Report usage of lib features in ast validation

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -607,8 +607,7 @@ fn maybe_stage_features(sess: &Session, features: &Features, krate: &ast::Crate)
     // does not check the same for lib features unless there's at least one
     // declared lang feature
     if !sess.opts.unstable_features.is_nightly_build() {
-        let lang_features = &features.declared_lang_features;
-        if lang_features.len() == 0 {
+        if features.declared_features.is_empty() {
             return;
         }
         for attr in krate.attrs.iter().filter(|attr| attr.has_name(sym::feature)) {
@@ -624,7 +623,8 @@ fn maybe_stage_features(sess: &Session, features: &Features, krate: &ast::Crate)
                 attr.meta_item_list().into_iter().flatten().flat_map(|nested| nested.ident())
             {
                 let name = ident.name;
-                let stable_since = lang_features
+                let stable_since = features
+                    .declared_lang_features
                     .iter()
                     .flat_map(|&(feature, _, since)| if feature == name { since } else { None })
                     .next();

compiler/rustc_passes/messages.ftl

@@ -290,9 +290,6 @@ passes_export_name =
 passes_extern_main =
     the `main` function cannot be declared in an `extern` block
 
-passes_feature_only_on_nightly =
-    `#![feature]` may not be used on the {$release_channel} release channel
-
 passes_feature_previously_declared =
     feature `{$feature}` is declared {$declared}, but was previously declared {$prev_declared}
 

compiler/rustc_passes/src/errors.rs

@@ -1492,14 +1492,6 @@ pub struct TraitImplConstStable {
     pub span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(passes_feature_only_on_nightly, code = E0554)]
-pub struct FeatureOnlyOnNightly {
-    #[primary_span]
-    pub span: Span,
-    pub release_channel: &'static str,
-}
-
 #[derive(Diagnostic)]
 #[diag(passes_unknown_feature, code = E0635)]
 pub struct UnknownFeature {

compiler/rustc_passes/src/stability.rs

@@ -936,12 +936,6 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
     let declared_lib_features = &tcx.features().declared_lib_features;
     let mut remaining_lib_features = FxIndexMap::default();
     for (feature, span) in declared_lib_features {
-        if !tcx.sess.opts.unstable_features.is_nightly_build() {
-            tcx.dcx().emit_err(errors::FeatureOnlyOnNightly {
-                span: *span,
-                release_channel: env!("CFG_RELEASE_CHANNEL"),
-            });
-        }
         if remaining_lib_features.contains_key(&feature) {
             // Warn if the user enables a lib feature multiple times.
             tcx.dcx().emit_err(errors::DuplicateFeatureErr { span: *span, feature: *feature });