Auto merge of #142020 - matthiaskrgr:rollup-8g1r496, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #141271 (Streamline some attr parsing APIs)
 - #141570 (Fix incorrect eq_unspanned in TokenStream)
 - #141857 (coretests: move float tests from num to floats module and use a more flexible macro to generate them)
 - #141893 (remove `f16: From<u16>`)
 - #141924 (Lightly tweak docs for BTree{Map,Set}::extract_if)
 - #141939 (exact_div: add tests)
 - #141959 (Add more missing 2015 edition directives)
 - #142002 (redesign stage 0 std follow-ups part2)
 - #142007 (Improve some `Visitor` comments.)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_ast/src/tokenstream.rs

@@ -57,7 +57,9 @@ impl TokenTree {
         match (self, other) {
             (TokenTree::Token(token, _), TokenTree::Token(token2, _)) => token.kind == token2.kind,
             (TokenTree::Delimited(.., delim, tts), TokenTree::Delimited(.., delim2, tts2)) => {
-                delim == delim2 && tts.eq_unspanned(tts2)
+                delim == delim2
+                    && tts.len() == tts2.len()
+                    && tts.iter().zip(tts2.iter()).all(|(a, b)| a.eq_unspanned(b))
             }
             _ => false,
         }
@@ -694,18 +696,6 @@ impl TokenStream {
         TokenStreamIter::new(self)
     }
 
-    /// Compares two `TokenStream`s, checking equality without regarding span information.
-    pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
-        let mut iter1 = self.iter();
-        let mut iter2 = other.iter();
-        for (tt1, tt2) in iter::zip(&mut iter1, &mut iter2) {
-            if !tt1.eq_unspanned(tt2) {
-                return false;
-            }
-        }
-        iter1.next().is_none() && iter2.next().is_none()
-    }
-
     /// Create a token stream containing a single token with alone spacing. The
     /// spacing used for the final token in a constructed stream doesn't matter
     /// because it's never used. In practice we arbitrarily use

compiler/rustc_ast/src/visit.rs

@@ -121,6 +121,10 @@ pub enum LifetimeCtxt {
 /// explicitly, you need to override each method. (And you also need
 /// to monitor future changes to `Visitor` in case a new method with a
 /// new default implementation gets introduced.)
+///
+/// Every `walk_*` method uses deconstruction to access fields of structs and
+/// enums. This will result in a compile error if a field is added, which makes
+/// it more likely the appropriate visit call will be added for it.
 pub trait Visitor<'ast>: Sized {
     /// The result type of the `visit_*` methods. Can be either `()`,
     /// or `ControlFlow<T>`.

compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs

@@ -53,7 +53,7 @@ fn parse_unstable<'a>(
 
     for param in list.mixed() {
         let param_span = param.span();
-        if let Some(ident) = param.meta_item().and_then(|i| i.path_without_args().word()) {
+        if let Some(ident) = param.meta_item().and_then(|i| i.path().word()) {
             res.push(ident.name);
         } else {
             cx.emit_err(session_diagnostics::ExpectsFeatures {

compiler/rustc_attr_parsing/src/attributes/deprecation.rs

@@ -79,7 +79,7 @@ impl SingleAttributeParser for DeprecationParser {
                     return None;
                 };
 
-                let ident_name = param.path_without_args().word_sym();
+                let ident_name = param.path().word_sym();
 
                 match ident_name {
                     Some(name @ sym::since) => {
@@ -102,7 +102,7 @@ impl SingleAttributeParser for DeprecationParser {
                     _ => {
                         cx.emit_err(session_diagnostics::UnknownMetaItem {
                             span: param_span,
-                            item: param.path_without_args().to_string(),
+                            item: param.path().to_string(),
                             expected: if features.deprecated_suggestion() {
                                 &["since", "note", "suggestion"]
                             } else {

compiler/rustc_attr_parsing/src/attributes/repr.rs

@@ -96,7 +96,7 @@ fn parse_repr(cx: &AcceptContext<'_>, param: &MetaItemParser<'_>) -> Option<Repr
 
     // FIXME(jdonszelmann): invert the parsing here to match on the word first and then the
     // structure.
-    let (name, ident_span) = if let Some(ident) = param.path_without_args().word() {
+    let (name, ident_span) = if let Some(ident) = param.path().word() {
         (Some(ident.name), ident.span)
     } else {
         (None, DUMMY_SP)

compiler/rustc_attr_parsing/src/attributes/stability.rs

@@ -204,7 +204,7 @@ fn insert_value_into_option_or_error(
     if item.is_some() {
         cx.emit_err(session_diagnostics::MultipleItem {
             span: param.span(),
-            item: param.path_without_args().to_string(),
+            item: param.path().to_string(),
         });
         None
     } else if let Some(v) = param.args().name_value()
@@ -242,13 +242,13 @@ pub(crate) fn parse_stability(
             return None;
         };
 
