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| author | Ryan Scott <ryan.gl.scott@gmail.com> | 2020-03-05 20:57:24 -0500 |
|---|---|---|
| committer | Ryan Scott <ryan.gl.scott@gmail.com> | 2020-03-06 18:29:56 -0500 |
| commit | 38ae9c6219d2e339a2793385ca090851d0ba5d14 (patch) | |
| tree | 9b9c98537419a33dc4484708dfa112b2913c4280 /compiler/GHC | |
| parent | 067632342cf2f063b0f23c255740e2717e5e14c7 (diff) | |
| download | haskell-wip/T17899.tar.gz | |
Use InstanceSigs in GND/DerivingVia-generated code (#17899)wip/T17899
Aside from making the generated code easier to read when
`-ddump-deriv` is enabled, this makes the error message in `T15073`
substantially simpler (see the updated `T15073` expected stderr).
Fixes #17899.
Diffstat (limited to 'compiler/GHC')
| -rw-r--r-- | compiler/GHC/Hs/Utils.hs | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/compiler/GHC/Hs/Utils.hs b/compiler/GHC/Hs/Utils.hs index ac157d4caf..36e0c6d2c4 100644 --- a/compiler/GHC/Hs/Utils.hs +++ b/compiler/GHC/Hs/Utils.hs @@ -725,9 +725,10 @@ signatures in order to kind-check. Here is an example from #14579: The derived Eq instance for Glurp (without any kind signatures) would be: instance Eq a => Eq (Glurp a) where + (==) :: Glurp a -> Glurp a -> Bool (==) = coerce @(Wat2 P -> Wat2 P -> Bool) @(Glurp a -> Glurp a -> Bool) - (==) :: Glurp a -> Glurp a -> Bool + (==) (Where the visible type applications use types produced by typeToLHsType.) |