From 4840f19081884048dcc6c9a69d8267390bde5da9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20D=C3=ADaz=20Carrete?= Date: Thu, 31 Dec 2020 09:32:09 +0100 Subject: [PATCH] Update README.md --- lesson5-abstract-typeclasses/README.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lesson5-abstract-typeclasses/README.md b/lesson5-abstract-typeclasses/README.md index 0cabe65..3bb06e0 100644 --- a/lesson5-abstract-typeclasses/README.md +++ b/lesson5-abstract-typeclasses/README.md @@ -98,7 +98,7 @@ alas, it doesn't compile: lib/Lesson5.hs:10:13: error: • No instance for (Key Int) arising from a use of ‘{Mappy.lookup}’ -Why? Well, consider that, unlike [`Main`](./Main.hs), [`Lesson5`](./lib/Lesson5.hs) lives in an indefinite +Why? Well, consider that—unlike [`Main`](./Main.hs)—[`Lesson5`](./lib/Lesson5.hs) lives in an indefinite library. It doesn't know anything about possible implementations of `Mappy`—check its dependencies in the [`.cabal`](./package.cabal) file! Therefore, it can't be sure that `Int` has the required `Key` instance. That typeclass could be