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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2019-03-13 11:15:20 +0000 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-03-16 08:08:25 -0400 |
| commit | 4927117cd6166a97455d788dbf7433c95441b57a (patch) | |
| tree | 07a0e4b2277d0db641254f8b4c0c2fe3f33d588f /testsuite/tests/typecheck/should_fail/tcfail212.stderr | |
| parent | 57201bebaeb15c5635ac5ea153b0141b55670199 (diff) | |
| download | haskell-4927117cd6166a97455d788dbf7433c95441b57a.tar.gz | |
Improve error recovery in the typechecker
Issue #16418 showed that we were carrying on too eagerly after a bogus
type signature was identified (a bad telescope in fact), leading to a
subsequent crash.
This led me in to a maze of twisty little passages in the typechecker's
error recovery, and I ended up doing some refactoring in TcRnMonad.
Some specfifics
* TcRnMonad.try_m is now called attemptM.
* I switched the order of the result pair in tryTc,
to make it consistent with other similar functions.
* The actual exception used in the Tc monad is irrelevant so,
to avoid polluting type signatures, I made tcTryM, a simple
wrapper around tryM, and used it.
The more important changes are in
* TcSimplify.captureTopConstraints, where we should have been calling
simplifyTop rather than reportUnsolved, so that levity defaulting
takes place properly.
* TcUnify.emitResidualTvConstraint, where we need to set the correct
status for a new implication constraint. (Previously we ended up
with an Insoluble constraint wrapped in an Unsolved implication,
which meant that insolubleWC gave the wrong answer.
Diffstat (limited to 'testsuite/tests/typecheck/should_fail/tcfail212.stderr')
| -rw-r--r-- | testsuite/tests/typecheck/should_fail/tcfail212.stderr | 22 |
1 files changed, 0 insertions, 22 deletions
diff --git a/testsuite/tests/typecheck/should_fail/tcfail212.stderr b/testsuite/tests/typecheck/should_fail/tcfail212.stderr index ad5985e63a..011a3772ef 100644 --- a/testsuite/tests/typecheck/should_fail/tcfail212.stderr +++ b/testsuite/tests/typecheck/should_fail/tcfail212.stderr @@ -16,25 +16,3 @@ tcfail212.hs:13:7: error: tcfail212.hs:13:13: error: • Expecting a lifted type, but ‘Int#’ is unlifted • In the type signature: g :: (Int#, Int#) - -tcfail212.hs:14:6: error: - • Couldn't match a lifted type with an unlifted type - When matching types - a :: * - Int# :: TYPE 'IntRep - • In the expression: 1# - In the expression: (1#, 2#) - In an equation for ‘g’: g = (1#, 2#) - • Relevant bindings include - g :: (a, b) (bound at tcfail212.hs:14:1) - -tcfail212.hs:14:10: error: - • Couldn't match a lifted type with an unlifted type - When matching types - b :: * - Int# :: TYPE 'IntRep - • In the expression: 2# - In the expression: (1#, 2#) - In an equation for ‘g’: g = (1#, 2#) - • Relevant bindings include - g :: (a, b) (bound at tcfail212.hs:14:1) |