Compiler diagnostics improvement wishlist

[petrochenkov]

The first module reform thread had a great user story about how missing help/suggestions make learning module system harder than it needs to be:

Revisiting Rust's modules

I think myself that the biggest issue with Rust’s module system is language not helpful enough if you get it wrong unlike other parts of a language, which is very likely if you are learning Rust. When making a new project in Rust, a following tree is created. |-- Cargo.tml `-- src `-- lib.rs src is encouraging in saying to an user - hey, put more stuff here - this is a good design here as it makes it clear that you can put more files - too bad that rest of the compiler doesn’t work togeth…

I think all the items in that report should be covered by diagnostics.