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This implements the BoxedRep proposal, refacoring the `RuntimeRep`
hierarchy from:
```haskell
data RuntimeRep = LiftedPtrRep | UnliftedPtrRep | ...
```
to
```haskell
data RuntimeRep = BoxedRep Levity | ...
data Levity = Lifted | Unlifted
```
Closes #17526.
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During the compilation of programs GHC very frequently deals with
the `Type` type, which is a synonym of `TYPE 'LiftedRep`. This patch
teaches GHC to avoid expanding the `Type` synonym (and other nullary
type synonyms) during type comparisons, saving a good amount of work.
This optimisation is described in `Note [Comparing nullary type
synonyms]`.
To maximize the impact of this optimisation, we introduce a few
special-cases to reduce `TYPE 'LiftedRep` to `Type`. See
`Note [Prefer Type over TYPE 'LiftedPtrRep]`.
Closes #17958.
Metric Decrease:
T18698b
T1969
T12227
T12545
T12707
T14683
T3064
T5631
T5642
T9020
T9630
T9872a
T13035
haddock.Cabal
haddock.base
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This was inadvertently merged.
This reverts commit 7e9debd4ceb068effe8ac81892d2cabcb8f55850.
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During the compilation of programs GHC very frequently deals with
the `Type` type, which is a synonym of `TYPE 'LiftedRep`. This patch
teaches GHC to avoid expanding the `Type` synonym (and other nullary
type synonyms) during type comparisons, saving a good amount of work.
This optimisation is described in `Note [Comparing nullary type
synonyms]`.
To maximize the impact of this optimisation, we introduce a few
special-cases to reduce `TYPE 'LiftedRep` to `Type`. See
`Note [Prefer Type over TYPE 'LiftedPtrRep]`.
Closes #17958.
Metric Decrease:
T18698b
T1969
T12227
T12545
T12707
T14683
T3064
T5631
T5642
T9020
T9630
T9872a
T13035
haddock.Cabal
haddock.base
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This patch fixes several aspects of kind inference for data type
declarations, especially data /instance/ declarations
Specifically
1. In kcConDecls/kcConDecl make it clear that the tc_res_kind argument
is only used in the H98 case; and in that case there is no result
kind signature; and hence no need for the disgusting splitPiTys in
kcConDecls (now thankfully gone).
The GADT case is a bit different to before, and much nicer.
This is what fixes #18891.
See Note [kcConDecls: kind-checking data type decls]
2. Do not look at the constructor decls of a data/newtype instance
in tcDataFamInstanceHeader. See GHC.Tc.TyCl.Instance
Note [Kind inference for data family instances]. This was a
new realisation that arose when doing (1)
This causes a few knock-on effects in the tests suite, because
we require more information than before in the instance /header/.
New user-manual material about this in "Kind inference in data type
declarations" and "Kind inference for data/newtype instance
declarations".
3. Minor improvement in kcTyClDecl, combining GADT and H98 cases
4. Fix #14111 and #8707 by allowing the header of a data instance
to affect kind inferece for the the data constructor signatures;
as described at length in Note [GADT return types] in GHC.Tc.TyCl
This led to a modest refactoring of the arguments (and argument
order) of tcConDecl/tcConDecls.
5. Fix #19000 by inverting the sense of the test in new_locs
in GHC.Tc.Solver.Canonical.canDecomposableTyConAppOK.
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Makes it possible for GHC to optimize away intermediate Generic representation
for more types.
Metric Increase:
T12227
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-------------------------
Metric Decrease:
T12425
Metric Increase:
T17516
-------------------------
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There are three problems with the current API:
1. It is hard to properly write instances for ``Quote m => m (TExp a)`` as the type is the composition
of two type constructors. Doing so in your program involves making your own newtype and
doing a lot of wrapping/unwrapping.
