Collect coercion variables, not type variables
authorSimon Peyton Jones <simonpj@microsoft.com>
Wed, 26 Oct 2016 13:58:59 +0000 (14:58 +0100)
committerSimon Peyton Jones <simonpj@microsoft.com>
Thu, 27 Oct 2016 07:28:33 +0000 (08:28 +0100)
commitf9308c2a682d45e061eaa169c4f2389009a9177e
treeb7b3266d151dc1c43e1bb49c6fcd072af7a835a7
parent3562727fd8a8bf5bc5aa0474a78f6c14f14f95a0
Collect coercion variables, not type variables

...when tracking which constraints are used.

Previously we were gathering type variables too, which meant that the
ics_need field was (stupidly) non-empty, which meant that we kept hold
of solved implications for no purpose.  Better just to get rid of them,
which setImplicationStatus is all ste up to to do.

No change in behaviour; a bit more efficient.
compiler/typecheck/TcEvidence.hs
compiler/typecheck/TcSMonad.hs