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| author | John Wiegley <johnw@newartisans.com> | 2015-07-30 15:08:28 +0200 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2015-07-30 17:05:35 +0200 |
| commit | 4f80ec0ee438800d95673a4898e69371957fed09 (patch) | |
| tree | 47b00b465f2e700aed1e50333c8e0f74e3a754e1 /testsuite/tests/deriving/should_fail/T9600.stderr | |
| parent | 26315ed282db2eb1977872bbcb0b298f32b38e99 (diff) | |
| download | haskell-4f80ec0ee438800d95673a4898e69371957fed09.tar.gz | |
Improve error message for newtypes and deriving clauses
Summary:
Change the error message generated when a deriving clause related to a newtype
fails to always suggested trying GeneralizedNewtypeDeriving, even in
situations where it may not work. Fixes #9600.
Test Plan: testsuite/deriving/should_fail/9600.hs
Reviewers: austin, bgamari, simonpj
Rebased-by: bgamari
Reviewed By: simonpj
Subscribers: bgamari, hvr, simonmar, carter
Differential Revision: https://phabricator.haskell.org/D216
GHC Trac Issues: #9600
Diffstat (limited to 'testsuite/tests/deriving/should_fail/T9600.stderr')
| -rw-r--r-- | testsuite/tests/deriving/should_fail/T9600.stderr | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/testsuite/tests/deriving/should_fail/T9600.stderr b/testsuite/tests/deriving/should_fail/T9600.stderr new file mode 100644 index 0000000000..2e88277f54 --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T9600.stderr @@ -0,0 +1,6 @@ + +T9600.hs:3:39: error: + Can't make a derived instance of ‘Applicative Foo’: + ‘Applicative’ is not a standard derivable class (Eq, Show, etc.) + Try GeneralizedNewtypeDeriving for GHC's newtype-deriving extension + In the newtype declaration for ‘Foo’ |