*** abort because of serious configure-time warning from Cabal

probably I am doing something wrong. I often get this error when building with the `default.nix` that was generated by `stack2nix`:

```
*** abort because of serious configure-time warning from Cabal
```

for example in one case:

```
This package indirectly depends on multiple versions of the same package. This is very likely to cause a compile failure.
package accelerate-llvm-native (accelerate-llvm-native-1.2.0.0-6h9HfY2jTx2VH4bfhr7AT) requires Cabal-2.2.0.1
package proto-lens-protoc (proto-lens-protoc-0.3.1.0-JlEPGIPhQWg4b89HqVvNBT) requires Cabal-2.2.0.1-302vnEvwKg
```

Usually the version *is* the same. I had the same warning with a bunch of other packes, e.g. mtl, text, parsec, stm, which I managed to fix by adding:

```
in compiler.override {
overrides = self: super: builtins.intersectAttrs super {
mtl = null;
text = null;
stm = null;
parsec = null;
llvm-hs = super.llvm-hs.override { llvm-config = pkgs.llvm_5; };
};
initialPackages = stackPackages;
configurationCommon = { ... }: self: super: {};
compilerConfig = self: super: {};
}
```

I would like to understand why this happens and how it can be best avoided. Unfortunately I can't share my whole package to reproduce this. Do you have any idea what this is all about?