Remove edition umbrella features.

compiler/rustc_expand/src/config.rs

@@ -1,8 +1,8 @@
 //! Conditional compilation stripping.
 
 use crate::errors::{
-    FeatureIncludedInEdition, FeatureNotAllowed, FeatureRemoved, FeatureRemovedReason, InvalidCfg,
-    MalformedFeatureAttribute, MalformedFeatureAttributeHelp, RemoveExprNotSupported,
+    FeatureNotAllowed, FeatureRemoved, FeatureRemovedReason, InvalidCfg, MalformedFeatureAttribute,
+    MalformedFeatureAttributeHelp, RemoveExprNotSupported,
 };
 use rustc_ast::ptr::P;
 use rustc_ast::token::{Delimiter, Token, TokenKind};
@@ -13,13 +13,11 @@ use rustc_ast::NodeId;
 use rustc_ast::{self as ast, AttrStyle, Attribute, HasAttrs, HasTokens, MetaItem};
 use rustc_attr as attr;
 use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
-use rustc_data_structures::fx::FxHashSet;
 use rustc_feature::Features;
 use rustc_feature::{ACCEPTED_FEATURES, REMOVED_FEATURES, UNSTABLE_FEATURES};
 use rustc_parse::validate_attr;
 use rustc_session::parse::feature_err;
 use rustc_session::Session;
-use rustc_span::edition::ALL_EDITIONS;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use thin_vec::ThinVec;
@@ -48,42 +46,6 @@ pub fn features(sess: &Session, krate_attrs: &[Attribute], crate_name: Symbol) -
 
     let mut features = Features::default();
 
-    // The edition from `--edition`.
-    let crate_edition = sess.edition();
-
-    // The maximum of (a) the edition from `--edition` and (b) any edition
-    // umbrella feature-gates declared in the code.
-    // - E.g. if `crate_edition` is 2015 but `rust_2018_preview` is present,
-    //   `feature_edition` is 2018
-    let mut features_edition = crate_edition;
-    for attr in krate_attrs {
-        for mi in feature_list(attr) {
-            if mi.is_word() {
-                let name = mi.name_or_empty();
-                let edition = ALL_EDITIONS.iter().find(|e| name == e.feature_name()).copied();
-                if let Some(edition) = edition
-                    && edition > features_edition
-                {
-                    features_edition = edition;
-                }
-            }
-        }
-    }
-
-    // Enable edition-dependent features based on `features_edition`.
-    // - E.g. enable `test_2018_feature` if `features_edition` is 2018 or higher
-    let mut edition_enabled_features = FxHashSet::default();
-    for f in UNSTABLE_FEATURES {
-        if let Some(edition) = f.feature.edition
-            && edition <= features_edition
-        {
-            // FIXME(Manishearth) there is currently no way to set lib features by
-            // edition.
-            edition_enabled_features.insert(f.feature.name);
-            (f.set_enabled)(&mut features);
-        }
-    }
-
     // Process all features declared in the code.
     for attr in krate_attrs {
         for mi in feature_list(attr) {
@@ -108,38 +70,6 @@ pub fn features(sess: &Session, krate_attrs: &[Attribute], crate_name: Symbol) -
                 }
             };
 
-            // If the declared feature is an edition umbrella feature-gate,
-            // warn if it was redundant w.r.t. `crate_edition`.
-            // - E.g. warn if `rust_2018_preview` is declared when
-            //   `crate_edition` is 2018
-            // - E.g. don't warn if `rust_2018_preview` is declared when
-            //   `crate_edition` is 2015.
-            if let Some(&edition) = ALL_EDITIONS.iter().find(|e| name == e.feature_name()) {
-                if edition <= crate_edition {
-                    sess.emit_warning(FeatureIncludedInEdition {
-                        span: mi.span(),
-                        feature: name,
-                        edition,
-                    });
-                }
-                features.set_declared_lang_feature(name, mi.span(), None);
-                continue;
-            }
-
-            // If the declared feature is edition-dependent and was already
-            // enabled due to `feature_edition`, give a warning.
-            // - E.g. warn if `test_2018_feature` is declared when
-            //   `feature_edition` is 2018 or higher.
-            if edition_enabled_features.contains(&name) {
-                sess.emit_warning(FeatureIncludedInEdition {
-                    span: mi.span(),
-                    feature: name,
-                    edition: features_edition,
-                });
-                features.set_declared_lang_feature(name, mi.span(), None);
-                continue;
-            }
-
             // If the declared feature has been removed, issue an error.
             if let Some(f) = REMOVED_FEATURES.iter().find(|f| name == f.feature.name) {
                 sess.emit_err(FeatureRemoved {

compiler/rustc_expand/src/errors.rs

@@ -1,7 +1,6 @@
 use rustc_ast::ast;
 use rustc_macros::Diagnostic;
 use rustc_session::Limit;
-use rustc_span::edition::Edition;
 use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent};
 use rustc_span::{Span, Symbol};
 use std::borrow::Cow;
@@ -168,15 +167,6 @@ pub(crate) struct TakesNoArguments<'a> {
     pub name: &'a str,
 }
 
-#[derive(Diagnostic)]
-#[diag(expand_feature_included_in_edition, code = "E0705")]
-pub(crate) struct FeatureIncludedInEdition {
-    #[primary_span]
-    pub span: Span,
-    pub feature: Symbol,
-    pub edition: Edition,
-}
-
 #[derive(Diagnostic)]
 #[diag(expand_feature_removed, code = "E0557")]
 pub(crate) struct FeatureRemoved<'a> {