Re: [Haskell-cafe] ghc should be able to deduce correct use of partial functions and not give a warning in such cases

On Tue, 16 Apr 2024, George Colpitts wrote:

ghc should be able to deduce correct use of partial functions and not give a warning in such cases, e.g. in 9.8.2

     if null ys then [] else [(xs,tail ys)])

gets a warning

      warning: [GHC-63394] [-Wx-partial]

but it is clear that this use of tail will never be a problem so IMHO that line of code should not get a warning. 

Does anybody know if there is a plan or enhancement request to eliminate such warnings? 

I would just use good old pattern matching: case ys of [] -> [] _:zs -> [(xs,zs)]