Move has_formatter into the public fmt namespace. (#1407)

* Move has_formatter into the public fmt namespace.

This will allow users to do SFINAE-friendly checks for
the formattability of a type.

Fixes #1369

2 files changed, 6 insertions, 6 deletions

diff --git a/test/core-test.cc b/test/core-test.cc
index acfd2cd0..c3706002 100644
--- a/test/core-test.cc
+++ b/test/core-test.cc
@@ -453,11 +453,11 @@ template <> struct formatter<enabled_formatter> {
 FMT_END_NAMESPACE
 
 TEST(CoreTest, HasFormatter) {
-  using fmt::internal::has_formatter;
+  using fmt::has_formatter;
   using context = fmt::format_context;
-  EXPECT_TRUE((has_formatter<enabled_formatter, context>::value));
-  EXPECT_FALSE((has_formatter<disabled_formatter, context>::value));
-  EXPECT_FALSE((has_formatter<disabled_formatter_convertible, context>::value));
+  static_assert(has_formatter<enabled_formatter, context>::value, "");
+  static_assert(!has_formatter<disabled_formatter, context>::value, "");
+  static_assert(!has_formatter<disabled_formatter_convertible, context>::value, "");
 }
 
 struct convertible_to_int {
diff --git a/test/format-test.cc b/test/format-test.cc
index 61b893c4..0dce6bad 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1974,8 +1974,8 @@ enum TestEnum { A };
 TEST(FormatTest, Enum) { EXPECT_EQ("0", fmt::format("{}", A)); }
 
 TEST(FormatTest, FormatterNotSpecialized) {
-  EXPECT_FALSE((fmt::internal::has_formatter<fmt::formatter<TestEnum>,
-                                             fmt::format_context>::value));
+  static_assert(!fmt::has_formatter<fmt::formatter<TestEnum>,
+                                    fmt::format_context>::value, "");
 }
 
 #if FMT_HAS_FEATURE(cxx_strong_enums)