cabal-matrix is a matrix builder for cabal. It lets you specify in a flexible way a list of configurations in which something can be built, such as compiler versions, or dependency version restrictions. It will then run the builds in parallel (locally), and present the results in a TUI table where the specific outcomes can be more closely examined. This is useful for inventing and correcting dependency bounds for your package, as well as finding dependency issues in other packages and fixing them.