On Thu, Sep 22, 2011 at 7:37 AM, Heinrich Apfelmus
- foo :: Typeable a => AddHandler a -> NetworkDescription (Event a) + foo :: AddHandler a -> NetworkDescription (Event a)
Can removing a type class constraint on a function break dependent code? Should I change the B number or just the C in version A.B.C when introducing this change?
This change would break only backwards compatibility. For example, suppose that the version with "Typeable a =>" is 0.1.2 and the version without is 0.1.3. Suppose that you have already released your version 0.1.3 when I create a package with the value: bar :: NetworkDescription (Event (Set a)) bar = ... foo ... Given that you are following the PVP, I would put the following constraint: Build-depends: foo >= 0.1 && < 0.2 However, if someone with an older version of foo installed on their system tried to install my package, they would get a type error, since I haven't put a "Typeable a =>" context on my bar. So, yes, that change can break some code. Is that change big enough to be considered harmful? I don't know =), probably not. Cheers, -- Felipe.