For example, if I want to create a language which I can either run immediately or
generate code from I could write the following with the new API. ::
class Lang r where
_int :: Int -> r Int
_if :: r Bool -> r a -> r a -> r a
instance Lang Identity where
_int = Identity
_if (Identity b) (Identity t) (Identity f) = Identity (if b then t else f)
instance Quote m => Lang (Code m) where
_int = liftTyped
_if cb ct cf = [|| if $$cb then $$ct else $$cf ||]
2. When doing code generation it is common to want to store code fragments in
a map. When doing typed code generation, these code fragments contain a
type index so it is desirable to store them in one of the parameterised
map data types such as ``DMap`` from ``dependent-map`` or ``MapF`` from
``parameterized-utils``.
::
compiler :: Env -> AST a -> Code Q a
data AST a where ...
data Ident a = ...
type Env = MapF Ident (Code Q)
newtype Code m a = Code (m (TExp a))
In this example, the ``MapF`` maps an ``Ident String`` directly to a ``Code Q String``.
Using one of these map types currently requires creating your own newtype and constantly
wrapping every quotation and unwrapping it when using a splice. Achievable, but
it creates even more syntactic noise than normal metaprogramming.
3. ``m (TExp a)`` is ugly to read and write, understanding ``Code m a`` is
easier. This is a weak reason but one everyone
can surely agree with.
Updates text submodule.
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GHC is very wishy-washy about rejecting instance declarations with
nested `forall`s or contexts that are surrounded by outermost
parentheses. This can even lead to some strange interactions with
`ScopedTypeVariables`, as demonstrated in #18240. This patch makes
GHC more consistently reject instance types with nested
`forall`s/contexts so as to prevent these strange interactions.
On the implementation side, this patch tweaks `splitLHsInstDeclTy`
and `getLHsInstDeclHead` to not look through parentheses, which can
be semantically significant. I've added a
`Note [No nested foralls or contexts in instance types]` in
`GHC.Hs.Type` to explain why. This also introduces a
`no_nested_foralls_contexts_err` function in `GHC.Rename.HsType` to
catch nested `forall`s/contexts in instance types. This function is
now used in `rnClsInstDecl` (for ordinary instance declarations) and
`rnSrcDerivDecl` (for standalone `deriving` declarations), the latter
of which fixes #18271.
On the documentation side, this adds a new
"Formal syntax for instance declaration types" section to the GHC
User's Guide that presents a BNF-style grammar for what is and isn't
allowed in instance types.
Fixes #18240. Fixes #18271.
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`GeneralizedNewtypeDeriving` is in the unique situation where it must
produce an `LHsType GhcPs` from a Core `Type`. Historically, this was
done with the `typeToLHsType` function, which walked over the entire
`Type` and attempted to construct an `LHsType` with the same overall
structure. `typeToLHsType` is quite complicated, however, and has
been the subject of numerous bugs over the years (e.g., #14579).
Luckily, there is an easier way to accomplish the same thing: the
`XHsType` constructor of `HsType`. `XHsType` bundles an `NHsCoreTy`,
which allows embedding a Core `Type` directly into an `HsType`,
avoiding the need to laboriously convert from one to another (as
`typeToLHsType` did). Moreover, renaming and typechecking an
`XHsType` is simple, since one doesn't need to do anything to a
Core `Type`...
...well, almost. For the reasons described in
`Note [Typechecking NHsCoreTys]` in `GHC.Tc.Gen.HsType`, we must
apply a substitution that we build from the local `tcl_env` type
environment. But that's a relatively modest price to pay.
Now that `GeneralizedNewtypeDeriving` uses `NHsCoreTy`, the
`typeToLHsType` function no longer has any uses in GHC, so this patch
rips it out. Some additional tweaks to `hsTypeNeedsParens` were
necessary to make the new `-ddump-deriv` output correctly
parenthesized, but other than that, this patch is quite
straightforward.
This is a mostly internal refactoring, although it is likely that
`GeneralizedNewtypeDeriving`-generated code will now need fewer
language extensions in certain situations than it did before.