-        match param.path_without_args().word_sym() {
+        match param.path().word_sym() {
             Some(sym::feature) => insert_value_into_option_or_error(cx, &param, &mut feature)?,
             Some(sym::since) => insert_value_into_option_or_error(cx, &param, &mut since)?,
             _ => {
                 cx.emit_err(session_diagnostics::UnknownMetaItem {
                     span: param_span,
-                    item: param.path_without_args().to_string(),
+                    item: param.path().to_string(),
                     expected: &["feature", "since"],
                 });
                 return None;
@@ -310,7 +310,7 @@ pub(crate) fn parse_unstability(
             return None;
         };
 
-        match param.path_without_args().word_sym() {
+        match param.path().word_sym() {
             Some(sym::feature) => insert_value_into_option_or_error(cx, &param, &mut feature)?,
             Some(sym::reason) => insert_value_into_option_or_error(cx, &param, &mut reason)?,
             Some(sym::issue) => {
@@ -349,7 +349,7 @@ pub(crate) fn parse_unstability(
             _ => {
                 cx.emit_err(session_diagnostics::UnknownMetaItem {
                     span: param.span(),
-                    item: param.path_without_args().to_string(),
+                    item: param.path().to_string(),
                     expected: &["feature", "reason", "issue", "soft", "implied_by"],
                 });
                 return None;

compiler/rustc_attr_parsing/src/context.rs

@@ -264,7 +264,8 @@ impl<'sess> AttributeParser<'sess> {
                 // }
                 ast::AttrKind::Normal(n) => {
                     let parser = MetaItemParser::from_attr(n, self.dcx());
-                    let (path, args) = parser.deconstruct();
+                    let path = parser.path();
+                    let args = parser.args();
                     let parts = path.segments().map(|i| i.name).collect::<Vec<_>>();
 
                     if let Some(accept) = ATTRIBUTE_MAPPING.0.get(parts.as_slice()) {

compiler/rustc_attr_parsing/src/parser.rs

@@ -252,35 +252,18 @@ impl<'a> MetaItemParser<'a> {
         }
     }
 
-    /// Gets just the path, without the args.
-    pub fn path_without_args(&self) -> PathParser<'a> {
-        self.path.clone()
-    }
-
-    /// Gets just the args parser, without caring about the path.
-    pub fn args(&self) -> &ArgParser<'a> {
-        &self.args
-    }
-
-    pub fn deconstruct(&self) -> (PathParser<'a>, &ArgParser<'a>) {
-        (self.path_without_args(), self.args())
-    }
-
-    /// Asserts that this MetaItem starts with a path. Some examples:
+    /// Gets just the path, without the args. Some examples:
     ///
     /// - `#[rustfmt::skip]`: `rustfmt::skip` is a path
     /// - `#[allow(clippy::complexity)]`: `clippy::complexity` is a path
     /// - `#[inline]`: `inline` is a single segment path
-    pub fn path(&self) -> (PathParser<'a>, &ArgParser<'a>) {
-        self.deconstruct()
+    pub fn path(&self) -> &PathParser<'a> {
+        &self.path
     }
 
-    /// Asserts that this MetaItem starts with a word, or single segment path.
-    /// Doesn't return the args parser.
-    ///
-    /// For examples. see [`Self::word`]
-    pub fn word_without_args(&self) -> Option<Ident> {
-        Some(self.word()?.0)
+    /// Gets just the args parser, without caring about the path.
+    pub fn args(&self) -> &ArgParser<'a> {
+        &self.args
     }
 
     /// Asserts that this MetaItem starts with a word, or single segment path.
@@ -289,23 +272,8 @@ impl<'a> MetaItemParser<'a> {
     /// - `#[inline]`: `inline` is a word
     /// - `#[rustfmt::skip]`: `rustfmt::skip` is a path,
     ///   and not a word and should instead be parsed using [`path`](Self::path)
-    pub fn word(&self) -> Option<(Ident, &ArgParser<'a>)> {
-        let (path, args) = self.deconstruct();
-        Some((path.word()?, args))
-    }
-
-    /// Asserts that this MetaItem starts with some specific word.
-    ///
-    /// See [`word`](Self::word) for examples of what a word is.
     pub fn word_is(&self, sym: Symbol) -> Option<&ArgParser<'a>> {
-        self.path_without_args().word_is(sym).then(|| self.args())
-    }
-
-    /// Asserts that this MetaItem starts with some specific path.
-    ///
-    /// See [`word`](Self::path) for examples of what a word is.
-    pub fn path_is(&self, segments: &[Symbol]) -> Option<&ArgParser<'a>> {
-        self.path_without_args().segments_is(segments).then(|| self.args())
+        self.path().word_is(sym).then(|| self.args())
     }
 }
 
