diff options
| author | Simon Peyton Jones <simonpj@microsoft.com> | 2019-02-14 08:28:43 +0000 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2019-02-14 08:40:03 +0000 |
| commit | 5c1f268e2744fab2d36e64c163858995451d7095 (patch) | |
| tree | cb9b05c9112e6df43d90f28b6e3a252b2a077d46 /testsuite/tests/typecheck/should_fail/T13819.stderr | |
| parent | 682783828275cca5fd8bf5be5b52054c75e0e22c (diff) | |
| download | haskell-5c1f268e2744fab2d36e64c163858995451d7095.tar.gz | |
Fail fast in solveLocalEqualities
This patch makes us fail fast in TcSimplify.solveLocalEqualities,
and in TcHsType.tc_hs_sig_type, if there are insoluble constraints.
Previously we ploughed on even if there were insoluble constraints,
leading to a cascade of hard-to-understand type errors. Failing
eagerly is much better; hence a lot of testsuite error message
changes. Eg if we have
f :: [Maybe] -> blah
f xs = e
then trying typecheck 'f x = e' with an utterly bogus type
is just asking for trouble.
I can't quite remember what provoked me to make this change,
but I think the error messages are notably improved, by
removing confusing clutter and focusing on the real error.
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/T13819.stderr')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/T13819.stderr | 11 |
1 files changed, 0 insertions, 11 deletions
diff --git a/testsuite/tests/typecheck/should_fail/T13819.stderr b/testsuite/tests/typecheck/should_fail/T13819.stderr index 89959cba39..917345f710 100644 --- a/testsuite/tests/typecheck/should_fail/T13819.stderr +++ b/testsuite/tests/typecheck/should_fail/T13819.stderr @@ -1,15 +1,4 @@ -T13819.hs:12:10: error: - • Couldn't match type ‘_0 -> A _0’ with ‘A a’ - Expected type: a -> A a - Actual type: (_1 -> WrappedMonad A _2) (_0 -> A _0) - • In the expression: pure @(_ -> WrappedMonad A _) @(_ -> A _) pure - In an equation for ‘pure’: - pure = pure @(_ -> WrappedMonad A _) @(_ -> A _) pure - In the instance declaration for ‘Applicative A’ - • Relevant bindings include - pure :: a -> A a (bound at T13819.hs:12:3) - T13819.hs:12:17: error: • Expected kind ‘* -> *’, but ‘_ -> WrappedMonad A _’ has kind ‘*’ • In the type ‘(_ -> WrappedMonad A _)’ |