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| author | Thomas Miedema <thomasmiedema@gmail.com> | 2016-06-18 22:44:19 +0200 |
|---|---|---|
| committer | Thomas Miedema <thomasmiedema@gmail.com> | 2016-06-20 16:22:07 +0200 |
| commit | 3dc1202546e63b50f828a34474717b1ddcbed5c7 (patch) | |
| tree | 745fde8e9712c6d0b0507d9ae4988736c678abdb /testsuite/tests/typecheck/should_fail/tcfail138.hs | |
| parent | cf6e65693588cd9d40c895279f2e53d3d25a2c58 (diff) | |
| download | haskell-3dc1202546e63b50f828a34474717b1ddcbed5c7.tar.gz | |
Testsuite: tabs -> spaces [skip ci]
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/tcfail138.hs')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/tcfail138.hs | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/testsuite/tests/typecheck/should_fail/tcfail138.hs b/testsuite/tests/typecheck/should_fail/tcfail138.hs index 63485a32df..31cde734ec 100644 --- a/testsuite/tests/typecheck/should_fail/tcfail138.hs +++ b/testsuite/tests/typecheck/should_fail/tcfail138.hs @@ -12,16 +12,16 @@ -- In the instance declaration for `C (Maybe a) a' -- -- Since L is a superclass of the (sought) constraint (C a b'), you might --- think that we'd generate the superclasses (L a b') and (L a b), and now +-- think that we'd generate the superclasses (L a b') and (L a b), and now -- the fundep will force b=b'. But GHC is very cautious about generating -- superclasses when doing context reduction for instance declarations, -- because of the danger of superclass loops. -- -- So, today, this program fails. It's trivial to fix by adding a fundep for C --- class (G a, L a b) => C a b | a -> b +-- class (G a, L a b) => C a b | a -> b --- Note: Sept 08: when fixing Trac #1470, tc138 started working! --- This test is a very strange one (fundeps, undecidable instances), +-- Note: Sept 08: when fixing Trac #1470, tc138 started working! +-- This test is a very strange one (fundeps, undecidable instances), -- so I'm just marking it as "should-succeed". It's not very clear to -- me what the "right" answer should be; when we have the type equality -- story more worked out we might want to think about that. |