Test and fix compiled format_to_n and formatted_size

include/fmt/compile.h

@@ -553,16 +553,15 @@ format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
                                          const CompiledFormat& cf,
                                          const Args&... args) {
   auto it =
-      cf.format_to(internal::truncating_iterator<OutputIt>(out, n), args...);
+      format_to(internal::truncating_iterator<OutputIt>(out, n), cf, args...);
   return {it.base(), it.count()};
 }
 
 template <typename CompiledFormat, typename... Args>
 std::size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
-  return cf
-      .format_to(
-          internal::counting_iterator<typename CompiledFormat::char_type>(),
-          args...)
+  return fmt::format_to(
+             internal::counting_iterator<typename CompiledFormat::char_type>(),
+             cf, args...)
       .count();
 }
 

test/compile-test.cc

@@ -505,13 +505,16 @@ TEST(CompileTest, FormatToIterator) {
   EXPECT_EQ(L"42", ws);
 }
 
-TEST(CompileTest, FormatToBackInserter) {
-  std::string s;
-  const auto prepared = fmt::compile<int>("4{}");
-  fmt::format_to(std::back_inserter(s), prepared, 2);
-  EXPECT_EQ("42", s);
-  std::wstring ws;
-  const auto wprepared = fmt::compile<int>(L"4{}");
-  fmt::format_to(std::back_inserter(ws), wprepared, 2);
-  EXPECT_EQ(L"42", ws);
+TEST(CompileTest, FormatToN) {
+  char buf[5];
+  auto f = fmt::compile<int>("{:10}");
+  auto result = fmt::format_to_n(buf, 5, f, 42);
+  EXPECT_EQ(result.size, 10);
+  EXPECT_EQ(result.out, buf + 5);
+  EXPECT_EQ(fmt::string_view(buf, 5), "     ");
+}
+
+TEST(CompileTest, FormattedSize) {
+  auto f = fmt::compile<int>("{:10}");
+  EXPECT_EQ(fmt::formatted_size(f, 42), 10);
 }