[Haskell-cafe] Redundant/overlapping patterns?

[Todd Wilson]

Hi, Cafe,

Can someone please explain this:

ghci> case 1 of 2 -> 3

<interactive>:1:11: warning: [-Woverlapping-patterns]
    Pattern match is redundant
    In a case alternative: 2 -> ...
*** Exception: <interactive>:1:1-16: Non-exhaustive patterns in case

The non-exhaustive patterns part is obvious, but what is redundant about
this match? And how can there be overlapping patterns when there's only one?

Todd Wilson
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