Re: [boost] [run-clang-tidy] new replacement overlaps with an existing replacement

Subject: Re: [boost] [run-clang-tidy] new replacement overlaps with an existing replacement
From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2018-12-11 23:15:24

FYI, the issue was due to not so optimal translation units configuration.
Instead of bundle of TU-s with self-contained headers tests (one GIL's
header per .cpp)
I fixed generated single .cpp with all headers included
(https://github.com/boostorg/gil/pull/184).
Then, I run clang-tidy against that single .cpp file.
This does the trick and the modernize-use-using fixes are applied correctly.
More details here
http://lists.llvm.org/pipermail/cfe-users/2018-December/001454.html

Best regards,
Mateusz
On Mon, 10 Dec 2018 at 22:18, Mateusz Loskot <mateusz_at_[hidden]> wrote:
>
> (I'm forwarding here my clang-tidy problem I posted to cfe-user mailing list,
> since it touches Boost library, a highly templated library, and I'm hoping
> we have experienced clang-tidy users among Boost developers.
> Considering it a part of Boost library development, I hope it is not
> off-topic here.)
>
> ---------- Forwarded message ---------
> From: Mateusz Loskot <mateusz_at_[hidden]>
> Date: Mon, 10 Dec 2018 at 22:14
> Subject: [run-clang-tidy] new replacement overlaps with an existing replacement
> To: <cfe-users_at_[hidden]>
>
> Hi,
>
> I'm running clang-tidy 7.0 (also tried 5.0) to modernise some aspects
> of Boost.GIL (https://github.com/boostorg/gil) source code.
>
> I've noticed, clang-tidy 7.0 (also 5.0) does not apply fixes for some of
> modernize-use-* checks, especially modernize-use-using.
>
> I run it this way:
>
> ```
> cd ${BOOST_ROOT}/libs/gil
> cmake -S . -B _build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON ..
> run-clang-tidy.py -p=_build -header-filter='boost\/gil\/.*'
> -checks='-*,modernize-use-using' -fix
> ```
>
> Then, I see huge number of "The new replacement overlaps with an
> existing replacement." diagnostics.
> Below, I copied an extract that hopefully is useful to figure out what
> is happening and going wrong.
>
> Basically, there are two class templates and a bunch of tag types:
>
> 1. file_stream_device
> https://github.com/boostorg/gil/blob/e0288ece9ec50534e7d02166863d6799a5932e25/include/boost/gil/io/device.hpp#L49
> 2. get_write_device with partial specialisations, `enable_if`-ed
> https://github.com/boostorg/gil/blob/e0288ece9ec50534e7d02166863d6799a5932e25/include/boost/gil/io/get_write_device.hpp#L19-L59
>
> The file_stream_device is specialised for a tag and final
> get_write_device specialisation is matched.
>
> And, clang-tidy tries to substitute this alias in get_write_device
>
> typedef detail::file_stream_device< FormatTag > type;
>
> not with
>
> using type = detail::file_stream_device< FormatTag > ;
>
> but with `using type` for each FormatTag-based specialisation
>
> ```
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<bmp_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<bmp_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<jpeg_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<png_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<png_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<png_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<pnm_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<targa_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<targa_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<tiff_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> New replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<tiff_tag>"
> Existing replacement:
> /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp:
> 1885:+52:"using type = detail::file_stream_device<FormatTag>"
> The new replacement overlaps with an existing replacement.
> ```
>
> Why clang-tidy tries to re-fix the typedef with new replacement
> instead of keeping the existing one, the generic one?
>
> i.e. using type = detail::file_stream_device<FormatTag>
>
> I've tried to prepare a minimal example, but I couldn't reproduce this issue.
>
> I observed, that if I manually prepare compile_database.json with
> single .cpp file that just `#include <boost/gil/io/device.hpp>`,
> that is the header with definition of the base templates
> and no definitions with higher level specialisations for format tags
> are included,
> then clang-tidy applies the expected fixes without any warnings.
>
> Could anyone share any insights about this issue?
>
> Best regards,
> --
> Mateusz Loskot, http://mateusz.loskot.net

-- 
Mateusz Loskot, http://mateusz.loskot.net