[Bug c++/50941] New: [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[Bug c++/50941] New: [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

             Bug #: 50941
           Summary: [C++0x] user-defined string literals provide incorrect
                    length for wchar_t, char16_t, and char32_t
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: daniel.kruegler@googlemail.com
                CC: jason@redhat.com


gcc 4.7.0 20111029 (experimental) in C++0x mode rejects the following code:

//---
typedef decltype(sizeof(0)) size_type;

constexpr size_type operator "" _len(const char*, size_type len)
{
  return len;
}

constexpr size_type operator "" _len(const wchar_t*, size_type len)
{
  return len;
}

constexpr size_type operator "" _len(const char16_t*, size_type len)
{
  return len;
}

constexpr size_type operator "" _len(const char32_t*, size_type len)
{
  return len;
}

static_assert(  ""_len == 0, "Ouch"); // OK
static_assert(u8""_len == 0, "Ouch"); // OK
static_assert( L""_len == 0, "Ouch"); // Error
static_assert( u""_len == 0, "Ouch"); // Error
static_assert( U""_len == 0, "Ouch"); // Error
//---

With 

"error: static assertion failed: "Ouch"" 

at the marked lines.

The code should be accepted.

It turns out that for wchar_t, char16_t, and char32_t string literals the
provided length is 1, not 0. But according to N3290 2.14.8 p5 and 2.14.5 p15
the provided length value should also be 0 in above examples. This problem also
occurs for non-empty strings: The length value is always too large by 1 for the
mentioned string types.

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> 2011-11-01 10:24:59 UTC ---
I need to make a correction in regard to the actually provided length values:

a) The following assertions incorrectly hold:

static_assert( L""_len == 1, "Ouch");
static_assert( u""_len == 1, "Ouch");
static_assert( U""_len == 3, "Ouch");

b) For non-empty strings other "value patterns" occur, e.g. these tests

static_assert(L"1"_len == 3, "Ouch");
static_assert(u"1"_len == 3, "Ouch");
static_assert(U"1"_len == 7, "Ouch");

evaluate to true, even though the length should be 1 in all these cases.

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[3dw4rd at verizon dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

--- Comment #2 from Ed Smith-Rowland <3dw4rd at verizon dot net> 2011-11-01 21:52:13 UTC ---
Divide by sizeof, then subtract 1.
Working on a patch.

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[3dw4rd at verizon dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

--- Comment #3 from Ed Smith-Rowland <3dw4rd at verizon dot net> 2011-11-02 04:22:20 UTC ---
Created attachment 25685
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25685
Patch with testcase.

Patch.  Testcase modified from initial report.
Thank you Daniel for the report.

Jason, should I rename the testcase after the bug number?

Ed

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-11-02 07:43:06 UTC ---
Please watch your formatting:
UNIT ( TREE_TYPE( TREE_TYPE(value))))
should have been:
UNIT (TREE_TYPE (TREE_TYPE (value))))

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[3dw4rd at verizon dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

Ed Smith-Rowland <3dw4rd at verizon dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #25685|0                           |1
        is obsolete|                            |

--- Comment #5 from Ed Smith-Rowland <3dw4rd at verizon dot net> 2011-11-03 01:14:44 UTC ---
Created attachment 25697
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25697
New patch with minor formatting and PR note in the testcase.

New patch.
Minor formatting.
Mention the PR in the testcase.

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[3dw4rd at verizon dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

--- Comment #6 from Ed Smith-Rowland <3dw4rd at verizon dot net> 2011-11-03 01:16:02 UTC ---
Ummm....

So do I post a patch and CL to gcc-patches if this is OK?

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-04 16:16:18 UTC ---
Author: jason
Date: Fri Nov  4 16:16:09 2011
New Revision: 180961

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180961
Log:
    PR c++/50941
    * parser.c (cp_parser_userdef_string_literal): Fix string length.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/udlit-string-length.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/parser.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/50941] [C++0x] user-defined string literals provide incorrect length for wchar_t, char16_t, and char32_t

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50941

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #8 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-04 16:25:13 UTC ---
Fixed.