"Found hole"

Stephen Paul Weber singpolyma at singpolyma.net
Wed Jan 21 14:53:50 UTC 2015

>The leading underscore invokes the typed holes extension. If you want to
>use such names, you'll need {-# LANGUAGE NoTypedHoles #-} as the first line
>of the source file. (I am not sure why this extension was enabled by

This is very concening for me.  Extensions should *never* be enabled by 
default!  When the TypedHoles discussion originally came up there was 
definitely talk of using a switch to enable them (in fact, IIRC, they 
weren't originally really quite an extension, just a compiler mode, but that 
may have been a misinterpretation on my part).

Having them on by default mean that valid Haskell2010 programs might get 
rejected by GHC by default, which is a pretty bad state of affairs.

Stephen Paul Weber, @singpolyma
See <http://singpolyma.net> for how I prefer to be contacted
edition right joseph
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