Static type checking

@kcf-jackson has created the {typeChecker} package, an experimental static type checker for R. I had a try at integrating it into {languageserver}, in the types branch of my fork. It calls {typeChecker} alongside {lintr}, and returns the results of both as diagnostics.

Here it is in action with VS Code. The type checking problems are underlined, and the problem details are shown in the terminal.

Installation:

# install.packages("remotes")
remotes::install_github("kcf-jackson/typeChecker")
remotes::install_github("andycraig/languageserver@types")

It currently works on single files only, so it won't type check functions declared in one file but used in another.

Since type annotations are experimental for R I'm not sure we'd want to merge my types branch into master at this stage. But it's there for anyone who wants to try it out. My plan is to periodically rebase it onto the master branch to keep it up to date.

Start with the integration described in the issue and compare the types branch of the fork with master. Review how {typeChecker} is called alongside {lintr} and returns diagnostics, then determine whether single-file checking and experimental R type annotations are sufficiently stable for an integration; done means an agreed direction for bringing this work into the project.