@@ -548,7 +516,7 @@ impl<'a> MetaItemListParser<'a> {
     }
 
     /// Lets you pick and choose as what you want to parse each element in the list
-    pub fn mixed<'s>(&'s self) -> impl Iterator<Item = &'s MetaItemOrLitParser<'a>> + 's {
+    pub fn mixed(&self) -> impl Iterator<Item = &MetaItemOrLitParser<'a>> {
         self.sub_parsers.iter()
     }
 
@@ -560,20 +528,6 @@ impl<'a> MetaItemListParser<'a> {
         self.len() == 0
     }
 
-    /// Asserts that every item in the list is another list starting with a word.
-    ///
-    /// See [`MetaItemParser::word`] for examples of words.
-    pub fn all_word_list<'s>(&'s self) -> Option<Vec<(Ident, &'s ArgParser<'a>)>> {
-        self.mixed().map(|i| i.meta_item()?.word()).collect()
-    }
-
-    /// Asserts that every item in the list is another list starting with a full path.
-    ///
-    /// See [`MetaItemParser::path`] for examples of paths.
-    pub fn all_path_list<'s>(&'s self) -> Option<Vec<(PathParser<'a>, &'s ArgParser<'a>)>> {
-        self.mixed().map(|i| Some(i.meta_item()?.path())).collect()
-    }
-
     /// Returns Some if the list contains only a single element.
     ///
     /// Inside the Some is the parser to parse this single element.

compiler/rustc_hir/src/intravisit.rs

@@ -200,6 +200,10 @@ use nested_filter::NestedFilter;
 /// explicitly, you need to override each method. (And you also need
 /// to monitor future changes to `Visitor` in case a new method with a
 /// new default implementation gets introduced.)
+///
+/// Every `walk_*` method uses deconstruction to access fields of structs and
+/// enums. This will result in a compile error if a field is added, which makes
+/// it more likely the appropriate visit call will be added for it.
 pub trait Visitor<'v>: Sized {
     // This type should not be overridden, it exists for convenient usage as `Self::MaybeTyCtxt`.
     type MaybeTyCtxt: HirTyCtxt<'v> = <Self::NestedFilter as NestedFilter<'v>>::MaybeTyCtxt;
@@ -1201,7 +1205,6 @@ pub fn walk_trait_item<'v, V: Visitor<'v>>(
     visitor: &mut V,
     trait_item: &'v TraitItem<'v>,
 ) -> V::Result {
-    // N.B., deliberately force a compilation error if/when new fields are added.
     let TraitItem { ident, generics, ref defaultness, ref kind, span, owner_id: _ } = *trait_item;
     let hir_id = trait_item.hir_id();
     try_visit!(visitor.visit_ident(ident));
@@ -1240,7 +1243,6 @@ pub fn walk_trait_item_ref<'v, V: Visitor<'v>>(
     visitor: &mut V,
     trait_item_ref: &'v TraitItemRef,
 ) -> V::Result {
-    // N.B., deliberately force a compilation error if/when new fields are added.
     let TraitItemRef { id, ident, ref kind, span: _ } = *trait_item_ref;
     try_visit!(visitor.visit_nested_trait_item(id));
     try_visit!(visitor.visit_ident(ident));
@@ -1251,7 +1253,6 @@ pub fn walk_impl_item<'v, V: Visitor<'v>>(
     visitor: &mut V,
     impl_item: &'v ImplItem<'v>,
 ) -> V::Result {
-    // N.B., deliberately force a compilation error if/when new fields are added.
     let ImplItem {
         owner_id: _,
         ident,
@@ -1286,7 +1287,6 @@ pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(
     visitor: &mut V,
     foreign_item_ref: &'v ForeignItemRef,
 ) -> V::Result {
-    // N.B., deliberately force a compilation error if/when new fields are added.
     let ForeignItemRef { id, ident, span: _ } = *foreign_item_ref;
     try_visit!(visitor.visit_nested_foreign_item(id));
     visitor.visit_ident(ident)
@@ -1296,7 +1296,6 @@ pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(
     visitor: &mut V,
     impl_item_ref: &'v ImplItemRef,
 ) -> V::Result {
-    // N.B., deliberately force a compilation error if/when new fields are added.
     let ImplItemRef { id, ident, ref kind, span: _, trait_item_def_id: _ } = *impl_item_ref;
     try_visit!(visitor.visit_nested_impl_item(id));
     try_visit!(visitor.visit_ident(ident));

compiler/rustc_middle/src/thir/visit.rs

@@ -3,6 +3,9 @@ use super::{
     Pat, PatKind, Stmt, StmtKind, Thir,
 };
 
