Opened 5 years ago

Closed 5 years ago

#10028 closed bug (fixed)

GHC Panic (The Impossible Happened)

Reported by: archaephyrryx Owned by:
Priority: normal Milestone:
Component: Compiler Version: 7.4.1
Keywords: panic, impossible, irrefutable Cc:
Operating System: Unknown/Multiple Architecture: x86_64 (amd64)
Type of failure: Compile-time crash Test Case:
Blocked By: Blocking:
Related Tickets: Differential Rev(s):
Wiki Page:

Description

Error message:

ghc: panic! (the 'impossible' happened)
  (GHC version 7.4.1 for x86_64-unknown-linux):
	compiler/rename/RnPat.lhs:535:39-79: Irrefutable pattern failed for pattern gres@(gre : _)

Cause:

Importing a Module containing a record-syntax defined datatype, hiding one of the record fields, causes the use of the language pragma RecordWildCards to make GHC encounter a fatal error. A minimal reproduction case is attached to this ticket.

Attachments (2)

Bar.hs (109 bytes) - added by archaephyrryx 5 years ago.
Foo.hs (56 bytes) - added by archaephyrryx 5 years ago.

Download all attachments as: .zip

Change History (3)

Changed 5 years ago by archaephyrryx

Attachment: Bar.hs added

Changed 5 years ago by archaephyrryx

Attachment: Foo.hs added

comment:1 Changed 5 years ago by simonpj

Resolution: fixed
Status: newclosed

Thanks for reporting. Happily it was fixed in 7.6, and works in 7.8 and HEAD too. So I'll close it as fixed. (We aren't going to make another release of 7.4)

Simon

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