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| author | Ryan Scott <ryan.gl.scott@gmail.com> | 2017-10-19 10:21:17 -0400 |
|---|---|---|
| committer | Ryan Scott <ryan.gl.scott@gmail.com> | 2017-10-19 10:21:17 -0400 |
| commit | 101a8c770b9d3abd57ff289bffea3d838cf25c80 (patch) | |
| tree | 06a8a10674970562d4d07555f3c51653c5270662 /testsuite | |
| parent | e023e78bc13ffae168f00a52324fc406a146b40f (diff) | |
| download | haskell-101a8c770b9d3abd57ff289bffea3d838cf25c80.tar.gz | |
Error when deriving instances in hs-boot files
Summary:
According to the GHC users' guide, one cannot derive
instances for data types in `.hs-boot` files.
However, GHC was not enforcing this in practice, which led to
#14365.
Fix this by actually throwing an error if a derived instance is
detected in an `.hs-boot` file (and recommend how to fix it in the
error message.)
Test Plan: make test TEST=T14365
Reviewers: ezyang, austin, bgamari, simonpj
Reviewed By: simonpj
Subscribers: simonpj, rwbarton, thomie
GHC Trac Issues: #14365
Differential Revision: https://phabricator.haskell.org/D4102
Diffstat (limited to 'testsuite')
6 files changed, 35 insertions, 2 deletions
diff --git a/testsuite/tests/deriving/should_fail/T14365.stderr b/testsuite/tests/deriving/should_fail/T14365.stderr new file mode 100644 index 0000000000..f8f106fea8 --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T14365.stderr @@ -0,0 +1,13 @@ +[1 of 3] Compiling T14365B[boot] ( T14365B.hs-boot, T14365B.o-boot ) + +T14365B.hs-boot:5:13: error: + • Can't make a derived instance of ‘Functor Foo’: + Cannot derive instances in hs-boot files + Write an instance declaration instead + • In the data declaration for ‘Foo’ + +T14365B.hs-boot:7:1: error: + • Can't make a derived instance of ‘Foldable Foo’: + Cannot derive instances in hs-boot files + Write an instance declaration instead + • In the stand-alone deriving instance for ‘Foldable Foo’ diff --git a/testsuite/tests/deriving/should_fail/T14365A.hs b/testsuite/tests/deriving/should_fail/T14365A.hs new file mode 100644 index 0000000000..e80e7d108a --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T14365A.hs @@ -0,0 +1,5 @@ +module T14365A where + +import {-# SOURCE #-} T14365B + +main = return () diff --git a/testsuite/tests/deriving/should_fail/T14365B.hs b/testsuite/tests/deriving/should_fail/T14365B.hs new file mode 100644 index 0000000000..596c275410 --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T14365B.hs @@ -0,0 +1,4 @@ +module T14365B where + +data Foo a = Foo a + deriving (Functor) diff --git a/testsuite/tests/deriving/should_fail/T14365B.hs-boot b/testsuite/tests/deriving/should_fail/T14365B.hs-boot new file mode 100644 index 0000000000..1dcbc9494c --- /dev/null +++ b/testsuite/tests/deriving/should_fail/T14365B.hs-boot @@ -0,0 +1,7 @@ +{-# LANGUAGE StandaloneDeriving #-} +module T14365B where + +data Foo a + deriving (Functor) + +deriving instance Foldable Foo diff --git a/testsuite/tests/deriving/should_fail/all.T b/testsuite/tests/deriving/should_fail/all.T index 77ce1454cb..1861e6dd0a 100644 --- a/testsuite/tests/deriving/should_fail/all.T +++ b/testsuite/tests/deriving/should_fail/all.T @@ -66,3 +66,5 @@ test('T11509_1', [when(doing_ghci(), extra_hc_opts('-fobject-code'))], test('T12163', normal, compile_fail, ['']) test('T12512', omit_ways(['ghci']), compile_fail, ['']) test('T12801', normal, compile_fail, ['']) +test('T14365', [extra_files(['T14365B.hs','T14365B.hs-boot'])], + multimod_compile_fail, ['T14365A','']) diff --git a/testsuite/tests/deriving/should_fail/drvfail016.stderr b/testsuite/tests/deriving/should_fail/drvfail016.stderr index 182b74893f..05abbf5bb9 100644 --- a/testsuite/tests/deriving/should_fail/drvfail016.stderr +++ b/testsuite/tests/deriving/should_fail/drvfail016.stderr @@ -1,4 +1,6 @@ drvfail016.hs-boot:7:14: error: - Deriving not permitted in hs-boot file - Use an instance declaration instead + • Can't make a derived instance of ‘Show D’: + Cannot derive instances in hs-boot files + Write an instance declaration instead + • In the data declaration for ‘D’ |