[Haskell-beginners] Version mismatch with Stack

[Baa]

Hello!

I have library: mylib. And application: myapp. Library will use
Cardinality package. So, I added to mylib's stack.yaml:


==added===
extra-deps:
- https://hackage.haskell.org/package/Cardinality-0.2/Cardinality-0.2.tar.gz

# Override default flag values for local packages and extra-deps
flags:
  Cardinality:
    allow-never: true
===end-of-added===


and I added to mylib's cabal file:


===added===
    build-depends:  ...
                    ... 
                    , Cardinality
===end-of-added===



Seems that it's compiling. OK, now I try to build myapp, which early
was building without any problems (it depends on mylib). But I get
error:


===error===
    Cardinality must match -any, but the stack configuration has no specified version (latest matching version is 0.2)
needed since mylib is a build target.

Some potential ways to resolve this:

  * Recommended action: try adding the following to your extra-deps
    in /xxxxx/myapp/stack.yaml:

- Cardinality-0.2

  * 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.
===end-of-error===


So, what am I doing wrongly? Why stack want adding of the same things
in myapp's stack.yaml which were already added in mylib's stack.yaml?!


/Best regards, Paul