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| author | Andrew Martin <andrew.thaddeus@gmail.com> | 2019-05-12 09:23:25 -0400 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-06-14 10:48:13 -0400 |
| commit | effdd948056923f3bc03688c24d7e0339d6272f5 (patch) | |
| tree | 02a3cb68ce1680db89c8440ba8beea808cbf4a11 /testsuite/tests/typecheck/should_fail/tcfail140.stderr | |
| parent | 3bc6df3223f62a8366e2e4267bac23aa08e6a939 (diff) | |
| download | haskell-effdd948056923f3bc03688c24d7e0339d6272f5.tar.gz | |
Implement the -XUnliftedNewtypes extension.
GHC Proposal: 0013-unlifted-newtypes.rst
Discussion: https://github.com/ghc-proposals/ghc-proposals/pull/98
Issues: #15219, #1311, #13595, #15883
Implementation Details:
Note [Implementation of UnliftedNewtypes]
Note [Unifying data family kinds]
Note [Compulsory newtype unfolding]
This patch introduces the -XUnliftedNewtypes extension. When this
extension is enabled, GHC drops the restriction that the field in
a newtype must be of kind (TYPE 'LiftedRep). This allows types
like Int# and ByteArray# to be used in a newtype. Additionally,
coerce is made levity-polymorphic so that it can be used with
newtypes over unlifted types.
The bulk of the changes are in TcTyClsDecls.hs. With -XUnliftedNewtypes,
getInitialKind is more liberal, introducing a unification variable to
return the kind (TYPE r0) rather than just returning (TYPE 'LiftedRep).
When kind-checking a data constructor with kcConDecl, we attempt to
unify the kind of a newtype with the kind of its field's type. When
typechecking a data declaration with tcTyClDecl, we again perform a
unification. See the implementation note for more on this.
Co-authored-by: Richard Eisenberg <rae@richarde.dev>
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/tcfail140.stderr')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/tcfail140.stderr | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/testsuite/tests/typecheck/should_fail/tcfail140.stderr b/testsuite/tests/typecheck/should_fail/tcfail140.stderr index 85217315ca..924e14081b 100644 --- a/testsuite/tests/typecheck/should_fail/tcfail140.stderr +++ b/testsuite/tests/typecheck/should_fail/tcfail140.stderr @@ -1,7 +1,6 @@ tcfail140.hs:10:7: error: - • Couldn't match expected type ‘Integer -> t’ - with actual type ‘Int’ + • Couldn't match expected type ‘t0 -> t’ with actual type ‘Int’ • The function ‘f’ is applied to two arguments, but its type ‘Int -> Int’ has only one In the expression: f 3 9 @@ -9,8 +8,7 @@ tcfail140.hs:10:7: error: • Relevant bindings include bar :: t (bound at tcfail140.hs:10:1) tcfail140.hs:12:10: error: - • Couldn't match expected type ‘Integer -> t’ - with actual type ‘Int’ + • Couldn't match expected type ‘t1 -> t’ with actual type ‘Int’ • The operator ‘f’ takes two arguments, but its type ‘Int -> Int’ has only one In the expression: 3 `f` 4 |