const package:cabal-install-solver

const x y always evaluates to x, ignoring its second argument.

const x = \_ -> x

This function might seem useless at first glance, but it can be very useful in a higher order context.

Examples

>>> const 42 "hello"
42

>>> map (const 42) [0..3]
[42,42,42,42]

The Const functor.

An internal constraint due to compatibility issues with the Setup.hs command line interface requires a maximum upper bound on Cabal

An internal constraint due to compatibility issues with the Setup.hs command line interface requires a minimum lower bound on Cabal

Source of a PackageConstraint.

Flag specified on the command line.

Constraint specified by a config file, a command line flag, or a user target, when a more specific source is not known.

Internal constraint used by cabal freeze.

Main config file, which is ~.cabalconfig by default.

Constraint introduced by --enable-multi-repl, which requires features from Cabal >= 3.11

Internal requirement to use installed versions of packages like ghc-prim.

Constraint introduced by --enable-profiling-shared, which requires features from Cabal >= 3.13

Local cabal.project file

The source of the constraint is not specified.

User config file, which is ./cabal.config by default.

Target specified by the user, e.g., cabal install package-0.1.0.0 implies package==0.1.0.0.

Constraint introduced by --with-repl, which requires features from Cabal >= 3.15

Determines to what packages and in what contexts a constraint applies.

The conflict set variable represents a package with a constraint that excluded the specified package and version. For example, the conflict set entry '(P x, VersionConstraintConflict y (mkVersion [2, 0]))' means that package x's constraint on y excluded y-2.0.