[package - head-amd64-default][games/simutrans] Failed for simutrans-120.2.2 in build

[Dimitry Andric]

On 29 Jul 2017, at 01:59, Tijl Coosemans <tijl at freebsd.org> wrote:
> 
> On Fri, 28 Jul 2017 19:54:04 +0200 Dimitry Andric <dim at FreeBSD.org> wrote:
>> On 28 Jul 2017, at 13:55, Tijl Coosemans <tijl at freebsd.org> wrote:
>>> 
>>> On Thu, 27 Jul 2017 21:42:01 +0000 pkg-fallout at FreeBSD.org wrote:
>> ...
>>>> In file included from squirrel/squirrel/sqvm.cc:5:
>>>> In file included from /usr/include/c++/v1/math.h:310:
>>>> /usr/include/c++/v1/limits:149:85: error: expected expression
>>>>   _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return type();}
>>>>                                                                                   ^
>>>> squirrel/squirrel/sqobject.h:131:24: note: expanded from macro 'type'
>>>> #define type(obj) ((obj)._type)
>>>>                      ^
>>> 
>>> Simutrans code defines 'type' as a macro.  Shouldn't libc++ headers use
>>> _type or __type or something?
>> 
>> No, the member name 'type' is used in many classes in the C++ standard
>> library, for example all the traits in <type_traits>.  Programs should
>> not attempt to redefine this, at least not as a macro.
>> 
>> Note that this also doesn't work with libstdc++, e.g.:
>> 
>> $ cat boom.cpp
>> #define type "nope, this will not work"
>> #include <type_traits>
>> 
>> and then:
>> 
>> $ g++ -c boom.cpp
>> boom.cpp:1:14: error: expected unqualified-id before string constant
>> #define type "nope, this will not work"
>>              ^
>> boom.cpp:1:14: error: expected class-name before string constant
>> #define type "nope, this will not work"
>>              ^
>> boom.cpp:1:14: error: expected '{' before string constant
>> boom.cpp:1:14: error: expected class-name before string constant
>> #define type "nope, this will not work"
>>              ^
>> boom.cpp:1:14: error: expected '{' before string constant
>> boom.cpp:1:14: error: expected class-name before string constant
>> #define type "nope, this will not work"
>>              ^
>> boom.cpp:1:14: error: expected '{' before string constant
>> boom.cpp:1:14: error: expected class-name before string constant
>> #define type "nope, this will not work"
>>              ^
>> boom.cpp:1:14: error: expected '{' before string constant
>> boom.cpp:1:14: error: expected unqualified-id before string constant
>> #define type "nope, this will not work"
>>              ^
>> In file included from boom.cpp:3:0:
>> /usr/local/lib/gcc6/include/c++/type_traits:212:60: error: template argument 1 is invalid
>>     : public __is_void_helper<typename remove_cv<_Tp>::type>::type
>>                                                            ^
>> /usr/local/lib/gcc6/include/c++/type_traits:212:61: error: expected '{' before '::' token
>>     : public __is_void_helper<typename remove_cv<_Tp>::type>::type
>>                                                             ^~
>> [...and lots more errors like this...]
> 
> The code does not include <type_traits> or any of that C++11 stuff.  It
> includes <math.h>.  This works with libstdc++ because it doesn't have
> <math.h>, but it would also work when <cmath> was included, because
> libstdc++ uses __type everywhere (and __enable_if and __is_arithmetic,
> etc. where libc++ headers use enable_if and is_arithmetic).  The
> libstdc++ way makes more sense.  You cannot expect C++98 code to know
> about reserved identifiers in C++11 or C++11 code to know about reserved
> identifiers in later standards.

The usage of "type" as a name has been in libc++ since it was first
imported upstream about 7 years ago, and the failure you showed is the
first instance of such a name clash I have ever heard of.  Therefore, I
don't think it is too much trouble to change one older program to use a
slightly different define.

-Dimitry

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