+# define __cpp_lib_span 202002L
+#endif
 #define __cpp_lib_ssize 201902L
 #define __cpp_lib_starts_ends_with 201711L
 #define __cpp_lib_to_address 201711L