No join-point from an INLINE function with wrong arity

The main payload of this patch is NOT to make a join-point
from a function with an INLINE pragma and the wrong arity;
see Note [Join points and INLINE pragmas] in CoreOpt.
This is what caused Trac #13413.

But we must do the exact same thing in simpleOptExpr,
which drove me to the following refactoring:

* Move simpleOptExpr and simpleOptPgm from CoreSubst to a new
  module CoreOpt along with a few others (exprIsConApp_maybe,
  pushCoArg, etc)

  This eliminates a module loop altogether (delete
  CoreArity.hs-boot), and stops CoreSubst getting too huge.

* Rename Simplify.matchOrConvertToJoinPoint
     to joinPointBinding_maybe
  Move it to the new CoreOpt
  Use it in simpleOptExpr as well as in Simplify

* Define CoreArity.joinRhsArity and use it

1 files changed, 1 insertions, 0 deletions

diff --git a/compiler/specialise/Rules.hs b/compiler/specialise/Rules.hs
index 47193c66bc..192b6bb212 100644
--- a/compiler/specialise/Rules.hs
+++ b/compiler/specialise/Rules.hs
@@ -31,6 +31,7 @@ module Rules (
 import CoreSyn          -- All of it
 import Module           ( Module, ModuleSet, elemModuleSet )
 import CoreSubst
+import CoreOpt          ( exprIsLambda_maybe )
 import CoreFVs          ( exprFreeVars, exprsFreeVars, bindFreeVars
                         , rulesFreeVarsDSet, exprsOrphNames, exprFreeVarsList )
 import CoreUtils        ( exprType, eqExpr, mkTick, mkTicks,