Rigid type variables

The phrase rigid type variable shows up in several contexts in GHC error messages. Often, when it appears, it’s in a context where you know that the type variable it refers to is totally unconstrained, or parametrically polymorphic, and you may have found yourself wondering what is exactly is meant by rigid? How can something that could be anything be “rigid”?

This article will be released soon!

Type Classes offers courses and projects to get you started and make you an expert in FP with Haskell. For $29/month, you get access to the complete archive and all the latest content.