Failing to compile on Linux

[MilosRasic]

Describe the bug

Latest master fails to compile on Linux with the following output:

milosrasic@linux-w1h8:~/Cataclysm-DDA> make -j4 CLANG=1 CCACHE=1 NATIVE=linux64 RELEASE=1 TILES=1 SOUND=1 LOCALIZE=0 CLANG=1 CCACHE=1 USE_HOME_DIR=1
astyle -V: Artistic Style Version 3.1
#define VERSION "0.D-8819-gee41a78b03"
CCACHE_CPP2=1 ccache clang++ -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -DCATA_IN_TOOL -Itools/format -Isrc \
  tools/format/format.cpp src/json.cpp -o tools/format/json_formatter.cgi
no astyle regressions
CCACHE_CPP2=1 ccache clang++  -DRELEASE -DGIT_VERSION -DTILES -DBACKTRACE -DUSE_HOME_DIR -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -c src/action.cpp -o obj/tiles/action.o
CCACHE_CPP2=1 ccache clang++  -DRELEASE -DGIT_VERSION -DTILES -DBACKTRACE -DUSE_HOME_DIR -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -c src/active_item_cache.cpp -o obj/tiles/active_item_cache.o
CCACHE_CPP2=1 ccache clang++  -DRELEASE -DGIT_VERSION -DTILES -DBACKTRACE -DUSE_HOME_DIR -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -c src/activity_handlers.cpp -o obj/tiles/activity_handlers.o
CCACHE_CPP2=1 ccache clang++  -DRELEASE -DGIT_VERSION -DTILES -DBACKTRACE -DUSE_HOME_DIR -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -c src/activity_item_handling.cpp -o obj/tiles/activity_item_handling.o
In file included from src/json.cpp:1:
src/json.h:786:14: error: private field 'reported_unvisited_members' is not used [-Werror,-Wunused-private-field]
        bool reported_unvisited_members = false;
             ^
1 error generated.
make: *** [Makefile:1044: json_formatter] Error 1
make: *** Waiting for unfinished jobs....
^[[A^[[B^Cmake: *** [Makefile:792: obj/tiles/activity_handlers.o] Interrupt
make: *** [Makefile:792: obj/tiles/action.o] Interrupt
make: *** [Makefile:792: obj/tiles/activity_item_handling.o] Interrupt

milosrasic@linux-w1h8:~/Cataclysm-DDA> make -j4 CLANG=1 CCACHE=1 NATIVE=linux64 RELEASE=1 TILES=1 SOUND=1 LOCALIZE=0 CLANG=1 CCACHE=0 USE_HOME_DIR=1
astyle -V: Artistic Style Version 3.1
CCACHE_CPP2=1 ccache clang++ -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -DCATA_IN_TOOL -Itools/format -Isrc \
  tools/format/format.cpp src/json.cpp -o tools/format/json_formatter.cgi
no astyle regressions
CCACHE_CPP2=1 ccache clang++  -DRELEASE -DGIT_VERSION -DTILES -DBACKTRACE -DUSE_HOME_DIR -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -c src/action.cpp -o obj/tiles/action.o
CCACHE_CPP2=1 ccache clang++  -DRELEASE -DGIT_VERSION -DTILES -DBACKTRACE -DUSE_HOME_DIR -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -c src/activity_handlers.cpp -o obj/tiles/activity_handlers.o
CCACHE_CPP2=1 ccache clang++  -DRELEASE -DGIT_VERSION -DTILES -DBACKTRACE -DUSE_HOME_DIR -ffast-math -Os -Werror -Wall -Wextra -Wmissing-declarations -Wold-style-cast -Woverloaded-virtual -Wpedantic -fsigned-char -std=c++14 -MMD -MP -m64 -I/usr/include/SDL2 -D_REENTRANT -DSDL_SOUND -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -I/usr/include/SDL2 -D_REENTRANT -c src/activity_item_handling.cpp -o obj/tiles/activity_item_handling.o
In file included from src/json.cpp:1:
src/json.h:786:14: error: private field 'reported_unvisited_members' is not used [-Werror,-Wunused-private-field]
        bool reported_unvisited_members = false;
             ^
1 error generated.

Was compiling the latest code on this machine for a year now without issues. Also tried without CCACHE and got the same issue.

Tried to comment out reported_unvisited_members in json.h but then compilation failed when it ran into the use of reported_unvisited_members in json.cpp. Looks like astyle or clang might be getting confused by #ifndef CATA_IN_TOOL in json.cpp.

Steps To Reproduce

Steps to reproduce the behavior:

1. Clone the repo or pull from master on a Linux
2. make -j4 CLANG=1 CCACHE=1 NATIVE=linux64 RELEASE=1 TILES=1 SOUND=1 LOCALIZE=0 CLANG=1 CCACHE=1 USE_HOME_DIR=1

Expected behavior

Latest master compiles on Linux.

Versions and configuration

Can't generate this in-game because compilation fails and the old binary I have crashes with the latest master.

• OS: OpenSUSE Tumbleweed
• Game Version: latest master, commit ee41a78
• Graphics version: Tiles
• Mods loaded: N/A

Additional context

clang 8.0.1
ccache 3.7.3
astyle 3.1
cmake 3.15.3

[ZhilkinSerg]

Try running with LINTJSON=0

[molkero]

Had the same issue, disabling clang helped.