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This started as a simple fix for #18321 that organically grew into a
much more sweeping refactor of how auxiliary bindings for derived
instances are handled. I have rewritten `Note [Auxiliary binders]`
in `GHC.Tc.Deriv.Generate` to explain all of the moving parts, but
the highlights are:
* Previously, the OccName of each auxiliary binding would be given
a suffix containing a hash of its package name, module name, and
parent data type to avoid name clashes. This was needlessly
complicated, so we take the more direct approach of generating
`Exact` `RdrName`s for each auxiliary binding with the same
`OccName`, but using an underlying `System` `Name` with a fresh
`Unique` for each binding. Unlike hashes, allocating new `Unique`s
does not require any cleverness and avoid name clashes all the
same...
* ...speaking of which, in order to convince the renamer that multiple
auxiliary bindings with the same `OccName` (but different
`Unique`s) are kosher, we now use `rnLocalValBindsLHS` instead of
`rnTopBindsLHS` to rename auxiliary bindings. Again, see
`Note [Auxiliary binders]` for the full story.
* I have removed the `DerivHsBind` constructor for
`DerivStuff`—which was only used for `Data.Data`-related
auxiliary bindings—and refactored `gen_Data_binds` to use
`DerivAuxBind` instead. This brings the treatment of
`Data.Data`-related auxiliary bindings in line with every other
form of auxiliary binding.
Fixes #18321.
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This is the first step towards implementation of the linear types proposal
(https://github.com/ghc-proposals/ghc-proposals/pull/111).
It features
* A language extension -XLinearTypes
* Syntax for linear functions in the surface language
* Linearity checking in Core Lint, enabled with -dlinear-core-lint
* Core-to-core passes are mostly compatible with linearity
* Fields in a data type can be linear or unrestricted; linear fields
have multiplicity-polymorphic constructors.
If -XLinearTypes is disabled, the GADT syntax defaults to linear fields
The following items are not yet supported:
* a # m -> b syntax (only prefix FUN is supported for now)
* Full multiplicity inference (multiplicities are really only checked)
* Decent linearity error messages
* Linear let, where, and case expressions in the surface language
(each of these currently introduce the unrestricted variant)
* Multiplicity-parametric fields
* Syntax for annotating lambda-bound or let-bound with a multiplicity
* Syntax for non-linear/multiple-field-multiplicity records
* Linear projections for records with a single linear field
* Linear pattern synonyms
* Multiplicity coercions (test LinearPolyType)
A high-level description can be found at
https://ghc.haskell.org/trac/ghc/wiki/LinearTypes/Implementation
Following the link above you will find a description of the changes made to Core.
This commit has been authored by
* Richard Eisenberg
* Krzysztof Gogolewski
* Matthew Pickering
* Arnaud Spiwack
With contributions from:
* Mark Barbone
* Alexander Vershilov
Updates haddock submodule.
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This patch simplifies GHC to use simple subsumption.
Ticket #17775
Implements GHC proposal #287
https://github.com/ghc-proposals/ghc-proposals/blob/master/
proposals/0287-simplify-subsumption.rst
All the motivation is described there; I will not repeat it here.
The implementation payload:
* tcSubType and friends become noticably simpler, because it no
longer uses eta-expansion when checking subsumption.
* No deeplyInstantiate or deeplySkolemise
That in turn means that some tests fail, by design; they can all
be fixed by eta expansion. There is a list of such changes below.
Implementing the patch led me into a variety of sticky corners, so
the patch includes several othe changes, some quite significant:
* I made String wired-in, so that
"foo" :: String rather than
"foo" :: [Char]
This improves error messages, and fixes #15679
* The pattern match checker relies on knowing about in-scope equality
constraints, andd adds them to the desugarer's environment using
addTyCsDs. But the co_fn in a FunBind was missed, and for some reason
simple-subsumption ends up with dictionaries there. So I added a
call to addTyCsDs. This is really part of #18049.
* I moved the ic_telescope field out of Implication and into
ForAllSkol instead. This is a nice win; just expresses the code
much better.
* There was a bug in GHC.Tc.TyCl.Instance.tcDataFamInstHeader.
