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| 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/patsyn | |
| 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/patsyn')
| -rw-r--r-- | testsuite/tests/patsyn/should_fail/T15289.stderr | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/testsuite/tests/patsyn/should_fail/T15289.stderr b/testsuite/tests/patsyn/should_fail/T15289.stderr index 952d358692..64cc153ff8 100644 --- a/testsuite/tests/patsyn/should_fail/T15289.stderr +++ b/testsuite/tests/patsyn/should_fail/T15289.stderr @@ -1,10 +1,4 @@ -T15289.hs:5:16: error: - • Couldn't match expected type ‘Maybe’ with actual type ‘Bool’ - • In the pattern: True - In the pattern: True :: Maybe - In the declaration for pattern synonym ‘What’ - T15289.hs:5:24: error: • Expecting one more argument to ‘Maybe’ Expected a type, but ‘Maybe’ has kind ‘* -> *’ |