id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
1231	deprecation warnings are reported too often	malcolm.wallace@…	simonpj	"Not so much a bug, more an annoyance.

In some code which is designed to work on multiple compiler platforms, there are some system dependencies such as the name/location of non-standard libraries.  Accordingly, I gather all such deps into a single module SysDeps.hs, which is heavily reliant on cpp #ifdefs, but whose only purpose is to re-export the non-standard entities needed by the rest of the project.  So far so good.  Now it turns out that ghc-6.6 has deprecated some of the non-standard libraries.  Fair enough, I would expect to see the deprecation warnings when I compile SysDeps.hs.  But in fact, I see multiple deprecation warnings - one for every deprecated entity, used in any module.  So instead of seeing 5 or so warnings, nicely localised to a single module, I see 40 or so, smeared out across the whole project.

An example:
{{{
Import.hs:9:28:
    Warning: Deprecated use of `unpackPS'
	     (imported from SysDeps, but defined in Data.PackedString):
	     use Data.ByteString, Data.ByteString.Char8, or plain String.
}}}

As you can see, the warning mechanism is aware that it is doing a transitive closure over imports.  But really, I'd prefer it not to, and instead to report the deprecation only in the directly-importing module."	feature request	new	low	_|_	Compiler	6.6				Unknown/Multiple	Unknown/Multiple	None/Unknown	Unknown	nhc98/src/compiler98