diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs index 75bd8880b34..b6b349e4a80 100644 --- a/compiler/rustc_session/src/config.rs +++ b/compiler/rustc_session/src/config.rs @@ -18,7 +18,7 @@ use rustc_serialize::json; use crate::parse::CrateConfig; use rustc_feature::UnstableFeatures; -use rustc_span::edition::{Edition, DEFAULT_EDITION, EDITION_NAME_LIST}; +use rustc_span::edition::{Edition, DEFAULT_EDITION, EDITION_NAME_LIST, LATEST_STABLE_EDITION}; use rustc_span::source_map::{FileName, FilePathMapping}; use rustc_span::symbol::{sym, Symbol}; use rustc_span::SourceFileHashAlgorithm; @@ -1320,13 +1320,16 @@ pub fn parse_crate_edition(matches: &getopts::Matches) -> Edition { }; if !edition.is_stable() && !nightly_options::is_unstable_enabled(matches) { - early_error( - ErrorOutputType::default(), - &format!( - "edition {} is unstable and only available with -Z unstable-options.", - edition, - ), - ) + let is_nightly = nightly_options::match_is_nightly_build(matches); + let msg = if !is_nightly { + format!( + "the crate requires edition {}, but the latest edition supported by this Rust version is {}", + edition, LATEST_STABLE_EDITION + ) + } else { + format!("edition {} is unstable and only available with -Z unstable-options", edition) + }; + early_error(ErrorOutputType::default(), &msg) } edition