Re: [PATCH 05/40] command.h: Include scoped_restore_command.h

[Pedro Alves <palves at redhat dot com>]

On 06/27/2017 12:45 PM, Pedro Alves wrote:
> 
> On 06/27/2017 12:30 PM, Yao Qi wrote:
>> Pedro Alves <palves@redhat.com> writes:
>>
>>> This file depends on scoped_restore:
>>>
>>>   extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
>>>
>>> But doesn't include the corresponding header.
>>
>> It is a function declaration, so why does it need scoped_restore?
> 
> I don't understand.  Why wouldn't it?  If the compiler doesn't
> know what scoped_restore_tmpl is, how can that compile?
> 
>>
>> $ make check-headers CHECK_HEADERS="command.h"
>>
>> The command above doesn't complain anything.  I tried gcc-5, 6, and 7.
> 
> Odd.  Let me take another look.

OK, so defs.h includes utils.h, which includes scoped_restore.h,
as found via this hack:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 diff --git c/gdb/command.h w/gdb/command.h
 index aa179e9..f587ebd 100644
 --- c/gdb/command.h
 +++ w/gdb/command.h
 @@ -415,6 +415,8 @@ extern void error_no_arg (const char *) ATTRIBUTE_NORETURN;
 
  extern void dont_repeat (void);
 
 +template <typename T> union scoped_restore_tmpl;
 +
  extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
 
  /* Used to mark commands that don't do anything.  If we just leave the

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

src/gdb/command.h:418:29: error: ‘union’ tag used in naming ‘struct scoped_restore_tmpl<T>’ [-fpermissive]
 template <typename T> union scoped_restore_tmpl;
                             ^
In file included from src/gdb/utils.h:25:0,
                 from src/gdb/defs.h:785,
                 from <command-line>:0:
src/gdb/common/scoped_restore.h:50:7: note: ‘struct scoped_restore_tmpl<T>’ was previously declared here
 class scoped_restore_tmpl : public scoped_restore_base
       ^
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

> I ran into this because at some point I added "#include "command.h"
> somewhere, which then failed to compile.

I don't remember exactly where I added the #include "command.h" that
triggered this.  Must have been somewhere that caused "command.h" to
be included via "defs.h", before the "#include utils.h" line.

Let me try removing it from the series, see if I can still reproduce it.

Thanks,
Pedro Alves