Warn when ana.opt.hashcons is off, but witness.graphml.enabled or exp.arg.enabled are on or an Apron domain is on

[michael-schwarz]

In theses cases, counterintuitively, --disable ana.opt.hashcons doesn't completely disable hashconsing, as observed by @sim642

analyzer/src/framework/control.ml

Line 19 in f214ec5

let arg_enabled = get_bool "witness.graphml.enabled" || get_bool "exp.arg.enabled" in

analyzer/src/framework/control.ml

Lines 29 to 31 in f214ec5

	(* hashcons before witness to reduce duplicates, because witness re-uses contexts in domain and requires tag for PathSensitive3 *)
	|> lift (get_bool "ana.opt.hashcons" || arg_enabled) (module HashconsContextLifter)
	|> lift arg_enabled (module HashconsLifter)

[sim642]

As to the Apron domain use case (getting a totally-ordered compare for a type with just equal and hash), a thing to explore could also be wrapping hashconsing directly around that domain, instead of relying on some very outermost hashconsing to implement compare such that Goblint wouldn't crash outright.