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author | Simon Peyton Jones <simonpj@microsoft.com> | 2016-06-15 13:27:12 +0100 |
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committer | Simon Peyton Jones <simonpj@microsoft.com> | 2016-06-15 17:36:02 +0100 |
commit | e368f3265b80aeb337fbac3f6a70ee54ab14edfd (patch) | |
tree | c38b396e267a5f8172751daa8f985c22d6f92760 /testsuite/tests/typecheck/should_fail/tcfail033.stderr | |
parent | 77bb09270c70455bbd547470c4e995707d19f37d (diff) | |
download | haskell-e368f3265b80aeb337fbac3f6a70ee54ab14edfd.tar.gz |
Major patch to introduce TyConBinder
Before this patch, following the TypeInType innovations,
each TyCon had two lists:
- tyConBinders :: [TyBinder]
- tyConTyVars :: [TyVar]
They were in 1-1 correspondence and contained
overlapping information. More broadly, there were many
places where we had to pass around this pair of lists,
instead of a single list.
This commit tidies all that up, by having just one list of
binders in a TyCon:
- tyConBinders :: [TyConBinder]
The new data types look like this:
Var.hs:
data TyVarBndr tyvar vis = TvBndr tyvar vis
data VisibilityFlag = Visible | Specified | Invisible
type TyVarBinder = TyVarBndr TyVar VisibilityFlag
TyCon.hs:
type TyConBinder = TyVarBndr TyVar TyConBndrVis
data TyConBndrVis
= NamedTCB VisibilityFlag
| AnonTCB
TyCoRep.hs:
data TyBinder
= Named TyVarBinder
| Anon Type
Note that Var.TyVarBdr has moved from TyCoRep and has been
made polymorphic in the tyvar and visiblity fields:
type TyVarBinder = TyVarBndr TyVar VisibilityFlag
-- Used in ForAllTy
type TyConBinder = TyVarBndr TyVar TyConBndrVis
-- Used in TyCon
type IfaceForAllBndr = TyVarBndr IfaceTvBndr VisibilityFlag
type IfaceTyConBinder = TyVarBndr IfaceTvBndr TyConBndrVis
-- Ditto, in interface files
There are a zillion knock-on changes, but everything
arises from these types. It was a bit fiddly to get the
module loops to work out right!
Some smaller points
~~~~~~~~~~~~~~~~~~~
* Nice new functions
TysPrim.mkTemplateKiTyVars
TysPrim.mkTemplateTyConBinders
which help you make the tyvar binders for dependently-typed
TyCons. See comments with their definition.
* The change showed up a bug in TcGenGenerics.tc_mkRepTy, where the code
was making an assumption about the order of the kind variables in the
kind of GHC.Generics.(:.:). I fixed this; see TcGenGenerics.mkComp.
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/tcfail033.stderr')
-rw-r--r-- | testsuite/tests/typecheck/should_fail/tcfail033.stderr | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/testsuite/tests/typecheck/should_fail/tcfail033.stderr b/testsuite/tests/typecheck/should_fail/tcfail033.stderr index e349ab1116..bc346c2aac 100644 --- a/testsuite/tests/typecheck/should_fail/tcfail033.stderr +++ b/testsuite/tests/typecheck/should_fail/tcfail033.stderr @@ -1,10 +1,10 @@ tcfail033.hs:4:12: error: - • Occurs check: cannot construct the infinite type: t1 ~ (t1, t) + • Occurs check: cannot construct the infinite type: a ~ (a, b) • In the expression: x In the expression: [x | (x, y) <- buglet] In an equation for ‘buglet’: buglet = [x | (x, y) <- buglet] • Relevant bindings include - y :: t (bound at tcfail033.hs:4:19) - x :: t1 (bound at tcfail033.hs:4:17) - buglet :: [(t1, t)] (bound at tcfail033.hs:4:1) + y :: b (bound at tcfail033.hs:4:19) + x :: a (bound at tcfail033.hs:4:17) + buglet :: [(a, b)] (bound at tcfail033.hs:4:1) |