From 1ca8bca41414a6e2f235ea69b91378116a8e3afa Mon Sep 17 00:00:00 2001
From: Josh Essman <essman1@llnl.gov>
Date: Wed, 13 Oct 2021 17:43:05 -0500
Subject: [PATCH 1/2] fix: check to make sure both 'if constexpr' and return
 type deduction are available

fix: remaining ifdefs
---
 include/fmt/compile.h | 8 ++++----
 test/compile-test.cc  | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/fmt/compile.h b/include/fmt/compile.h
index 059262f95ef4..1dba3ddb5222 100644
--- a/include/fmt/compile.h
+++ b/include/fmt/compile.h
@@ -156,7 +156,7 @@ struct is_compiled_string : std::is_base_of<compiled_string, S> {};
     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
   \endrst
  */
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 #  define FMT_COMPILE(s) \
     FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
 #else
@@ -179,7 +179,7 @@ const T& first(const T& value, const Tail&...) {
   return value;
 }
 
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 template <typename... Args> struct type_list {};
 
 // Returns a reference to the argument at index N from [first, rest...].
@@ -530,12 +530,12 @@ constexpr auto compile(S format_str) {
     return result;
   }
 }
-#endif  // __cpp_if_constexpr
+#endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
 FMT_MODULE_EXPORT_BEGIN
 
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 
 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,
diff --git a/test/compile-test.cc b/test/compile-test.cc
index 28eef2a24694..1765961b89fa 100644
--- a/test/compile-test.cc
+++ b/test/compile-test.cc
@@ -76,7 +76,7 @@ TEST(compile_test, compile_type_with_get) {
   EXPECT_EQ("42", fmt::format(FMT_COMPILE("{}"), type_with_get()));
 }
 
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 struct test_formattable {};
 
 FMT_BEGIN_NAMESPACE

From 6a7d9004e188b9488d38c34afe2cf72e6dae0a37 Mon Sep 17 00:00:00 2001
From: Josh Essman <essman1@llnl.gov>
Date: Thu, 14 Oct 2021 10:21:40 -0700
Subject: [PATCH 2/2] fix: add workaround for intel parameter pack bug

---
 include/fmt/os.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/fmt/os.h b/include/fmt/os.h
index 297612fc8322..400e2c17b2fe 100644
--- a/include/fmt/os.h
+++ b/include/fmt/os.h
@@ -390,6 +390,13 @@ struct ostream_params {
       : ostream_params(params...) {
     this->buffer_size = bs.value;
   }
+
+// Intel has a bug that results in failure to deduce a constructor
+// for empty parameter packs.
+#if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 2000
+  ostream_params(int new_oflag) : oflag(new_oflag) {}
+  ostream_params(detail::buffer_size bs) : buffer_size(bs.value) {}
+#endif
 };
 
 FMT_END_DETAIL_NAMESPACE