[Haskell] ~ type operator

Daniel Fischer daniel.is.fischer at googlemail.com
Fri Jun 24 11:10:19 CEST 2011

On Friday 24 June 2011, 10:26:42, Guy wrote:
> What does the ~ type operator mean? I've sometimes seen types such as (a
> ~ b) in error messages, but can't understand what GHC is trying to tell
> me.

Type equality, (a ~ b) means that a and b are the same type (rather, that 
the compiler can prove they're the same).

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