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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2018-08-24 16:40:28 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2018-08-24 16:47:22 +0100 |
| commit | ff29fc84c03c800cfa04c2a00eb8edf6fa5f4183 (patch) | |
| tree | 16660e00d3d8f57af74384eb642a3723b45f4f4e /testsuite/tests/dependent | |
| parent | 4b79329f24dfdf907f223ff9fc41c77d9df86e04 (diff) | |
| download | haskell-ff29fc84c03c800cfa04c2a00eb8edf6fa5f4183.tar.gz | |
Better error reporting for inaccessible code
This patch fixes Trac #15558. There turned out to be
two distinct problems
* In TcExpr.tc_poly_expr_nc we had
tc_poly_expr_nc (L loc expr) res_ty
= do { traceTc "tcPolyExprNC" (ppr res_ty)
; (wrap, expr')
<- tcSkolemiseET GenSigCtxt res_ty $ \ res_ty ->
setSrcSpan loc $
-- NB: setSrcSpan *after* skolemising,
-- so we get better skolem locations
tcExpr expr res_ty
Putting the setSrcSpan inside the tcSkolemise means that
the location on the Implication constraint is the /call/
to the function rather than the /argument/ to the call,
and that is really quite wrong.
I don't know what Richard's comment NB means -- I moved the
setSrcSpan outside, and the "binding site" info in error
messages actually improved.
The reason I found this is that it affects the span reported
for Trac #15558.
* In TcErrors.mkGivenErrorReporter we carefully munge the location
for an insoluble Given constraint (Note [Inaccessible code]).
But the 'implic' passed in wasn't necesarily the immediately-
enclosing implication -- but for location-munging purposes
it jolly well should be.
Solution: use the innermost implication. This actually
simplifies the code -- no need to pass an implication in to
mkGivenErrorReporter.
Diffstat (limited to 'testsuite/tests/dependent')
| -rw-r--r-- | testsuite/tests/dependent/should_fail/T14066d.stderr | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/testsuite/tests/dependent/should_fail/T14066d.stderr b/testsuite/tests/dependent/should_fail/T14066d.stderr index 3f5eb9825a..8ece51029b 100644 --- a/testsuite/tests/dependent/should_fail/T14066d.stderr +++ b/testsuite/tests/dependent/should_fail/T14066d.stderr @@ -4,7 +4,7 @@ T14066d.hs:11:35: error: ‘b1’ is a rigid type variable bound by a type expected by the context: forall c b1 (a :: c). (Proxy a, Proxy c, b1) - at T14066d.hs:11:33-35 + at T14066d.hs:11:35 ‘b’ is a rigid type variable bound by the type signature for: f :: forall b. b -> (Proxy Maybe, ()) |