Come on. If you’re going to spend your life developing julia code, why not. Otherwise, just no. I never read a single manual from beginning to end, and pretty much nobody else does this.
In this case, the error message is technically correct but very low-level and confusing to new users. @jules I feel your suggestion is too verbose and beginner-oriented, but there could be a middle ground, like “Invalid redefinition of existing struct MyStruct”. Same probably also goes for const a=1; a = 1.0. If you could make a list of error messages you find confusing and open an issue/PR with that, I think it could be very helpful!