id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
1442	"ghc and ghci differs in deailing with ""undefined"" with I/O"	guest		"This program:
{{{
main = putStrLn (""x == "" ++ undefined)
}}}

produces the following expected output with ghci:
{{{
x == *** Exception: Prelude.undefined
}}}

but when compiled with ghc and run, it gives:
{{{
$./a.out 
a.out: Prelude.undefined
}}}

we observed this in all the way back to ghc6.2.1; possibly earlier.

The semantics of error reporting in combination with I/O is murky; admittedly laziness is observable at the top-level when errors are reported. But at least ghc and ghci should do the same thing. And the behavior of ghci seems to be more appropriate.

Thanks!

Jeff Lewis and Levent Erkok"	bug	closed	normal		Compiler	6.6.1	invalid		levent.erkok@… jeff@…	Unknown/Multiple	Unknown/Multiple		Unknown