On Sat, 14 Jul 2012, Henning Thielemann wrote:
So I think SafeHaskell could be a way to locate problems in code faster. Since a Haskell 98 program without unsafePerformIO and friends cannot crash, a crash can be only caused by Unsafe code.
Shortly after I wrote this, I noticed that I was wrong. IO also allows you to crash in many ways. Thus I have to say: A Haskell 98 program without IO, unsafePerformIO and friends cannot crash. I first saw the UNSAFE feature in Modula-3. Modula-3 does not have referential transparent functions and does not distinguish between IO functions and non-IO functions. So what does UNSAFE mean for Modula-3? Actually, Modula-3 programs with only SAFE modules cannot crash, because pointer arithmetic and typecasts (LOOPHOLE) are only allowed in UNSAFE modules.