We called checkDataKindSig inside tc_kind_sig, /before/
solveEqualities and zonking. Obviously wrong, easily fixed.
* solveLocalEqualitiesX: there was a whole mess in here, around
failing fast enough. I discovered a bad latent bug where we
could successfully kind-check a type signature, and use it,
but have unsolved constraints that could fill in coercion
holes in that signature -- aargh.
It's all explained in Note [Failure in local type signatures]
in GHC.Tc.Solver. Much better now.
* I fixed a serious bug in anonymous type holes. IN
f :: Int -> (forall a. a -> _) -> Int
that "_" should be a unification variable at the /outer/
level; it cannot be instantiated to 'a'. This was plain
wrong. New fields mode_lvl and mode_holes in TcTyMode,
and auxiliary data type GHC.Tc.Gen.HsType.HoleMode.
This fixes #16292, but makes no progress towards the more
ambitious #16082
* I got sucked into an enormous refactoring of the reporting of
equality errors in GHC.Tc.Errors, especially in
mkEqErr1
mkTyVarEqErr
misMatchMsg
misMatchMsgOrCND
In particular, the very tricky mkExpectedActualMsg function
is gone.
It took me a full day. But the result is far easier to understand.
(Still not easy!) This led to various minor improvements in error
output, and an enormous number of test-case error wibbles.
One particular point: for occurs-check errors I now just say
Can't match 'a' against '[a]'
rather than using the intimidating language of "occurs check".
* Pretty-printing AbsBinds
Tests review
* Eta expansions
T11305: one eta expansion
T12082: one eta expansion (undefined)
T13585a: one eta expansion
T3102: one eta expansion
T3692: two eta expansions (tricky)
T2239: two eta expansions
T16473: one eta
determ004: two eta expansions (undefined)
annfail06: two eta (undefined)
T17923: four eta expansions (a strange program indeed!)
tcrun035: one eta expansion
* Ambiguity check at higher rank. Now that we have simple
subsumption, a type like
f :: (forall a. Eq a => Int) -> Int
is no longer ambiguous, because we could write
g :: (forall a. Eq a => Int) -> Int
g = f
and it'd typecheck just fine. But f's type is a bit
suspicious, and we might want to consider making the
ambiguity check do a check on each sub-term. Meanwhile,
these tests are accepted, whereas they were previously
rejected as ambiguous:
T7220a
T15438
T10503
T9222
* Some more interesting error message wibbles
T13381: Fine: one error (Int ~ Exp Int)
rather than two (Int ~ Exp Int, Exp Int ~ Int)
T9834: Small change in error (improvement)
T10619: Improved
T2414: Small change, due to order of unification, fine
T2534: A very simple case in which a change of unification order
means we get tow unsolved constraints instead of one
tc211: bizarre impredicative tests; just accept this for now
Updates Cabal and haddock submodules.
Metric Increase:
T12150
T12234
T5837
haddock.base
Metric Decrease:
haddock.compiler
haddock.Cabal
haddock.base
Merge note: This appears to break the
`UnliftedNewtypesDifficultUnification` test. It has been marked as
broken in the interest of merging.
(cherry picked from commit 66b7b195cb3dce93ed5078b80bf568efae904cc5)
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As noted in !3132, this has rather severe knock-on consequences in
user-code. We'll need to revisit this before merging something along
these lines.
This reverts commit 9749fe1223d182b1f8e7e4f7378df661c509f396.
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Previously, `isTauTy` would only detect higher-rank `forall`s, not
higher-rank contexts, which led to some minor bugs observed
in #18127. Easily fixed by adding a case for
`(FunTy InvisArg _ _)`.
Fixes #18127.
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See `Note [Associated data family instances and di_scoped_tvs]` in
`GHC.Tc.TyCl.Instance`, which explains all of the moving parts.
Fixes #18055.
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Instead of using `nlHsTyVar`, which hardcodes `NotPromoted`, have
`typeToLHsType` pick between `Promoted` and `NotPromoted` by checking
if a type constructor is promoted using `isPromotedDataCon`.
