Unable to compile ada-mode

[Colton Lewis]

Package: emacs, ada-mode

I have recently tried and failed to compile ada-mode.
This may be a bug in -gnat2020 support, but I'm not
sure how the list wants to handle a solution.

emacs-27.1
ada-mode-7.1.4
gnat-10.2.1

$ ./build.sh
...
gen_run_wisi_lr_parse.ads:27:52: missing ";"
gen_run_wisi_lr_parse.ads:27:65: generic private child packages not permitted
gen_run_wisi_lr_parse.ads:27:65: subprogram specification expected
gen_run_wisi_lr_parse.ads:27:65: compilation unit expected
gen_run_wisi_lr_parse.ads:34:04: misplaced "with"
gen_run_wisi_lr_parse.ads:34:09: reserved word "procedure" cannot be used as 
identifier
gen_run_wisi_lr_parse.ads:34:18: missing ";"
gen_run_wisi_lr_parse.ads:34:19: compilation unit expected
clang-10: error: argument unused during compilation: 
'-specs=/tmp/GNAT-TEMP-000012.TMP' [-Werror,-Wunused-command-line-argument]

   compilation of ada_mode_wisi_lalr_parse.ads failed
   compilation of ada_mode_wisi_lr1_parse.ads failed
   compilation of run_ada_lalr_parse.ads failed
   compilation of run_ada_lr1_parse.ads failed
   compilation of gpr_mode_wisi_parse.ads failed
   compilation of run_gpr_parse.ads failed
   compilation of wisitoken_grammar_re2c.c failed

gprbuild: *** compilation phase failed

It is choking on the line:
type Parse_Data_Type is new Wisi.Parse_Data_Type with private;

As far as I can tell from the ARM, this should be legal in 2020 and 2012.
Also note the clang error. Trying with some options.

$ ./build -cargs:ada -gnat2012 -cargs:c -Wno-error=unused-command-line-argument
...
Compile
   [Ada]          ada_mode_wisi_lalr_parse.ads
   [Ada]          ada_mode_wisi_lr1_parse.ads
   [Ada]          run_ada_lalr_parse.ads
   [Ada]          run_ada_lr1_parse.ads
   [Ada]          gpr_mode_wisi_parse.ads
   [Ada]          run_gpr_parse.ads
   [Ada]          gpr_query.adb
   [C]            wisitoken_grammar_re2c.c
gpr_query.adb:553:19: target_name is an Ada 2020 feature
gpr_query.adb:553:22: (style) space not allowed
clang-10: warning: argument unused during compilation: 
'-specs=/tmp/GNAT-TEMP-000012.TMP' [-Wunused-command-line-argument]

   compilation of gpr_query.adb failed

And we fail again lacking a 2020 feature.