<format>: Make formatter cast the argument to the correct type be…

…fore constructing `basic_format_arg` (#3723) Co-authored-by: Stephan T. Lavavej <[email protected]>
microsoft · May 31, 2023 · 6a98456 · 6a98456
1 parent a8c4737
commit 6a98456
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Showing 2 changed files with 44 additions and 9 deletions.
diff --git a/stl/inc/format b/stl/inc/format
@@ -695,10 +695,6 @@ public:
         : _Active_state(_Basic_format_arg_type::_Int_type), _Int_state(_Val) {}
     explicit basic_format_arg(const unsigned int _Val) noexcept
         : _Active_state(_Basic_format_arg_type::_UInt_type), _UInt_state(_Val) {}
-    explicit basic_format_arg(const long _Val) noexcept
-        : _Active_state(_Basic_format_arg_type::_Int_type), _Int_state(_Val) {}
-    explicit basic_format_arg(const unsigned long _Val) noexcept
-        : _Active_state(_Basic_format_arg_type::_UInt_type), _UInt_state(_Val) {}
     explicit basic_format_arg(const long long _Val) noexcept
         : _Active_state(_Basic_format_arg_type::_Long_long_type), _Long_long_state(_Val) {}
     explicit basic_format_arg(const unsigned long long _Val) noexcept
@@ -3548,10 +3544,19 @@ struct _Formatter_base {
                 _FormatCtx.arg(static_cast<size_t>(_Specs._Dynamic_precision_index)));
         }
 
-        return _STD visit_format_arg(
-            _Arg_formatter<typename _FormatContext::iterator, _CharT>{
-                ._Ctx = _STD addressof(_FormatCtx), ._Specs = _STD addressof(_Format_specs)},
-            basic_format_arg<_FormatContext>{_Val});
+        using _Erased_type = _Format_arg_traits<_FormatContext>::template _Storage_type<_Ty>;
+
+        _Arg_formatter<typename _FormatContext::iterator, _CharT> _Visitor{
+            ._Ctx = _STD addressof(_FormatCtx), ._Specs = _STD addressof(_Format_specs)};
+#if !_HAS_CXX23
+        if constexpr (is_same_v<_Erased_type, basic_string_view<_CharT>>) {
+            return _STD visit_format_arg(
+                _Visitor, basic_format_arg<_FormatContext>{_Erased_type{_Val.data(), _Val.size()}});
+        } else
+#endif // !_HAS_CXX23
+        {
+            return _STD visit_format_arg(_Visitor, basic_format_arg<_FormatContext>{static_cast<_Erased_type>(_Val)});
+        }
     }
 
 private:

diff --git a/tests/std/tests/P0645R10_text_formatting_custom_formatting/test.cpp b/tests/std/tests/P0645R10_text_formatting_custom_formatting/test.cpp
@@ -96,7 +96,7 @@ struct std::formatter<custom_formattable_type<T>, charT> : std::formatter<T, cha
     }
 };
 
-constexpr void test_disabled_formatter_is_disabled() {
+constexpr void test_disabled_formatter_is_disabled() { // COMPILE-ONLY
     using F = formatter<void, void>;
 
     static_assert(!is_default_constructible_v<F>);
@@ -184,6 +184,21 @@ void test_custom_formattable_type() {
     test_numeric_custom_formattable_type<float, charT>();
     test_numeric_custom_formattable_type<double, charT>();
     test_numeric_custom_formattable_type<long double, charT>();
+
+    test_custom_equiv_with_format<charT, charT>(STR("{}"), charT(' '));
+    test_custom_equiv_with_format<char, charT>(STR("{}"), ' ');
+
+    charT test_str[] = {charT(' '), charT()};
+    test_custom_equiv_with_format<charT*, charT>(STR("{}"), test_str);
+    test_custom_equiv_with_format<const charT*, charT>(STR("{}"), test_str);
+
+    struct traits : char_traits<charT> {};
+    test_custom_equiv_with_format<basic_string<charT, traits>, charT>(STR("{}"), test_str);
+    test_custom_equiv_with_format<basic_string_view<charT, traits>, charT>(STR("{}"), test_str);
+
+    test_custom_equiv_with_format<nullptr_t, charT>(STR("{}"), nullptr);
+    test_custom_equiv_with_format<void*, charT>(STR("{}"), nullptr);
+    test_custom_equiv_with_format<const void*, charT>(STR("{}"), nullptr);
 }
 
 template <class charT>
@@ -201,6 +216,21 @@ void test_mixed_custom_formattable_type() {
     test_numeric_mixed_args_custom_formattable_type<float, charT>();
     test_numeric_mixed_args_custom_formattable_type<double, charT>();
     test_numeric_mixed_args_custom_formattable_type<long double, charT>();
+
+    test_custom_equiv_with_format_mixed<charT, charT>(STR("{}{}"), charT(' '));
+    test_custom_equiv_with_format_mixed<char, charT>(STR("{}{}"), ' ');
+
+    charT test_str[] = {charT(' '), charT()};
+    test_custom_equiv_with_format_mixed<charT*, charT>(STR("{}{}"), test_str);
+    test_custom_equiv_with_format_mixed<const charT*, charT>(STR("{}{}"), test_str);
+
+    struct traits : char_traits<charT> {};
+    test_custom_equiv_with_format_mixed<basic_string<charT, traits>, charT>(STR("{}{}"), test_str);
+    test_custom_equiv_with_format_mixed<basic_string_view<charT, traits>, charT>(STR("{}{}"), test_str);
+
+    test_custom_equiv_with_format_mixed<nullptr_t, charT>(STR("{}{}"), nullptr);
+    test_custom_equiv_with_format_mixed<void*, charT>(STR("{}{}"), nullptr);
+    test_custom_equiv_with_format_mixed<const void*, charT>(STR("{}{}"), nullptr);
 }
 
 int main() {