From cce0d2c12b098a9b17c7f9238b6c2897406df52d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Sch=C3=A4pers?= <schaepers@kuennecke.com>
Date: Mon, 1 Aug 2022 16:13:19 +0200
Subject: [PATCH] Supress "zero as null pointer constant" warning

---
 src/core/include/units/bits/algorithm.h      | 3 +++
 src/core/include/units/bits/external/hacks.h | 2 ++
 src/core/include/units/symbol_text.h         | 4 ++++
 3 files changed, 9 insertions(+)

diff --git a/src/core/include/units/bits/algorithm.h b/src/core/include/units/bits/algorithm.h
index 762bb7bc..1ac80362 100644
--- a/src/core/include/units/bits/algorithm.h
+++ b/src/core/include/units/bits/algorithm.h
@@ -80,8 +80,11 @@ constexpr auto lexicographical_compare_three_way(I1 f1, I1 l1, I2 f2, I2 l2, Cmp
 
   bool exhaust1 = (f1 == l1);
   bool exhaust2 = (f2 == l2);
+  UNITS_DIAGNOSTIC_PUSH
+  UNITS_DIAGNOSTIC_IGNORE_ZERO_AS_NULLPOINTER_CONSTANT
   for (; !exhaust1 && !exhaust2; exhaust1 = (++f1 == l1), exhaust2 = (++f2 == l2))
     if (auto c = comp(*f1, *f2); c != 0) return c;
+  UNITS_DIAGNOSTIC_POP
 
   return !exhaust1   ? std::strong_ordering::greater
          : !exhaust2 ? std::strong_ordering::less
diff --git a/src/core/include/units/bits/external/hacks.h b/src/core/include/units/bits/external/hacks.h
index 8d142727..67c1086c 100644
--- a/src/core/include/units/bits/external/hacks.h
+++ b/src/core/include/units/bits/external/hacks.h
@@ -51,6 +51,7 @@
 #define UNITS_DIAGNOSTIC_IGNORE_NON_TEMPLATE_FRIEND UNITS_DIAGNOSTIC_IGNORE("-Wnon-template-friend")
 #define UNITS_DIAGNOSTIC_IGNORE_SHADOW UNITS_DIAGNOSTIC_IGNORE("-Wshadow")
 #define UNITS_DIAGNOSTIC_IGNORE_UNREACHABLE
+#define UNITS_DIAGNOSTIC_IGNORE_ZERO_AS_NULLPOINTER_CONSTANT UNITS_DIAGNOSTIC_IGNORE("-Wzero-as-nullpointer-constant")
 #else
 #define UNITS_DIAGNOSTIC_PUSH UNITS_PRAGMA(warning(push))
 #define UNITS_DIAGNOSTIC_POP UNITS_PRAGMA(warning(pop))
@@ -63,6 +64,7 @@
 #define UNITS_DIAGNOSTIC_IGNORE_NON_TEMPLATE_FRIEND
 #define UNITS_DIAGNOSTIC_IGNORE_SHADOW UNITS_DIAGNOSTIC_IGNORE(4459)
 #define UNITS_DIAGNOSTIC_IGNORE_UNREACHABLE UNITS_DIAGNOSTIC_IGNORE(4702)
+#define UNITS_DIAGNOSTIC_IGNORE_ZERO_AS_NULLPOINTER_CONSTANT
 #endif
 
 #if _LIBCPP_VERSION
diff --git a/src/core/include/units/symbol_text.h b/src/core/include/units/symbol_text.h
index adf138e5..6eb71e6d 100644
--- a/src/core/include/units/symbol_text.h
+++ b/src/core/include/units/symbol_text.h
@@ -24,6 +24,7 @@
 
 // IWYU pragma: begin_exports
 #include <units/bits/external/fixed_string.h>
+#include <units/bits/external/hacks.h>
 #include <compare>
 #include <cstddef>
 #include <cstdint>
@@ -146,7 +147,10 @@ struct basic_symbol_text {
   [[nodiscard]] friend constexpr auto operator<=>(const basic_symbol_text& lhs,
                                                   const basic_symbol_text<StandardCharT2, N2, M2>& rhs) noexcept
   {
+    UNITS_DIAGNOSTIC_PUSH
+    UNITS_DIAGNOSTIC_IGNORE_ZERO_AS_NULLPOINTER_CONSTANT
     if (const auto cmp = lhs.standard() <=> rhs.standard(); cmp != 0) return cmp;
+    UNITS_DIAGNOSTIC_POP
     return lhs.ascii() <=> rhs.ascii();
   }