Hi!
My understanding of the paper is that we just want to promote the CPP_WCHAR
"character constant too long for its type" warning to error as it is already
error for u8, u and U literals.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2022-08-26 Jakub Jelinek <ja...@redhat.com>
PR c++/106647
* charset.cc (wide_str_to_charconst): Implement P2362R3 - Remove
non-encodable wide character literals and multicharacter. For
C++23 use CPP_DL_ERROR instead of CPP_DL_WARNING for
"character constant too long for its type" diagnostics on CPP_WCHAR
literals.
* g++.dg/cpp23/wchar-multi1.C: New test.
* g++.dg/cpp23/wchar-multi2.C: New test.
--- libcpp/charset.cc.jj 2022-08-25 11:54:38.849924475 +0200
+++ libcpp/charset.cc 2022-08-25 18:36:20.650415220 +0200
@@ -2170,7 +2170,11 @@ wide_str_to_charconst (cpp_reader *pfile
character constant is guaranteed to overflow. */
if (str.len > nbwc * 2)
cpp_error (pfile, (CPP_OPTION (pfile, cplusplus)
- && (type == CPP_CHAR16 || type == CPP_CHAR32))
+ && (type == CPP_CHAR16
+ || type == CPP_CHAR32
+ /* In C++23 this is error even for L'ab'. */
+ || (type == CPP_WCHAR
+ && CPP_OPTION (pfile, size_t_literals))))
? CPP_DL_ERROR : CPP_DL_WARNING,
"character constant too long for its type");
--- gcc/testsuite/g++.dg/cpp23/wchar-multi1.C.jj 2022-08-25
18:08:01.973426155 +0200
+++ gcc/testsuite/g++.dg/cpp23/wchar-multi1.C 2022-08-25 18:51:30.476687112
+0200
@@ -0,0 +1,42 @@
+// P2362R3 - Remove non-encodable wide character literals and multicharacter
+// wide character literals.
+// { dg-do compile }
+
+char a = 'a';
+int b = 'ab'; // { dg-warning "multi-character character
constant" }
+int c = '\u05D9'; // { dg-warning "multi-character character
constant" }
+#if __SIZEOF_INT__ > 2
+int d = '\U0001F525'; // { dg-warning "multi-character character
constant" "" { target int32 } }
+#endif
+int e = 'abcd'; // { dg-warning "multi-character
character constant" }
+wchar_t f = L'f';
+wchar_t g = L'gh'; // { dg-error "character constant too long for
its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
+wchar_t h = L'ijkl'; // { dg-error "character constant too long for
its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
+wchar_t i = L'\U0001F525'; // { dg-error "character constant too long for
its type" "" { target { c++23 && { ! 4byte_wchar_t } } } }
+ // { dg-warning "character constant too long
for its type" "" { target { c++20_down && { ! 4byte_wchar_t } } } .-1 }
+#ifdef __cpp_char8_t
+typedef char8_t u8;
+#else
+typedef char u8;
+#endif
+#if __cpp_unicode_characters >= 201411
+u8 j = u8'j';
+u8 k = u8'kl'; // { dg-error "character constant too long for
its type" "" { target c++17 } }
+u8 l = u8'\U0001F525'; // { dg-error "character constant too long for
its type" "" { target c++17 } }
+#endif
+#if __cpp_unicode_characters >= 200704
+char16_t m = u'm';
+char16_t n = u'no'; // { dg-error "character constant too long for
its type" "" { target c++11 } }
+char16_t o = u'\u05D9';
+char16_t p = u'\U0001F525'; // { dg-error "character constant too long for
its type" "" { target c++11 } }
+char32_t q = U'm';
+char32_t r = U'no'; // { dg-error "character constant too long for
its type" "" { target c++11 } }
+char32_t s = U'\u05D9';
+char32_t t = U'\U0001F525';
+#endif
+wchar_t u = L'\u0065\u0301'; // { dg-error "character constant too
long for its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
+wchar_t v = L'é'; // { dg-error "character constant too long for
its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
--- gcc/testsuite/g++.dg/cpp23/wchar-multi2.C.jj 2022-08-25
18:51:53.744386945 +0200
+++ gcc/testsuite/g++.dg/cpp23/wchar-multi2.C 2022-08-25 18:53:03.317489442
+0200
@@ -0,0 +1,43 @@
+// P2362R3 - Remove non-encodable wide character literals and multicharacter
+// wide character literals.
+// { dg-do compile }
+// { dg-options "-fshort-wchar" }
+
+char a = 'a';
+int b = 'ab'; // { dg-warning "multi-character character
constant" }
+int c = '\u05D9'; // { dg-warning "multi-character character
constant" }
+#if __SIZEOF_INT__ > 2
+int d = '\U0001F525'; // { dg-warning "multi-character character
constant" "" { target int32 } }
+#endif
+int e = 'abcd'; // { dg-warning "multi-character
character constant" }
+wchar_t f = L'f';
+wchar_t g = L'gh'; // { dg-error "character constant too long for
its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
+wchar_t h = L'ijkl'; // { dg-error "character constant too long for
its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
+wchar_t i = L'\U0001F525'; // { dg-error "character constant too long for
its type" "" { target { c++23 } } }
+ // { dg-warning "character constant too long
for its type" "" { target { c++20_down } } .-1 }
+#ifdef __cpp_char8_t
+typedef char8_t u8;
+#else
+typedef char u8;
+#endif
+#if __cpp_unicode_characters >= 201411
+u8 j = u8'j';
+u8 k = u8'kl'; // { dg-error "character constant too long for
its type" "" { target c++17 } }
+u8 l = u8'\U0001F525'; // { dg-error "character constant too long for
its type" "" { target c++17 } }
+#endif
+#if __cpp_unicode_characters >= 200704
+char16_t m = u'm';
+char16_t n = u'no'; // { dg-error "character constant too long for
its type" "" { target c++11 } }
+char16_t o = u'\u05D9';
+char16_t p = u'\U0001F525'; // { dg-error "character constant too long for
its type" "" { target c++11 } }
+char32_t q = U'm';
+char32_t r = U'no'; // { dg-error "character constant too long for
its type" "" { target c++11 } }
+char32_t s = U'\u05D9';
+char32_t t = U'\U0001F525';
+#endif
+wchar_t u = L'\u0065\u0301'; // { dg-error "character constant too
long for its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
+wchar_t v = L'é'; // { dg-error "character constant too long for
its type" "" { target c++23 } }
+ // { dg-warning "character constant too long
for its type" "" { target c++20_down } .-1 }
Jakub
