https://doc.rust-lang.org/beta/nightly-rustc/rustc_session/errors/struct.FeatureDiagnosticSuggestion.html
FeatureDiagnosticSuggestion in rustc_session::errors - Rust
API documentation for the Rust `FeatureDiagnosticSuggestion` struct in crate `rustc_session`.
rustcsessionerrors