And I should say, you might try a newer ghc, they fix things all the time. Stack is still on ghc 8.0.2, but newer snapshots are on 8.2.2. On Mon, Dec 11, 2017 at 11:43 AM, David McBride wrote:

It may be a bug in ghc. It may be a bug in stack. Not much you can do about it other than to report it.

On Mon, Dec 11, 2017 at 11:39 AM, Baa wrote:

...

Hello, List. I hit error:

ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): initTc: unsolved constraints WC {wc_insol = [W] spec_a86e :: t_a86d[tau:1] (CHoleCan: spec)}

Please report this as a GHC bug: http://www.haskell.org/ghc/rep ortabug

what does it mean and how to fix it?

PS. I only added template Haskell "call" in my test suite like

$(blahBlah something)

The same call works fine in other modules and in GHCI. "stack build" works too, but tests - no (last stack 1.6.1)

=== Best regards, Paul _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

It is all detailed in the error message. http://www.haskell.org/ghc/reportabug On Mon, Dec 11, 2017 at 12:15 PM, Baa wrote:

Hello, David. Something new :) So,

1. How to report such bug? 2. How to upgrade to 8.2.2 and to new LTS? I tried to change "resolve: lts-XX" to "resolve: ghc-8.2.2" in stack.yaml but hit many errors.

...

And I should say, you might try a newer ghc, they fix things all the time. Stack is still on ghc 8.0.2, but newer snapshots are on 8.2.2.

On Mon, Dec 11, 2017 at 11:43 AM, David McBride wrote:

...

It may be a bug in ghc. It may be a bug in stack. Not much you can do about it other than to report it.

On Mon, Dec 11, 2017 at 11:39 AM, Baa wrote:

...

Hello, List. I hit error:

ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): initTc: unsolved constraints WC {wc_insol = [W] spec_a86e :: t_a86d[tau:1] (CHoleCan: spec)}

Please report this as a GHC bug: http://www.haskell.org/ghc/rep ortabug

what does it mean and how to fix it?

PS. I only added template Haskell "call" in my test suite like

$(blahBlah something)

The same call works fine in other modules and in GHCI. "stack build" works too, but tests - no (last stack 1.6.1)

=== Best regards, Paul _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners