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| author | Ryan Scott <ryan.gl.scott@gmail.com> | 2017-11-02 11:52:50 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2017-11-02 11:56:26 -0400 |
| commit | 1317ba625d40fbd51cb0538b3fde28f412f30c01 (patch) | |
| tree | 6f891bba014ae2fc3e9a94c6ecdfabb021a0bbf2 /testsuite/tests/deriving/should_fail | |
| parent | 29ae83374647e227d76acd896b89590fc15590d6 (diff) | |
| download | haskell-1317ba625d40fbd51cb0538b3fde28f412f30c01.tar.gz | |
Implement the EmptyDataDeriving proposal
This implements the `EmptyDataDeriving` proposal put forth in
https://github.com/ghc-proposals/ghc-proposals/blob/dbf51608/proposals/0006-deriving-empty.rst.
This has two major changes:
* The introduction of an `EmptyDataDeriving` extension, which
permits directly deriving `Eq`, `Ord`, `Read`, and `Show` instances
for empty data types.
* An overhaul in the code that is emitted in derived instances for
empty data types. To see an overview of the changes brought forth,
refer to the changes to the 8.4.1 release notes.
Test Plan: ./validate
Reviewers: bgamari, dfeuer, austin, hvr, goldfire
Reviewed By: bgamari
Subscribers: rwbarton, thomie
GHC Trac Issues: #7401, #10577, #13117
Differential Revision: https://phabricator.haskell.org/D4047
Diffstat (limited to 'testsuite/tests/deriving/should_fail')
| -rw-r--r-- | testsuite/tests/deriving/should_fail/T7401_fail.hs | 3 | ||||
| -rw-r--r-- | testsuite/tests/deriving/should_fail/T7401_fail.stderr | 6 | ||||
| -rw-r--r-- | testsuite/tests/deriving/should_fail/all.T | 1 |
3 files changed, 10 insertions, 0 deletions
diff --git a/testsuite/tests/deriving/should_fail/T7401_fail.hs b/testsuite/tests/deriving/should_fail/T7401_fail.hs new file mode 100644 index 0000000000..730223f179 --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T7401_fail.hs @@ -0,0 +1,3 @@ +module T7401_fail where + +data D deriving Eq diff --git a/testsuite/tests/deriving/should_fail/T7401_fail.stderr b/testsuite/tests/deriving/should_fail/T7401_fail.stderr new file mode 100644 index 0000000000..feb841f962 --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T7401_fail.stderr @@ -0,0 +1,6 @@ + +T7401_fail.hs:3:17: error: + • Can't make a derived instance of ‘Eq D’: + ‘D’ must have at least one data constructor + Use EmptyDataDeriving to enable deriving for empty data types + • In the data declaration for ‘D’ diff --git a/testsuite/tests/deriving/should_fail/all.T b/testsuite/tests/deriving/should_fail/all.T index 1861e6dd0a..c9b8469c3c 100644 --- a/testsuite/tests/deriving/should_fail/all.T +++ b/testsuite/tests/deriving/should_fail/all.T @@ -44,6 +44,7 @@ test('T7148a', normal, compile_fail, ['']) # T7800 was removed as it was out of date re: fixing #9858 test('T5498', normal, compile_fail, ['']) test('T6147', normal, compile_fail, ['']) +test('T7401_fail', normal, compile_fail, ['']) test('T8165_fail1', normal, compile_fail, ['']) test('T8165_fail2', normal, compile_fail, ['']) test('T8851', normal, compile_fail, ['']) |