Initial commit working on edition based method disambiguation

compiler/rustc_attr/src/builtin.rs

@@ -117,7 +117,7 @@ pub struct ConstStability {
 pub enum StabilityLevel {
     // Reason for the current stability level and the relevant rust-lang issue
     Unstable { reason: Option<Symbol>, issue: Option<NonZeroU32>, is_soft: bool },
-    Stable { since: Symbol },
+    Stable { since: Symbol, edition: Option<Symbol> },
 }
 
 impl StabilityLevel {
@@ -348,6 +348,7 @@ where
 
                     let mut feature = None;
                     let mut since = None;
+                    let mut edition = None;
                     for meta in metas {
                         match meta {
                             NestedMetaItem::MetaItem(mi) => match mi.name_or_empty() {
@@ -361,6 +362,11 @@ where
                                         continue 'outer;
                                     }
                                 }
+                                sym::edition => {
+                                    if !get(mi, &mut edition) {
+                                        continue 'outer;
+                                    }
+                                }
                                 _ => {
                                     handle_errors(
                                         &sess.parse_sess,
@@ -386,7 +392,7 @@ where
 
                     match (feature, since) {
                         (Some(feature), Some(since)) => {
-                            let level = Stable { since };
+                            let level = Stable { since, edition };
                             if sym::stable == meta_name {
                                 stab = Some((Stability { level, feature }, attr.span));
                             } else {

compiler/rustc_passes/src/stability.rs

@@ -224,7 +224,7 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
 
             // Check if deprecated_since < stable_since. If it is,
             // this is *almost surely* an accident.
-            if let (&Some(dep_since), &attr::Stable { since: stab_since }) =
+            if let (&Some(dep_since), &attr::Stable { since: stab_since, ..}) =
                 (&depr.as_ref().and_then(|(d, _)| d.since), &stab.level)
             {
                 // Explicit version of iter::order::lt to handle parse errors properly

compiler/rustc_span/src/symbol.rs

@@ -613,6 +613,7 @@ symbols! {
         dyn_metadata,
         dyn_trait,
         e,
+        edition,
         edition_macro_pats,
         edition_panic,
         eh_catch_typeinfo,

src/librustdoc/html/render/mod.rs

@@ -845,7 +845,7 @@ fn render_stability_since_raw(
     }
 
     let const_title_and_stability = match const_stability {
-        Some(ConstStability { level: StabilityLevel::Stable { since }, .. })
+        Some(ConstStability { level: StabilityLevel::Stable { since, .. }, .. })
             if Some(since) != containing_const_ver =>
         {
             Some((format!("const since {}", since), format!("const: {}", since)))

src/test/ui/stability-attribute/auxiliary/edition-field-std.rs

@@ -0,0 +1,13 @@
+#![feature(staged_api)]
+#![stable(feature = "intersperse", since = "1.0.0", edition = "2021")]
+
+#[stable(feature = "intersperse", since = "1.0.0", edition = "2021")]
+pub struct Intersperse;
+
+#[stable(feature = "intersperse", since = "1.0.0", edition = "2021")]
+pub trait Iterator {
+    #[stable(feature = "intersperse", since = "1.0.0", edition = "2021")]
+    fn intersperse(&self, separator: ()) -> Intersperse {
+        unimplemented!()
+    }
+}

src/test/ui/stability-attribute/edition-field.rs

@@ -0,0 +1,24 @@
+// aux-build:edition-field-std.rs
+
+extern crate edition_field_std;
+use edition_field_std::Iterator;
+
+struct Intersperse;
+
+trait Itertools {
+    fn intersperse(&self, separator: ()) -> Intersperse {
+        unimplemented!()
+    }
+}
+
+impl<T> Itertools for T
+where
+    T: Iterator {}
+
+struct MyIterator;
+impl Iterator for MyIterator {}
+
+fn main() {
+    let it = MyIterator;
+    let _intersperse = it.intersperse(());
+}

src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

@@ -355,7 +355,7 @@ fn check_terminator<'a, 'tcx>(
 fn is_const_fn(tcx: TyCtxt<'_>, def_id: DefId, msrv: Option<&RustcVersion>) -> bool {
     tcx.is_const_fn(def_id)
         && tcx.lookup_const_stability(def_id).map_or(true, |const_stab| {
-            if let rustc_attr::StabilityLevel::Stable { since } = const_stab.level {
+            if let rustc_attr::StabilityLevel::Stable { since, ..} = const_stab.level {
                 // Checking MSRV is manually necessary because `rustc` has no such concept. This entire
                 // function could be removed if `rustc` provided a MSRV-aware version of `is_const_fn`.
                 // as a part of an unimplemented MSRV check https://github.com/rust-lang/rust/issues/65262.