Fix a few loose ends from D1795

George updated the Diff but I didn't noticed until it was too late.

(cherry picked from commit bbc0ec57)

compiler/deSugar/Check.hs

@@ -1272,7 +1272,7 @@ warnPmIters dflags (DsMatchContext kind loc)
     ctxt   = pprMatchContext kind
     msg is = fsep [ text "Pattern match checker exceeded"
                   , parens (ppr is), text "iterations in", ctxt <> dot
-                  , text "(Use fmax-pmcheck-iterations=n"
+                  , text "(Use -fmax-pmcheck-iterations=n"
                   , text "to set the maximun number of iterations to n)" ]
 
     flag_i = wopt Opt_WarnOverlappingPatterns dflags

compiler/deSugar/DsMonad.hs

@@ -362,9 +362,6 @@ addTmCsDs :: Bag SimpleEq -> DsM a -> DsM a
 addTmCsDs tm_cs
   = updLclEnv (\env -> env { dsl_tm_cs = unionBags tm_cs (dsl_tm_cs env) })
 
--- | Check that we have not done more iterations
--- than we are supposed to and inrease the counter
-
 -- | Increase the counter for elapsed pattern match check iterations.
 -- If the current counter is already over the limit, fail
 incrCheckPmIterDs :: DsM ()

docs/users_guide/8.0.1-notes.rst

@@ -279,6 +279,14 @@ Compiler
    warns in the case of unused term-level patterns. Both flags are implied by
    :ghc-flag:`-W`.
 
+-  Added the :ghc-flag:`-fmax-pmcheck-iterations` to control how many times
+   the pattern match checker iterates. Since coverage checking is exponential
+   in the general case, setting a default number of iterations prevents memory
+   and performance blowups. By default, the number of iterations is set to
+   10000000 but it can be set to ``n`` with: ``-fmax-pmcheck-iterations=n``.
+   If the set number of iterations is exceeded, an informative warning is
+   issued.
+
 -  :ghc-flag:`-this-package-key` has been renamed again (hopefully for the last time!)
    to :ghc-flag:`-this-unit-id`.  The renaming was motivated by the fact that
    the identifier you pass to GHC here doesn't have much to do with packages: