Opened 3 years ago

Closed 3 years ago

Last modified 3 years ago

#10306 closed bug (fixed)

Calling reify on Any or built-in type families causes panic

Reported by: adamgundry Owned by: adamgundry
Priority: normal Milestone: 8.0.1
Component: Compiler Version: 7.10.1
Keywords: Cc:…
Operating System: Unknown/Multiple Architecture: Unknown/Multiple
Type of failure: Compile-time crash Test Case: th/T10306
Blocked By: Blocking:
Related Tickets: #9840 Differential Rev(s): Phab:D841
Wiki Page:


Both reify ''Any and reify ''(+) (where (+) is the built-in operation on type-level naturals) result in a panic TcSplice.reifyFamFlavour: not a type family. I came across this while working on #9840 and have a fix as part of Phab:D841.

Change History (4)

comment:1 Changed 3 years ago by RyanGlScott

Cc:… added

comment:2 Changed 3 years ago by Adam Gundry <adam@…>

In 4efa421327cf127ebefde59b2eece693e37dc3c6/ghc:

Permit empty closed type families

Fixes #9840 and #10306, and includes an alternative resolution to #8028.
This permits empty closed type families, and documents them in the user
guide. It updates the Haddock submodule to support the API change.

Test Plan: Added `indexed-types/should_compile/T9840` and updated
`indexed-types/should_fail/ClosedFam4` and `th/T8028`.

Reviewers: austin, simonpj, goldfire

Reviewed By: goldfire

Subscribers: bgamari, jstolarek, thomie, goldfire

Differential Revision:

GHC Trac Issues: #9840, #10306

comment:3 Changed 3 years ago by adamgundry

Resolution: fixed
Status: newclosed
Test Case: th/T10306

comment:4 Changed 3 years ago by thomie

Milestone: 8.0.1
Note: See TracTickets for help on using tickets.