Fixes #18020.
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Update Haddock submodule
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Issue #17880 demonstrates that `DeriveFunctor`-generated code is
surprisingly fragile when rank-_n_ types are involved. The culprit is
that `$fmap` (the algorithm used to generate `fmap` implementations)
was too keen on applying arguments with rank-_n_ types to lambdas,
which fail to typecheck more often than not.
In this patch, I change `$fmap` (both the specification and the
implementation) to produce code that avoids creating as many lambdas,
avoiding problems when rank-_n_ field types arise.
See the comments titled "Functor instances" in `TcGenFunctor` for a
more detailed description. Not only does this fix #17880, but it also
ensures that the code that `DeriveFunctor` generates will continue
to work after simplified subsumption is implemented (see #17775).
What is truly amazing is that #17880 is actually a regression
(introduced in GHC 7.6.3) caused by commit
49ca2a37bef18aa57235ff1dbbf1cc0434979b1e, the fix #7436. Prior to
that commit, the version of `$fmap` that was used was almost
identical to the one used in this patch! Why did that commit change
`$fmap` then? It was to avoid severe performance issues that would
arise for recursive `fmap` implementations, such as in the example
below:
```hs
data List a = Nil | Cons a (List a) deriving Functor
-- ===>
instance Functor List where
fmap f Nil = Nil
fmap f (Cons x xs) = Cons (f x) (fmap (\y -> f y) xs)
```
The fact that `\y -> f y` was eta expanded caused significant
performance overheads. Commit
49ca2a37bef18aa57235ff1dbbf1cc0434979b1e fixed this performance
issue, but it went too far. As a result, this patch partially
reverts 49ca2a37bef18aa57235ff1dbbf1cc0434979b1e.
To ensure that the performance issues pre-#7436 do not resurface,
I have taken some precautionary measures:
* I have added a special case to `$fmap` for situations where the
last type variable in an application of some type occurs directly.
If this special case fires, we avoid creating a lambda expression.
This ensures that we generate
`fmap f (Cons x xs) = Cons (f x) (fmap f xs)` in the derived
`Functor List` instance above. For more details, see
`Note [Avoid unnecessary eta expansion in derived fmap implementations]`
in `TcGenFunctor`.
* I have added a `T7436b` test case to ensure that the performance
of this derived `Functor List`-style code does not regress.
When implementing this, I discovered that `$replace`, the algorithm
which generates implementations of `(<$)`, has a special case that is
very similar to the `$fmap` special case described above. `$replace`
marked this special case with a custom `Replacer` data type, which
was a bit overkill. In order to use the same machinery for both
`Functor` methods, I ripped out `Replacer` and instead implemented
a simple way to detect the special case. See the updated commentary
in `Note [Deriving <$]` for more details.
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Aside from making the generated code easier to read when
`-ddump-deriv` is enabled, this makes the error message in `T15073`
substantially simpler (see the updated `T15073` expected stderr).
Fixes #17899.
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This brings the pretty-printer for Core in line with how visible
type applications are normally printed: namely, with no whitespace
after the `@` character (i.e., `f @a` instead of `f @ a`). While I'm
in town, I also give the same treatment to type abstractions (i.e.,
`\(@a)` instead of `\(@ a)`) and coercion applications (i.e.,
`f @~x` instead of `f @~ x`).
Fixes #17643.
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This makes error messages a tad less noisy.
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Previously, we checked all imported type family equations
for injectivity. This is very silly. Now, we check only
for conflicts.
Before I could even imagine doing the fix, I needed to untangle
several functions that were (in my opinion) overly complicated.
It's still not quite as perfect as I'd like, but it's good enough
for now.
Test case: typecheck/should_compile/T17405
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Due to the way `DerivEnv` is currently structured, there is an
invariant that every derived instance must consist of a class applied
to a non-empty list of argument types, where the last argument *must*
be an application of a type constructor to some arguments. This works
for many cases, but there are also some design patterns in standalone
`anyclass`/`via` deriving that are made impossible due to enforcing
this invariant, as documented in #13154.
