Some type parameters have the same name.
Erroneous code example:
fn f<T, T>(s: T, u: T) {} // error: the name `T` is already used for a generic
// parameter in this item's generic parametersPlease verify that none of the type parameters are misspelled, and rename any clashing parameters. Example:
fn f<T, Y>(s: T, u: Y) {} // ok!Type parameters in an associated item also cannot shadow parameters from the containing item:
trait Foo<T> {
fn do_something(&self) -> T;
fn do_something_else<T: Clone>(&self, bar: T);
}