elm-lint
plugin that provides rules to detect unused functions and types in your Elm files.
NoUnused.Variables - Reports unused top-level variables and types, imports and imported variables and types.NoUnused.CustomTypeConstructors - Reports unused constructors for a custom type.Since elm-lint only works in the scope of a single file, these rules
will not report elements that are exposed but not used anywhere in the project.
If you wish those to be reported, check out elm-xref.