This fixes #13154 by refactoring `TcDeriv` and friends to perform
fewer validity checks when using the `anyclass` or `via` strategies.
The highlights are as followed:
* Five fields of `DerivEnv` have been factored out into a new
`DerivInstTys` data type. These fields only make sense for
instances that satisfy the invariant mentioned above, so
`DerivInstTys` is now only used in `stock` and `newtype` deriving,
but not in other deriving strategies.
* There is now a `Note [DerivEnv and DerivSpecMechanism]` describing
the bullet point above in more detail, as well as explaining the
exact requirements that each deriving strategy imposes.
* I've refactored `mkEqnHelp`'s call graph to be slightly less
complicated. Instead of the previous `mkDataTypeEqn`/`mkNewTypeEqn`
dichotomy, there is now a single entrypoint `mk_eqn`.
* Various bits of code were tweaked so as not to use fields that are
specific to `DerivInstTys` so that they may be used by all deriving
strategies, since not all deriving strategies use `DerivInstTys`.
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Issue #17339 was caused by using a slightly different version of
`newDFunName` for derived instances that, confusingly enough, did not
take all arguments to the class into account when generating the
`DFun` name. I cannot think of any good reason for doing this, so
this patch uses `newDFunName` uniformly for both derived instances
and manually written instances alike.
Fixes #17339.
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If you derive an instance like this:
```hs
deriving <...> instance Foo C
```
And the data constructors for `C` aren't in scope, then
`doDerivInstErrorChecks1` throws an error. Moreover, it will
_only_ throw an error if `<...>` is either `stock` or `newtype`.
This is because the code that the `anyclass` or `via` strategies
would generate would not require the use of the data constructors
for `C`.
However, `doDerivInstErrorChecks1` has another purpose. If you
write this:
```hs
import M (C(MkC1, ..., MkCn))
deriving <...> instance Foo C
```
Then `doDerivInstErrorChecks1` will call `addUsedDataCons` on
`MkC1` through `MkCn` to ensure that `-Wunused-imports` does not
complain about them. However, `doDerivInstErrorChecks1` was doing
this for _every_ deriving strategy, which mean that if `<...>` were
`anyclass` or `via`, then the warning about `MkC1` through `MkCn`
being unused would be suppressed!
The fix is simple enough: only call `addUsedDataCons` when the
strategy is `stock` or `newtype`, just like the other code paths
in `doDerivInstErrorChecks1`.
Fixes #17324.
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The `Ix` class seems rather orthogonal to its original home in
`GHC.Arr`.
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Enabling both DeriveAnyClass and GeneralizedNewtypeDeriving can cause
a warning when no explicit deriving strategy is in use. This change adds
an enable/suppress flag for it.
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GHC used to reject programs of this form:
```
newtype Age = MkAge Int
deriving Eq via Const Int a
```
That's because an earlier implementation of `DerivingVia` would
generate the following instance:
```
instance Eq Age where
(==) = coerce @(Const Int a -> Const Int a -> Bool)
@(Age -> Age -> Bool)
(==)
```
Note that the `a` in `Const Int a` is not bound anywhere, which
causes all sorts of issues. I figured that no one would ever want to
write code like this anyway, so I simply banned "floating" `via` type
variables like `a`, checking for their presence in the aptly named
`reportFloatingViaTvs` function.
`reportFloatingViaTvs` ended up being implemented in a subtly
incorrect way, as #15831 demonstrates. Following counsel with the
sage of gold fire, I decided to abandon `reportFloatingViaTvs`
entirely and opt for a different approach that would _accept_
the instance above. This is because GHC now generates this instance
instead:
```
instance forall a. Eq Age where
(==) = coerce @(Const Int a -> Const Int a -> Bool)
@(Age -> Age -> Bool)
(==)
```
Notice that we now explicitly quantify the `a` in
`instance forall a. Eq Age`, so everything is peachy scoping-wise.
