The code refers to a trait that is not in scope.
Erroneous code example:
struct Foo; impl SomeTrait for Foo {} // error: trait `SomeTrait` is not in scope
Please verify that the name of the trait wasn't misspelled and ensure that it was imported. Example:
# #[cfg(for_demonstration_only)] // solution 1: use some_file::SomeTrait; // solution 2: trait SomeTrait { // some functions } struct Foo; impl SomeTrait for Foo { // ok! // implements functions }