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| author | Edward Z. Yang <ezyang@cs.stanford.edu> | 2017-01-05 13:52:12 -0800 |
|---|---|---|
| committer | Edward Z. Yang <ezyang@cs.stanford.edu> | 2017-01-11 06:54:00 -0800 |
| commit | 5def07fadd386a7a7c3a12963c0736529e377a74 (patch) | |
| tree | 1b2b5dbde6f6a227c4b2faa777080b4014fc4ee6 /testsuite/tests/rename/should_fail/rnfail055.stderr | |
| parent | e41c61fa7792d12ac7ffbacda7a5b3ba6ef2a267 (diff) | |
| download | haskell-5def07fadd386a7a7c3a12963c0736529e377a74.tar.gz | |
Revamp Backpack/hs-boot handling of type class signatures.
Summary:
A basket of fixes and improvements:
- The permissible things that one can write in a type
class definition in an hsig file has been reduced
to encompass the following things:
- Methods
- Default method signatures (but NOT implementation)
- MINIMAL pragma
It is no longer necessary nor encouraged to specify
that a method has a default if it is mentioned in
a MINIMAL pragma; the MINIMAL pragma is assumed to
provide the base truth as to what methods need to
be implemented when writing instances of a type
class.
- Handling of default method signatures in hsig was
previously buggy, as these identifiers were not exported,
so we now treat them similarly to DFuns.
- Default methods are merged, where methods with defaults
override those without.
- MINIMAL pragmas are merged by ORing together pragmas.
- Matching has been relaxed: a method with a default can
be used to fill a signature which did not declare the
method as having a default, and a more relaxed MINIMAL
pragma can be used (we check if the signature pragma
implies the final implementation pragma, on the way
fixing a bug with BooleanFormula.implies, see #13073)
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Test Plan: validate
Reviewers: simonpj, bgamari, austin
Subscribers: thomie
Differential Revision: https://phabricator.haskell.org/D2925
GHC Trac Issues: #13041
Diffstat (limited to 'testsuite/tests/rename/should_fail/rnfail055.stderr')
| -rw-r--r-- | testsuite/tests/rename/should_fail/rnfail055.stderr | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/testsuite/tests/rename/should_fail/rnfail055.stderr b/testsuite/tests/rename/should_fail/rnfail055.stderr index e7e6a3a817..7fc5d80bad 100644 --- a/testsuite/tests/rename/should_fail/rnfail055.stderr +++ b/testsuite/tests/rename/should_fail/rnfail055.stderr @@ -93,6 +93,7 @@ RnFail055.hs-boot:28:1: error: m2 :: a -> b {-# MINIMAL m2 #-} The methods do not match: There are different numbers of methods + The MINIMAL pragmas are not compatible RnFail055.hs-boot:29:1: error: Class ‘C3’ has conflicting definitions in the module |