See `Note [Floating `via` type variables]` in `TcDeriv` for the full
scoop.
A pleasant benefit of this refactoring is that it made it much easier
to catch the problem observed in #16181, so this patch fixes that
issue too.
Fixes #15831. Fixes #16181.
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Otherwise the unique counter starts at 0, causing us to immediately
underflow.
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Previously, GHC would typecheck the `via` type once per class in a
`deriving` clause, which caused the problems observed in #16923.
This patch restructures some of the functionality in `TcDeriv` and
`TcHsType` to avoid this problem. We now typecheck the `via` type
exactly once per `deriving` clause and *then* typecheck all of the
classes in the clause.
See `Note [Don't typecheck too much in DerivingVia]` in `TcDeriv`
for the full details.
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Before this refactoring:
* DerivInfo for data family instances was returned from tcTyAndClassDecls
* DerivInfo for data declarations was generated with mkDerivInfos and added at a
later stage of the pipeline in tcInstDeclsDeriv
After this refactoring:
* DerivInfo for both data family instances and data declarations is returned from
tcTyAndClassDecls in a single list.
This uniform treatment results in a more convenient arrangement to fix #16731.
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* Tweak the parser to allow `deriving` clauses to mention explicit
`forall`s or kind signatures without gratuitous parentheses.
(This fixes #14332 as a consequence.)
* Allow Haddock comments on `deriving` clauses with explicit
`forall`s. This requires corresponding changes in Haddock.
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Besides the obvious benefits of being able to manipulate `TExp`'s of
unboxed types, this also simplified `-XDeriveLift` all while making
it more capable.
* `ghc-prim` is explicitly depended upon by `template-haskell`
* The following TH things are parametrized over `RuntimeRep`:
- `TExp(..)`
- `unTypeQ`
- `unsafeTExpCoerce`
- `Lift(..)`
* The following instances have been added to `Lift`:
- `Int#`, `Word#`, `Float#`, `Double#`, `Char#`, `Addr#`
- unboxed tuples of lifted types up to arity 7
- unboxed sums of lifted types up to arity 7
Ideally we would have levity-polymorphic _instances_ of unboxed
tuples and sums.
* The code generated by `-XDeriveLift` uses expression quotes
instead of generating large amounts of TH code and having
special hard-coded cases for some unboxed types.
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This patch corrects two simple oversights that led to #16518:
1. `HsUtils.typeToLHsType` was taking visibility into account in the
`TyConApp` case, but not the `AppTy` case. I've factored out the
visibility-related logic into its own `go_app` function and now
invoke `go_app` from both the `TyConApp` and `AppTy` cases.
2. `Type.fun_kind_arg_flags` did not properly split kinds with
nested `forall`s, such as
`(forall k. k -> Type) -> (forall k. k -> Type)`. This was simply
because `fun_kind_arg_flags`'s `FunTy` case always bailed out and
assumed all subsequent arguments were `Required`, which clearly
isn't the case for nested `forall`s. I tweaked the `FunTy` case
to recur on the result kind.
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This moves all URL references to Trac Wiki to their corresponding
GitLab counterparts.
This substitution is classified as follows:
1. Automated substitution using sed with Ben's mapping rule [1]
Old: ghc.haskell.org/trac/ghc/wiki/XxxYyy...
New: gitlab.haskell.org/ghc/ghc/wikis/xxx-yyy...
2. Manual substitution for URLs containing `#` index
Old: ghc.haskell.org/trac/ghc/wiki/XxxYyy...#Zzz
New: gitlab.haskell.org/ghc/ghc/wikis/xxx-yyy...#zzz
3. Manual substitution for strings starting with `Commentary`
Old: Commentary/XxxYyy...
New: commentary/xxx-yyy...
See also !539
[1]: https://gitlab.haskell.org/bgamari/gitlab-migration/blob/master/wiki-mapping.json
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This moves all URL references to Trac tickets to their corresponding
GitLab counterparts.
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Implements GHC proposal 43, adding a `liftTyped` method to the `Lift` typeclass.
