Re: [Haskell-beginners] How to install new GHC ?

That's right, the template-haskell API frequently changes between major releases of GHC. On Tue, Dec 12, 2017, 4:35 PM Baa wrote:

@Michael Snoyman:

I returned back all .cabal-files and added compiler: ghc-8.2.2, `stack build` printed out this:

---cut--- Error: While constructing the build plan, the following exceptions were encountered:

In the dependencies for Cabal-1.24.2.0: process-1.6.1.0 from stack configuration does not match >=1.1.0.1 && <1.5 (latest matching version is 1.4.3.0) needed due to my-common-utils-0.2.0.0 -> Cabal-1.24.2.0

In the dependencies for versions-3.1.1: base-4.10.1.0 from stack configuration does not match >=4.8 && <4.10 (latest matching version is 4.9.1.0) needed due to my-common-utils-0.2.0.0 -> versions-3.1.1

Some potential ways to resolve this:

* Recommended action: try adding the following to your extra-deps in /home/pavel/prj/automation/revcompl-mon/stack.yaml:

- base-4.9.1.0 - process-1.4.3.0

* Set 'allow-newer: true' to ignore all version constraints and build anyway.

* You may also want to try using the 'stack solver' command.

Plan construction failed. ---cut---

After adding "allow-newer: true" build process starts, all looked fine until:

.../SimpleTagging.hs:281:51: error: • Couldn't match type ‘Type’ with ‘DerivClause’ Expected type: [DerivClause] Actual type: [Type] • In the sixth argument of ‘DataD’, namely ‘derivs'’ In the expression: DataD [] ty' tyVars Nothing newCs derivs' In the first argument of ‘(++)’, namely ‘[DataD [] ty' tyVars Nothing newCs derivs']’ | 281 | return $ [DataD [] ty' tyVars Nothing newCs derivs'] ++ showInst | ^^^^^^^

which IMHO means that TemplateHaskell ("API") was changed from 8.0.2 to 8.2.2 because the same code is compiling with old GHC 8.0.2.

...

Hi Paul,

A Stackage snapshot specifies both a GHC version and a set of packages. Stackage snapshots are built and tested to ensure that the packages are compatible. While you could tell Stack to use a different GHC version with a snapshot[1], this is unlikely to work, since GHC major releases usually break some packages.

I think everyone who's trying to help you (both with Cabal and Stack workflows) would be able to do so better if you explain which package you're trying to use which is no longer available in Stackage Nightly. In some cases, you can simply add it as an extra dependencies for Stack (e.g., `extra-deps: [acme-missiles-0.3]`), while in others there is some inherent incompatibility.

Right now, you'll just be getting guesses about how to theoretically get some unknown package to build with a bunch of others.

Michael

[1] Using a setting like `compiler: ghc-8.2.2`

On Tue, Dec 12, 2017 at 3:43 PM, Baa wrote:

...

@David: I tried to switch to nightly but in project's .yaml file and got error about missing of some library (as I understand, it is missing in last nightly). So, if I try to do it through .yaml file then how to use new GHC (8.2.2) but with LTS for 8.0.2? Is it possible? I need last stable LTS where all libraries (using in the projects) exist, but with new GHC 8.2.2 which is too new for stable LTS. As I read somewhere, GHC version and Stackage version are linked together hardly in stack tool, or?

...

You can see how to configure stack here: https://github.com/commercialhaskell/stack/blob/release/doc/yaml_ configuration.md

The short of it is that to have stack ghci choose a particular version of ghc, you probably need to modify ~/.stack/global/stack.yaml, change resolver to something here https://www.stackage.org/snapshots that has your version of ghc and dependencies similar to what your project wants. For example 'nightly-2017-12-10'.

On Tue, Dec 12, 2017 at 7:53 AM, Baa wrote:

...

@Francesco: unfortunately nightly misses some package. So, I tried:

$ stack --resolver=ghc-8.2.2 setup --reinstall Preparing to install GHC (tinfo6) to an isolated location. This will not interfere with any system-level installation. Already downloaded. Installed GHC.

stack will use a sandboxed GHC it installed For more information on paths, see 'stack path' and 'stack exec env' To use this GHC and packages outside of a project, consider using: stack ghc, stack ghci, stack runghc, or stack exec

So seems that 8.2.2 was installed, right? But how to build the project with new GHC now? I never used cabal before, `stack ghci` still runs 8.0.2 instead of 8.2.2. Installed GHC 8.2.2 does not correspond to .yaml file LTS - maybe this is a reason why old 8.0.2 is stil used...

When I try cabal build/new-build/repl I get:

cabal: The program 'ghc' version >=6.4 is required but it could not be found.

So, cabal does not know about installed GHC versions (at least 8.0.2, used by stack). I tried --require-sandbox but without success.

...

On Tue, Dec 12, 2017 at 01:56:03PM +0200, Baa wrote: > Would somebody explain me what is wrong here and how I can > test a project with new 8.2.2 GHC?

Hello Paul, I don't think stack lts has 8.2.2 just yet. Use a nightly or download/install ghc from here and compile your project with the new `cabal new-build`.

[1] https://www.haskell.org/ghc/download_ghc_8_2_2.html#binaries

_______________________________________________ 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

_______________________________________________ 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