Commit a1fc7ce3 authored by Simon Peyton Jones's avatar Simon Peyton Jones

Comments only

parent a4ee2897
......@@ -897,21 +897,22 @@ tagToEnumRule = do
_ -> WARN( True, text "tagToEnum# on non-enumeration type" <+> ppr ty )
return $ mkRuntimeErrorApp rUNTIME_ERROR_ID ty "tagToEnum# on non-enumeration type"
{-
For dataToTag#, we can reduce if either
(a) the argument is a constructor
(b) the argument is a variable whose unfolding is a known constructor
-}
------------------------------
dataToTagRule :: RuleM CoreExpr
-- Rules for dataToTag#
dataToTagRule = a `mplus` b
where
-- dataToTag (tagToEnum x) ==> x
a = do
[Type ty1, Var tag_to_enum `App` Type ty2 `App` tag] <- getArgs
guard $ tag_to_enum `hasKey` tagToEnumKey
guard $ ty1 `eqType` ty2
return tag -- dataToTag (tagToEnum x) ==> x
return tag
-- dataToTag (K e1 e2) ==> tag-of K
-- This also works (via exprIsConApp_maybe) for
-- dataToTag x
-- where x's unfolding is a constructor application
b = do
dflags <- getDynFlags
[_, val_arg] <- getArgs
......
......@@ -182,7 +182,7 @@ If we have
where f is strict in y, we might get a more efficient loop by w/w'ing
f. But that would make a new unfolding which would overwrite the old
one! So the function would no longer be ININABLE, and in particular
one! So the function would no longer be INLNABLE, and in particular
will not be specialised at call sites in other modules.
This comes in practice (Trac #6056).
......
......@@ -3002,7 +3002,7 @@ checkValidRoleAnnots role_annots tc
; _ <- zipWith3M checkRoleAnnot vis_vars the_role_annots vis_roles
-- Representational or phantom roles for class parameters
-- quickly lead to incoherence. So, we require
-- IncoherentInstances to have them. See #8773.
-- IncoherentInstances to have them. See #8773, #14292
; incoherent_roles_ok <- xoptM LangExt.IncoherentInstances
; checkTc ( incoherent_roles_ok
|| (not $ isClassTyCon tc)
......
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