[commit: ghc] ghc-8.2: Fix ASSERT failure in TcErrors (95ca115)
git at git.haskell.org
git at git.haskell.org
Thu Mar 30 00:38:08 UTC 2017
Repository : ssh://git@git.haskell.org/ghc
On branch : ghc-8.2
Link : http://ghc.haskell.org/trac/ghc/changeset/95ca115d22ce3dc7f9ad53d8d8a74175121fdda8/ghc
>---------------------------------------------------------------
commit 95ca115d22ce3dc7f9ad53d8d8a74175121fdda8
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date: Wed Mar 29 14:57:21 2017 +0100
Fix ASSERT failure in TcErrors
This fixes Trac #13494, by improving
commit e0ad55f894a8d85dcc099c33c63cfe3d4515d464
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date: Mon Mar 27 10:32:08 2017 +0100
Fix error-message suppress on given equalities
which in turn was a fix to #13446
(cherry picked from commit f88ac374c5cb150d4f172fb40be338d2112a0600)
>---------------------------------------------------------------
95ca115d22ce3dc7f9ad53d8d8a74175121fdda8
compiler/typecheck/TcErrors.hs | 29 ++++++++++++----------
.../tests/indexed-types/should_fail/T2627b.stderr | 10 +++-----
.../tests/indexed-types/should_fail/T6123.stderr | 3 ++-
.../tests/indexed-types/should_fail/T7354.stderr | 5 ++--
4 files changed, 23 insertions(+), 24 deletions(-)
diff --git a/compiler/typecheck/TcErrors.hs b/compiler/typecheck/TcErrors.hs
index 84a28a7..9701637 100644
--- a/compiler/typecheck/TcErrors.hs
+++ b/compiler/typecheck/TcErrors.hs
@@ -1474,22 +1474,21 @@ mkTyVarEqErr dflags ctxt report ct oriented tv1 ty2
, report
]
- -- So tv is a meta tyvar (or started that way before we
- -- generalised it). So presumably it is an *untouchable*
- -- meta tyvar or a SigTv, else it'd have been unified
| OC_Occurs <- occ_check_expand
- , insoluble_occurs_check
- -- See Note [Occurs check error] in TcCanonical
- = do { let occCheckMsg = important $ addArising (ctOrigin ct) $
- hang (text "Occurs check: cannot construct the infinite" <+> what <> colon)
+ -- We report an "occurs check" even for a ~ F t a, where F is a type
+ -- function; it's not insouble (because in principle F could reduce)
+ -- but we have certainly been unable to solve it
+ -- See Note [Occurs check error] in TcCanonical
+ = do { let main_msg = addArising (ctOrigin ct) $
+ hang (text "Occurs check: cannot construct the infinite" <+> what <> colon)
2 (sep [ppr ty1, char '~', ppr ty2])
+
extra2 = important $ mkEqInfoMsg ct ty1 ty2
- interesting_tyvars
- = filter (not . noFreeVarsOfType . tyVarKind) $
- filter isTyVar $
- fvVarList $
- tyCoFVsOfType ty1 `unionFV` tyCoFVsOfType ty2
+ interesting_tyvars = filter (not . noFreeVarsOfType . tyVarKind) $
+ filter isTyVar $
+ fvVarList $
+ tyCoFVsOfType ty1 `unionFV` tyCoFVsOfType ty2
extra3 = relevant_bindings $
ppWhen (not (null interesting_tyvars)) $
hang (text "Type variable kinds:") 2 $
@@ -1497,7 +1496,8 @@ mkTyVarEqErr dflags ctxt report ct oriented tv1 ty2
interesting_tyvars)
tyvar_binding tv = ppr tv <+> dcolon <+> ppr (tyVarKind tv)
- ; mkErrorMsgFromCt ctxt ct $ mconcat [occCheckMsg, extra2, extra3, report] }
+ ; mkErrorMsgFromCt ctxt ct $
+ mconcat [important main_msg, extra2, extra3, report] }
| OC_Bad <- occ_check_expand
= do { let msg = vcat [ text "Cannot instantiate unification variable"
@@ -1546,6 +1546,9 @@ mkTyVarEqErr dflags ctxt report ct oriented tv1 ty2
; mkErrorMsgFromCt ctxt ct (mconcat [msg, tv_extra, report]) }
-- Nastiest case: attempt to unify an untouchable variable
+ -- So tv is a meta tyvar (or started that way before we
+ -- generalised it). So presumably it is an *untouchable*
+ -- meta tyvar or a SigTv, else it'd have been unified
-- See Note [Error messages for untouchables]
| (implic:_) <- cec_encl ctxt -- Get the innermost context
, Implic { ic_env = env, ic_given = given
diff --git a/testsuite/tests/indexed-types/should_fail/T2627b.stderr b/testsuite/tests/indexed-types/should_fail/T2627b.stderr
index 1a09bd8..63f11b9 100644
--- a/testsuite/tests/indexed-types/should_fail/T2627b.stderr
+++ b/testsuite/tests/indexed-types/should_fail/T2627b.stderr
@@ -1,13 +1,9 @@
T2627b.hs:20:24: error:
- • Couldn't match type ‘b0’ with ‘Dual (Dual b0)’
+ • Occurs check: cannot construct the infinite type:
+ b0 ~ Dual (Dual b0)
arising from a use of ‘conn’
- ‘b0’ is untouchable
- inside the constraints: b ~ W e f
- bound by a pattern with constructor:
- Wr :: forall e f. e -> Comm f -> Comm (W e f),
- in an equation for ‘conn’
- at T2627b.hs:20:14-19
+ The type variable ‘b0’ is ambiguous
• In the expression: conn undefined undefined
In an equation for ‘conn’:
conn (Rd k) (Wr a r) = conn undefined undefined
diff --git a/testsuite/tests/indexed-types/should_fail/T6123.stderr b/testsuite/tests/indexed-types/should_fail/T6123.stderr
index eafd27c..0ae1a5e 100644
--- a/testsuite/tests/indexed-types/should_fail/T6123.stderr
+++ b/testsuite/tests/indexed-types/should_fail/T6123.stderr
@@ -1,6 +1,7 @@
T6123.hs:10:14: error:
- • Couldn't match type ‘a0’ with ‘Id a0’ arising from a use of ‘cid’
+ • Occurs check: cannot construct the infinite type: a0 ~ Id a0
+ arising from a use of ‘cid’
The type variable ‘a0’ is ambiguous
• In the expression: cid undefined
In an equation for ‘cundefined’: cundefined = cid undefined
diff --git a/testsuite/tests/indexed-types/should_fail/T7354.stderr b/testsuite/tests/indexed-types/should_fail/T7354.stderr
index f4c3c0d..b7b70b8 100644
--- a/testsuite/tests/indexed-types/should_fail/T7354.stderr
+++ b/testsuite/tests/indexed-types/should_fail/T7354.stderr
@@ -1,8 +1,7 @@
T7354.hs:28:11: error:
- • Couldn't match type ‘p’ with ‘Base t (Prim [p] p)’
- ‘p’ is a rigid type variable bound by
- the inferred type of foo :: Prim [p] p -> t at T7354.hs:28:1-13
+ • Occurs check: cannot construct the infinite type:
+ p ~ Base t (Prim [p] p)
Expected type: Prim [p] p -> Base t (Prim [p] p)
Actual type: Prim [p] p -> p
• In the first argument of ‘ana’, namely ‘alg’
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