[Bug c++/33744] New: > within function-style cast incorrectly parsed as closing template angle bracket

[Bug c++/33744] New: > within function-style cast incorrectly parsed as closing template angle bracket

[mdorey at bluearc dot com]

This compiled with 3.3:

template <bool cond>
struct A {
};

A< bool (2 > 1) > x;

It doesn't compile with at least some later versions, including 3.4 and 4.2.1,
with:

x.cpp:4: error: template argument 1 is invalid
x.cpp:4: error: invalid type in declaration before ';' token

Rejects-valid regression in the new parser in 3.4?


-- 
           Summary: > within function-style cast incorrectly parsed as
                    closing template angle bracket
           Product: gcc
           Version: 4.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mdorey at bluearc dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] function-style cast not allowed in template argument

[bangerth at dealii dot org]

------- Comment #1 from bangerth at dealii dot org  2007-10-12 12:52 -------
It's not the parentheses or the greater-than sign, but the cast
that triggers the error. I will have to look up whether a cast
is allowed here. For reference, icc accepts the code.

W.


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|> within function-style cast|function-style cast not
                   |incorrectly parsed as       |allowed in template argument
                   |closing template angle      |
                   |bracket                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] function-style cast not allowed in template argument

[bangerth at dealii dot org]

------- Comment #2 from bangerth at dealii dot org  2007-10-12 13:04 -------
The rule for template non-type arguments of integral type is 14.3.2/1:

1 A  template-argument  for  a non-type, non-template template-parameter
  shall be one of:

  --  an integral constant-expression of integral or  enumeration  type;
  ...

Integral constant-expressions are dealt with in 5.19/1:

  An    integral   constant-expression   can   involve   only   literals
  (_lex.literal_), enumerators, const variables or static  data  members
  of integral or enumeration types initialized with constant expressions
  (_dcl.init_), non-type template parameters of integral or  enumeration
  types,  and  sizeof  expressions.   Floating literals (_lex.fcon_) can
  appear only if they are cast to integral or enumeration  types.   Only
  type  conversions  to  integral  or enumeration types can be used.  In
  particular, except in sizeof expressions,  functions,  class  objects,
  pointers,  or references shall not be used, and assignment, increment,
  decrement, function-call, or comma operators shall not be used.

I do not know whether bool(1) is considered a function-call. Gcc rejects
it as a template argument. However, it does accept (bool)1.

W.


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bangerth at dealii dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] function-style cast not allowed in template argument

[mdorey at bluearc dot com]

------- Comment #3 from mdorey at bluearc dot com  2007-10-12 13:19 -------
(I'm told that) these two function-style casts compile fine on 4.2.1:

template <bool cond>
struct A {
};

A<bool (2)> y;
A<bool (2 < 1)> z;

This is why I suggest the greater-than is a necessary part of the bug.  Do you
have a counter-example, Wolfgang - where the greater-than sign isn't necessary
to cause the same failure?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] [4.1/4.2/4.3 regression] function-style cast and '>' not allowed in template argument

[bangerth at dealii dot org]

------- Comment #4 from bangerth at dealii dot org  2007-10-12 15:21 -------
(In reply to comment #3)
> (I'm told that) these two function-style casts compile fine on 4.2.1:
> 
> template <bool cond>
> struct A {
> };
> 
> A<bool (2)> y;
> A<bool (2 < 1)> z;

Uh, indeed, I see. This is weird indeed. So in other words, these codes
compile:
------------------
  template <bool> struct A {};
  A<bool(1)> a;
  A<bool(1<2)> b;
  A<(bool)(1>2)> c;
------------------
but this one doesn't:
------------------
  template <bool> struct A {};
  A<bool(1>2)> b;
------------------
This is indeed very weird: it only fails with the function-style cast
and the greater-than sign...

Since this worked in gcc 3.3, this is a regression.

W.


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |rejects-valid
      Known to fail|                            |4.1.2 4.2.0 4.3.0
      Known to work|                            |3.3.6
   Last reconfirmed|0000-00-00 00:00:00         |2007-10-12 15:21:49
               date|                            |
            Summary|function-style cast not     |[4.1/4.2/4.3 regression]
                   |allowed in template argument|function-style cast and '>'
                   |                            |not allowed in template
                   |                            |argument
   Target Milestone|---                         |4.2.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] [4.1/4.2/4.3 regression] function-style cast and '>' not allowed in template argument

[mdorey at bluearc dot com]

------- Comment #5 from mdorey at bluearc dot com  2007-10-12 17:11 -------
Adding extra parentheses, such that "bool (2 > 1)" becomes "bool ((2 > 1 ))",
is a work-around.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] [4.1/4.2/4.3 regression] function-style cast and '>' not allowed in template argument

[jakub at gcc dot gnu dot org]

-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jakub at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-10-12 15:21:49         |2007-10-15 12:53:50
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] [4.1/4.2/4.3 regression] function-style cast and '>' not allowed in template argument

[jakub at gcc dot gnu dot org]

------- Comment #6 from jakub at gcc dot gnu dot org  2007-10-26 11:58 -------
Subject: Bug 33744

Author: jakub
Date: Fri Oct 26 11:57:46 2007
New Revision: 129648

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=129648
Log:
        PR c++/33744
        * parser.c (cp_parser_parenthesized_expression_list): Set
        greater_than_is_operator_p to true in between the parens.

        * g++.dg/template/arg6.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/template/arg6.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/parser.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] [4.1/4.2/4.3 regression] function-style cast and '>' not allowed in template argument

[jakub at gcc dot gnu dot org]

------- Comment #7 from jakub at gcc dot gnu dot org  2007-10-26 12:05 -------
Subject: Bug 33744

Author: jakub
Date: Fri Oct 26 12:04:57 2007
New Revision: 129649

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=129649
Log:
        PR c++/33744
        * parser.c (cp_parser_parenthesized_expression_list): Set
        greater_than_is_operator_p to true in between the parens.

        * g++.dg/template/arg6.C: New test.

Added:
    branches/gcc-4_2-branch/gcc/testsuite/g++.dg/template/arg6.C
Modified:
    branches/gcc-4_2-branch/gcc/cp/ChangeLog
    branches/gcc-4_2-branch/gcc/cp/parser.c
    branches/gcc-4_2-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] [4.1/4.2/4.3 regression] function-style cast and '>' not allowed in template argument

[jakub at gcc dot gnu dot org]

------- Comment #8 from jakub at gcc dot gnu dot org  2007-10-26 12:06 -------
Subject: Bug 33744

Author: jakub
Date: Fri Oct 26 12:06:31 2007
New Revision: 129650

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=129650
Log:
        PR c++/33744
        * parser.c (cp_parser_parenthesized_expression_list): Set
        greater_than_is_operator_p to true in between the parens.

        * g++.dg/template/arg6.C: New test.

Added:
    branches/gcc-4_1-branch/gcc/testsuite/g++.dg/template/arg6.C
Modified:
    branches/gcc-4_1-branch/gcc/cp/ChangeLog
    branches/gcc-4_1-branch/gcc/cp/parser.c
    branches/gcc-4_1-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744

[Bug c++/33744] [4.1/4.2/4.3 regression] function-style cast and '>' not allowed in template argument

[jakub at gcc dot gnu dot org]

------- Comment #9 from jakub at gcc dot gnu dot org  2007-10-26 12:07 -------
Fixed.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33744