Move to a more structured error representation

GHC spits out errors as SDocs, which makes it hard for clients of the GHC API to respond sensibly to them. (Parsing error message strings seems ... sub-optimal.) This ticket tracks progress towards improving the situation.

Key resources

The errors-as-values GHC proposal 306 describes the problem, and the proposed solution
The errors-as-values wiki page describes the high level design for how we propose to implement it in GHC.

For design discussion, use this ticket.

To track the advancement of this ticket, check out the Implementation Plan in the Wiki, which breaks it down into manageable tasks as well as listing the associated merge requests.

Edited Apr 12, 2021 by Alfredo Di Napoli

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