std=c++17 treated as pre-C++11 for diagnostics

[dzhu]

Please mark appropriate

• [x] rtags (rdm/rc/rp)
• Emacs Lisp
  • [ ] ac-rtags.el
  • [ ] company-rtags.el
  • [ ] helm-rtags.el
  • [ ] flycheck-rtags.el
  • [ ] ivy-rtags.el
  • [x] rtags.el

Problem description

When a file has -std=c++17 in its compilation arguments, diagnostics appear in the file as if it is being treated as pre-C++11.

Expected behavior/reproduction steps

• Write file a.cc in emacs, containing using x = int;.
• Run echo 'g++ -std=c++17 a.cc' | rc -c.
• No diagnostics should appear in the buffer.

Actual behavior

• Diagnostic appears on int, with the minibuffer showing Parse Issue: alias declarations are a C++11 extension: -Wc++11-extensions.
• Rerunnng echo | rc with c++11 or c++14 immediately causes the diagnostic to disappear, and rerunning with c++17causes it to reappear.
• rtags-compilation-flags and rtags-compile-file know about the correct version in all cases.

Environment

• Ubuntu 16.04, emacs 24.5.1 (minimal config, loading only rtags-20180224.1658 from MELPA), rtags git-6f084a31
• LLVM/Clang version: 5.0

[stellarstriker]

+1

OS: Fedora 26 rtags: tag v2.18 Clang: 4.0.1

[Andersbakken]

This seems to just work for me. I am running clang 6.0 however. Is it possible that your libclang doesn't support c++17?

Can you try to compile the example with the clang executable that goes with the libclang rtags is using?

[dzhu]

Oops, rtags was compiled with libclang 3.8. Recompiling with 5.0 fixes it. Thanks!

[Andersbakken]

Glad to hear.

Anders

On Tue, Mar 27, 2018 at 4:35 AM, dzhu notifications@github.com wrote:

Closed #1167 https://github.com/Andersbakken/rtags/issues/1167.

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