Richard, weren't you going to open a ticket to track this? It ought to hold!
Simon
| -----Original Message-----
| From: ghc-commits On Behalf Of
| git@git.haskell.org
| Sent: 15 July 2018 02:28
| To: ghc-commits@haskell.org
| Subject: [commit: ghc] master: Remove ASSERTion about increasing TcLevels
| (a754a42)
|
| Repository : ssh://git@git.haskell.org/ghc
|
| On branch : master
| Link :
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| ll.org%2Ftrac%2Fghc%2Fchangeset%2Fa754a420b53cd2210ef60dcd695bf3334af2e40
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| rved=0
|
| >---------------------------------------------------------------
|
| commit a754a420b53cd2210ef60dcd695bf3334af2e400
| Author: Richard Eisenberg
| Date: Thu Jul 12 16:10:34 2018 -0400
|
| Remove ASSERTion about increasing TcLevels
|
| This removes an ASSERTion that TcLevels should increase by
| exactly one in every implication. While this is a sensible
| goal, it's not true today, and we should not be crippling
| DEBUG for everyone while debugging this.
|
| The ASSERT was added in 261dd83cacec71edd551e9c581d05285c9ea3226
|
|
| >---------------------------------------------------------------
|
| a754a420b53cd2210ef60dcd695bf3334af2e400
| compiler/typecheck/TcSimplify.hs | 8 +++++++-
| 1 file changed, 7 insertions(+), 1 deletion(-)
|
| diff --git a/compiler/typecheck/TcSimplify.hs
| b/compiler/typecheck/TcSimplify.hs
| index 13a3f73..c57ef56 100644
| --- a/compiler/typecheck/TcSimplify.hs
| +++ b/compiler/typecheck/TcSimplify.hs
| @@ -1495,7 +1495,8 @@ solveImplication imp@(Implic { ic_tclvl = tclvl
| = do { inerts <- getTcSInerts
| ; traceTcS "solveImplication {" (ppr imp $$ text "Inerts" <+> ppr
| inerts)
|
| - ; when debugIsOn check_tc_level
| + -- commented out; see `where` clause below
| + -- ; when debugIsOn check_tc_level
|
| -- Solve the nested constraints
| ; (no_given_eqs, given_insols, residual_wanted)
| @@ -1544,10 +1545,15 @@ solveImplication imp@(Implic { ic_tclvl = tclvl
| -- TcLevels must be strictly increasing (see (ImplicInv) in
| -- Note [TcLevel and untouchable type variables] in TcType),
| -- and in fact I thinkthey should always increase one level at a
| time.
| +
| + -- Though sensible, this check causes lots of testsuite failures. It
| is
| + -- remaining commented out for now.
| + {-
| check_tc_level = do { cur_lvl <- TcS.getTcLevel
| ; MASSERT2( tclvl == pushTcLevel cur_lvl
| , text "Cur lvl =" <+> ppr cur_lvl $$
| text "Imp lvl =" <+> ppr tclvl ) }
| + -}
|
| ----------------------
| setImplicationStatus :: Implication -> TcS (Maybe Implication)
|
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