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| author | David Kraeutmann <kane@kane.cx> | 2015-10-07 20:28:46 -0500 |
|---|---|---|
| committer | Austin Seipp <austin@well-typed.com> | 2015-10-07 20:30:20 -0500 |
| commit | 7b443bb1df8f7f0a6b3124537590aa655a9300cd (patch) | |
| tree | 9a15aeb8de755743b236f83129ad63fa4ec93304 /testsuite/tests/quotes | |
| parent | ea4df12f7f3fc4d1d2af335804b8ec893f45550c (diff) | |
| download | haskell-7b443bb1df8f7f0a6b3124537590aa655a9300cd.tar.gz | |
Improve error messages for ambiguous type variables
Improved error messages are only printed when the old message would be
"No instance for...", since they're not as helpful for "Could not deduce..."
No special test case as error messages are tested by other tests already.
Signed-off-by: David Kraeutmann <kane@kane.cx>
Reviewed By: austin, goldfire
Differential Revision: https://phabricator.haskell.org/D1182
GHC Trac Issues: #10733
Diffstat (limited to 'testsuite/tests/quotes')
| -rw-r--r-- | testsuite/tests/quotes/TH_localname.stderr | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/testsuite/tests/quotes/TH_localname.stderr b/testsuite/tests/quotes/TH_localname.stderr index c764f576ef..dfb1e41383 100644 --- a/testsuite/tests/quotes/TH_localname.stderr +++ b/testsuite/tests/quotes/TH_localname.stderr @@ -1,11 +1,12 @@ TH_localname.hs:3:11: error: - No instance for (Lift t0) arising from a use of ‘lift’ - The type variable ‘t0’ is ambiguous + Ambiguous type variable ‘t0’ arising from a use of ‘lift’ + prevents the constraint ‘(Lift t0)’ from being solved. Relevant bindings include y :: t0 (bound at TH_localname.hs:3:6) x :: t0 -> ExpQ (bound at TH_localname.hs:3:1) - Potential instances: + Probable fix: use a type annotation to specify what ‘t0’ should be. + These potential instances exist: instance (Lift a, Lift b) => Lift (Either a b) -- Defined in ‘Language.Haskell.TH.Syntax’ instance Lift Int16 -- Defined in ‘Language.Haskell.TH.Syntax’ |