Resolve reports arbitrarily many identical copies of an error message

[jseyfried]

The following example reports error: bar is private, and cannot be reexported [E0364] four times.

fn bar() {}
pub use bar as baz;

pub use a::*;
mod a { pub use b::foo; }
mod b { pub use c::foo; }
mod c { pub fn foo() {} }

If the glob import is commented out, it only prints the error once.

[dirk]

I believe this is because we're generating an error every time we encounter this invalid reexport, and in your example that is happening 4 times (once in self, once in a, once in b, and once in c) because we resolve all the imports and exports for the modules (self, a, b, and c). If we reported something like a backtrace for each of these failures it would show that it was happening in each of those modules.