On Sun, Oct 13, 2013 at 2:14 AM, Michael Snoyman wrote:

The issue with yesod-core was an issue from the underlying hamlet package. hamlet has some internal functions which are used by the TH-generated code it produces, and those internal functions were not previously exported. With previous versions of GHC, this wasn't a problem, though 7.8 seems to have an issue with it. Is this an intended change?

I wouldn't know, porque yo no hablo el idioma del diablo llamado TH :-)