Dune environment variables suppressing compiler warnings

[MartyO256]

The following dune environment variables are set in the core, harpoon and optparser packages.
These globally disable compilation warnings such as unused variables.
However, what I find alarming is that warnings about not exhaustive pattern-matching are also suppressed.
This explains why there are not easily reproducible pattern-matching errors thrown in Harpoon sessions.

Beluga/src/core/dune

Lines 7 to 9 in 3db1ffd

	(env
	(dev
	(flags (:standard -w Azep-44-48-50-58 -warn-error Ap-37-48-50-60))))

Beluga/src/harpoon/dune

Lines 6 to 8 in 3db1ffd

	(env
	(dev
	(flags (:standard -w Azep-44-48-50-58 -warn-error Ap-37-48-50-60))))

Beluga/src/optparser/dune

Lines 3 to 5 in 3db1ffd

	(env
	(dev
	(flags (:standard -w A-42-44 -warn-error A-42-44))))

Where not exhaustive pattern-matching is intended as in the following, then warnings should be explicitly suppressed with macros like [@warning "-8"] instead of being toggled off globally.

Beluga/src/core/error.ml

Lines 116 to 122 in 3db1ffd

	begin fun (Sys_error msg) ->
	print
	begin fun ppf ->
	Format.fprintf ppf "System error: %s"
	msg
	end
	end;

Fixing this issue won't be easy as it affects most files.

[Ailrun]

There's really a lot of non-exhaustive pattern matches, so it's hard to enable the warning. An affordable solution would be handling them one-by-one (though it will still take long time)