Reanalyze reports issues that are incorrect for Rescript 12

[konradtho]

Issue

I recently updated a project to use Rescript 12.2.0, and observed some differences in the issues reported by reanalyze coming from Rescript 11.1.4.

Issue described below is reproducible in repo: https://github.com/konradtho/rescript-analyze-issues.

Short version

In the Rescript 12 project I have defined a function with an optional argument used by a React provider.

let doSomethingContext = React.createContext((_arg: string, ~optArg as _: option<string>=?) => ())

module DoSomethingProvider = {
  module Provider = {
    let make = React.Context.provider(doSomethingContext)
  }

  @react.component
  let make = (~children) => {
    let doSomething = (arg: string, ~optArg: option<string>=?) => {
      switch optArg {
        | Some(optArg) => Console.log2(arg, optArg)
        | None => Console.log(arg)
      }
    }

    <Provider value=doSomething>
      {children}
    </Provider>
  }
}

When used by two components: One using the optional argument and one not using the optional argument, you get this output when running yarn rescript-tools reanalyze -dce:

Warning Redundant Optional Argument
  /.../src/App.res:42:5-69
  optional argument action of function ComponentUsingAction.dispatchNotification is always supplied (1 calls)

  Warning Unused Argument
  /.../src/App.res:57:5-69
  optional argument action of function ComponentNotUsingAction.dispatchNotification is never used

  Warning Unused Argument
  /.../src/App.res:13:5-289
  optional argument action of function NotificationProvider.dispatchNotification is never used

  Warning Unused Argument
  /../src/App.res:23:3-75
  optional argument action of function NotificationProvider.useNotification is never used
  
  Analysis reported 4 issues (Warning Redundant Optional Argument:1, Warning Unused Argument:3)

where as running the same command and the same code in a Rescript 11 project gives the output:

Analysis reported 0 issues