diff options
| author | Simon Peyton Jones <simonpj@microsoft.com> | 2012-07-21 19:10:48 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2012-07-21 19:10:48 +0100 |
| commit | afa3965dbbd76a75ee2161e9da21bcce6afa935a (patch) | |
| tree | ac23938806ca14cd8c0a16e0f90d75004ca89685 /testsuite/tests/programs/joao-circular | |
| parent | 7cf9432ad3923851e0222767432e3398f01199df (diff) | |
| download | haskell-afa3965dbbd76a75ee2161e9da21bcce6afa935a.tar.gz | |
Add a type signature for a function with an ambiguous type
There's a comment with visit_PPSArgs to explain. GHC was rightfully
rejecting visit_PPS as having an ambiguous type. And it does! It
worked before because the ambiguity involved only standard classes
and hence was resolved.
(I suppose this could be a warning instead. But I'm fixing the test
anyway.)
Diffstat (limited to 'testsuite/tests/programs/joao-circular')
| -rw-r--r-- | testsuite/tests/programs/joao-circular/Visfun_Lazy.hs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/testsuite/tests/programs/joao-circular/Visfun_Lazy.hs b/testsuite/tests/programs/joao-circular/Visfun_Lazy.hs index fa768999c0..494604eb1d 100644 --- a/testsuite/tests/programs/joao-circular/Visfun_Lazy.hs +++ b/testsuite/tests/programs/joao-circular/Visfun_Lazy.hs @@ -854,6 +854,20 @@ visit_PPCArgs (C_NilPPCArgs_1 ) x_ifillerrs x_ifillfmts x_ifillmins x_ireqs = (x x_fmts = ([] ) x_fillmins = ([] ) x_error = ([] ) + + +visit_PPSArgs :: PPSArgs -> [T_Frame] -> (T_Errs, T_Fmts, Integer, T_Mins) +-- This function's most general type is +-- visit_PPSArgs :: forall a. (Integral a, Show a) +-- => PPSArgs -> [T_Frame] -> (T_Errs, T_Fmts, a, T_Mins) +-- But in the same mutually recusive group is visit_PPS whose type becomes +-- visit_PPS :: forall a. (Integral a, Show a) +-- => PPS -> T_Frame -> (Bool, T_Formats, INT, INT, INT) +-- which GHC now (rightfully) rejects that as ambiguous, even though +-- acutally default resolution will allow it at call sites, +-- So I've added a type signature +-- SLPJ July 2012 + visit_PPSArgs (C_ConsArgs_1 t_PPS t_PPSArgs_2 ) x_reqs = (x_error , x_fmts , x_len , x_mins ) where x_reqs_2 = (tail_T_Reqs x_reqs) |