This also adds some documentation to `TExp`, describing typed splices and their
advantages over their untyped counterparts.
Resolves #14671.
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This eliminates most uses of run_command in the testsuite in favor of the more
structured makefile_test.
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This reverts commit 76c8fd674435a652c75a96c85abbf26f1f221876.
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Summary:
When DeriveAnyClass and GeneralizedNewtypeDeriving are both enabled,
GHC prints out a warning that specifies the strategy it used to
derive a class. This patch updates the warning to mention that users
may pick a particular strategy by using DerivingStrategies.
Test plan: make test TEST=T16179
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Summary:
This patch implements visible kind application (GHC Proposal 15/#12045), as well as #15360 and #15362.
It also refactors unnamed wildcard handling, and requires that type equations in type families in Template Haskell be
written with full type on lhs. PartialTypeSignatures are on and warnings are off automatically with visible kind
application, just like in term-level.
There are a few remaining issues with this patch, as documented in
ticket #16082.
Includes a submodule update for Haddock.
Test Plan: Tests T12045a/b/c/TH1/TH2, T15362, T15592a
Reviewers: simonpj, goldfire, bgamari, alanz, RyanGlScott, Iceland_jack
Subscribers: ningning, Iceland_jack, RyanGlScott, int-index, rwbarton, mpickering, carter
GHC Trac Issues: `#12045`, `#15362`, `#15592`, `#15788`, `#15793`, `#15795`, `#15797`, `#15799`, `#15801`, `#15807`, `#15816`
Differential Revision: https://phabricator.haskell.org/D5229
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This patch makes the following improvement:
- Automatically records test metrics (per test environment) so that
the programmer need not supply nor update expected values in *.T
files.
- On expected metric changes, the programmer need only indicate the
direction of change in the git commit message.
- Provides a simple python tool "perf_notes.py" to compare metrics
over time.
Issues:
- Using just the previous commit allows performance to drift with each
commit.
- Currently we allow drift as we have a preference for minimizing
false positives.
- Some possible alternatives include:
- Use metrics from a fixed commit per test: the last commit that
allowed a change in performance (else the oldest metric)
- Or use some sort of aggregate since the last commit that allowed
a change in performance (else all available metrics)
- These alternatives may result in a performance issue (with the
test driver) having to heavily search git commits/notes.
- Run locally, performance tests will trivially pass unless the tests
were run locally on the previous commit. This is often not the case
e.g. after pulling recent changes.
Previously, *.T files contain statements such as:
```
stats_num_field('peak_megabytes_allocated', (2, 1))
compiler_stats_num_field('bytes allocated',
[(wordsize(64), 165890392, 10)])
```
This required the programmer to give the expected values and a tolerance
deviation (percentage). With this patch, the above statements are
replaced with:
```
collect_stats('peak_megabytes_allocated', 5)
collect_compiler_stats('bytes allocated', 10)
```
So that programmer must only enter which metrics to test and a tolerance
deviation. No expected value is required. CircleCI will then run the
tests per test environment and record the metrics to a git note for that
commit and push them to the git.haskell.org ghc repo. Metrics will be
compared to the previous commit. If they are different by the tolerance
deviation from the *.T file, then the corresponding test will fail. By
adding to the git commit message e.g.
```
# Metric (In|De)crease <metric(s)> <options>: <tests>
Metric Increase ['bytes allocated', 'peak_megabytes_allocated'] \
(test_env='linux_x86', way='default'):
Test012, Test345
Metric Decrease 'bytes allocated':
Test678
Metric Increase:
Test711
```
This will allow the noted changes (letting the test pass). Note that by
omitting metrics or options, the change will apply to all possible
metrics/options (i.e. in the above, an increase for all metrics in all
test environments is allowed for Test711)
phabricator will use the message in the description
Reviewers: bgamari, hvr
Reviewed By: bgamari
Subscribers: rwbarton, carter
GHC Trac Issues: #12758
Differential Revision: https://phabricator.haskell.org/D5059
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