Designers of Elm want their compiler to produce friendly error messages. They show some examples of helpful error messages from their newer compiler on the blog post.
Compilers as Assistants
One of Elm’s goals is to change our relationship with compilers. Compilers should be assistants, not adversaries. A compiler should not just detect bugs, it should then help you understand why there is a bug. It should not berate you in a robot voice, it should give you specific hints that help you write better code. Ultimately, a compiler should make programming faster and more fun!