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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2016-02-04 13:00:22 +0000 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2016-02-08 15:08:40 +0000 |
| commit | a96c4e7ca391ff3003d5debf187e7d177131f2fe (patch) | |
| tree | fb733d6a93f9fa83c3e87ad7d5af429c881f0ff3 /testsuite/tests | |
| parent | 6036cb6f67892e445bb3150850365dc7c7d64a40 (diff) | |
| download | haskell-a96c4e7ca391ff3003d5debf187e7d177131f2fe.tar.gz | |
Add comments to TcCoercibleFail
Flag up the problem highlighted in Trac #11518 comment:15
Diffstat (limited to 'testsuite/tests')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs | 7 | ||||
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr | 6 |
2 files changed, 10 insertions, 3 deletions
diff --git a/testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs b/testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs index c102da5cf8..833609d48a 100644 --- a/testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs +++ b/testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs @@ -20,9 +20,16 @@ foo4 = coerce $ one :: Down Int newtype Void = Void Void foo5 = coerce :: Void -> () + +------------------------------------ +-- This next one generates an exponentally big type as it +-- tries to unwrap. See comment:15 in Trac #11518 +-- Adding asserions that force the types can make us +-- run out of space. newtype VoidBad a = VoidBad (VoidBad (a,a)) foo5' = coerce :: (VoidBad ()) -> () +------------------------------------ -- This shoul fail with a context stack overflow newtype Fix f = Fix (f (Fix f)) foo6 = coerce :: Fix (Either Int) -> Fix (Either Age) diff --git a/testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr b/testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr index 32dac6a133..8c0df32063 100644 --- a/testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr +++ b/testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr @@ -37,14 +37,14 @@ TcCoercibleFail.hs:21:8: error: • In the expression: coerce :: Void -> () In an equation for ‘foo5’: foo5 = coerce :: Void -> () -TcCoercibleFail.hs:24:9: error: +TcCoercibleFail.hs:30:9: error: • Couldn't match representation of type ‘VoidBad ()’ with that of ‘()’ arising from a use of ‘coerce’ • In the expression: coerce :: (VoidBad ()) -> () In an equation for ‘foo5'’: foo5' = coerce :: (VoidBad ()) -> () -TcCoercibleFail.hs:28:8: error: +TcCoercibleFail.hs:35:8: error: • Reduction stack overflow; size = 201 When simplifying the following type: Coercible (Fix (Either Int)) (Fix (Either Age)) @@ -56,7 +56,7 @@ TcCoercibleFail.hs:28:8: error: In an equation for ‘foo6’: foo6 = coerce :: Fix (Either Int) -> Fix (Either Age) -TcCoercibleFail.hs:29:8: error: +TcCoercibleFail.hs:36:8: error: • Couldn't match representation of type ‘Either Int (Fix (Either Int))’ with that of ‘()’ |