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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2014-07-31 15:49:14 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2014-07-31 15:49:45 +0100 |
| commit | 1ae5fa451f4f554e0d652d55f9312a585188ce13 (patch) | |
| tree | 1d0ef82924eedf6803b48b8d0ba7748f9622b227 /testsuite/tests/ghci/scripts/ghci044a.script | |
| parent | bfaa17998ed0cb8b22132d8e824b274ac5f038cc (diff) | |
| download | haskell-1ae5fa451f4f554e0d652d55f9312a585188ce13.tar.gz | |
Complete work on new OVERLAPPABLE/OVERLAPPING pragmas (Trac #9242)
* Deprecate -XOverlappingInstances
* Update test suite. Several tests even had entirely unnecessary
uses of -XOverlappingInstances
* Update user manual with a careful description of the instance
resolution story
* Fix an outright bug in the handling of duplidate instances in GHCi,
which are meant to silently overwrite the earlier duplicate. The
logic was right for family instances but was both more complicated,
and plain wrong, for class instances. (If you are interested, the
bug was that we were eliminating the duplicate from the InstEnv, but
not from the [ClsInst] held in tcg_insts.) Test is ghci044a.
Diffstat (limited to 'testsuite/tests/ghci/scripts/ghci044a.script')
| -rw-r--r-- | testsuite/tests/ghci/scripts/ghci044a.script | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/testsuite/tests/ghci/scripts/ghci044a.script b/testsuite/tests/ghci/scripts/ghci044a.script new file mode 100644 index 0000000000..d78c5c25bc --- /dev/null +++ b/testsuite/tests/ghci/scripts/ghci044a.script @@ -0,0 +1,9 @@ +--Testing flexible and Overlapping instances +class C a where { f :: a -> String; f _ = "Default" } +instance C Int where { f _ = "Zeroth" } +:set -XFlexibleInstances +instance C [Int] where f _ = "First" +f [3::Int] +-- Should override the identical one preceding +instance C [Int] where f _ = "Second" +f [3::Int] |