+/// Every `walk_*` method uses deconstruction to access fields of structs and
+/// enums. This will result in a compile error if a field is added, which makes
+/// it more likely the appropriate visit call will be added for it.
 pub trait Visitor<'thir, 'tcx: 'thir>: Sized {
     fn thir(&self) -> &'thir Thir<'tcx>;
 

compiler/rustc_parse/src/parser/tokenstream/tests.rs

@@ -14,6 +14,10 @@ fn sp(a: u32, b: u32) -> Span {
     Span::with_root_ctxt(BytePos(a), BytePos(b))
 }
 
+fn cmp_token_stream(a: &TokenStream, b: &TokenStream) -> bool {
+    a.len() == b.len() && a.iter().zip(b.iter()).all(|(x, y)| x.eq_unspanned(y))
+}
+
 #[test]
 fn test_concat() {
     create_default_session_globals_then(|| {
@@ -25,7 +29,7 @@ fn test_concat() {
         eq_res.push_stream(test_snd);
         assert_eq!(test_res.iter().count(), 5);
         assert_eq!(eq_res.iter().count(), 5);
-        assert_eq!(test_res.eq_unspanned(&eq_res), true);
+        assert_eq!(cmp_token_stream(&test_res, &eq_res), true);
     })
 }
 
@@ -104,7 +108,7 @@ fn test_dotdotdot() {
         stream.push_tree(TokenTree::token_joint(token::Dot, sp(0, 1)));
         stream.push_tree(TokenTree::token_joint(token::Dot, sp(1, 2)));
         stream.push_tree(TokenTree::token_alone(token::Dot, sp(2, 3)));
-        assert!(stream.eq_unspanned(&string_to_ts("...")));
+        assert!(cmp_token_stream(&stream, &string_to_ts("...")));
         assert_eq!(stream.iter().count(), 1);
     })
 }

library/alloc/src/collections/btree/map.rs

@@ -1416,18 +1416,18 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
     ///
     /// # Examples
     ///
-    /// Splitting a map into even and odd keys, reusing the original map:
-    ///
     /// ```
     /// #![feature(btree_extract_if)]
     /// use std::collections::BTreeMap;
     ///
+    /// // Splitting a map into even and odd keys, reusing the original map:
     /// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
     /// let evens: BTreeMap<_, _> = map.extract_if(.., |k, _v| k % 2 == 0).collect();
     /// let odds = map;
     /// assert_eq!(evens.keys().copied().collect::<Vec<_>>(), [0, 2, 4, 6]);
     /// assert_eq!(odds.keys().copied().collect::<Vec<_>>(), [1, 3, 5, 7]);
     ///
+    /// // Splitting a map into low and high halves, reusing the original map:
     /// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
     /// let low: BTreeMap<_, _> = map.extract_if(0..4, |_k, _v| true).collect();
     /// let high = map;

library/alloc/src/collections/btree/set.rs

@@ -1201,21 +1201,21 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     /// [`retain`]: BTreeSet::retain
     /// # Examples
     ///
-    /// Splitting a set into even and odd values, reusing the original set:
-    ///
     /// ```
     /// #![feature(btree_extract_if)]
     /// use std::collections::BTreeSet;
     ///
+    /// // Splitting a set into even and odd values, reusing the original set:
     /// let mut set: BTreeSet<i32> = (0..8).collect();
     /// let evens: BTreeSet<_> = set.extract_if(.., |v| v % 2 == 0).collect();
     /// let odds = set;
     /// assert_eq!(evens.into_iter().collect::<Vec<_>>(), vec![0, 2, 4, 6]);
     /// assert_eq!(odds.into_iter().collect::<Vec<_>>(), vec![1, 3, 5, 7]);
     ///
-    /// let mut map: BTreeSet<i32> = (0..8).collect();
-    /// let low: BTreeSet<_> = map.extract_if(0..4, |_v| true).collect();
-    /// let high = map;
+    /// // Splitting a set into low and high halves, reusing the original set:
+    /// let mut set: BTreeSet<i32> = (0..8).collect();
+    /// let low: BTreeSet<_> = set.extract_if(0..4, |_v| true).collect();
+    /// let high = set;
     /// assert_eq!(low.into_iter().collect::<Vec<_>>(), [0, 1, 2, 3]);
     /// assert_eq!(high.into_iter().collect::<Vec<_>>(), [4, 5, 6, 7]);
     /// ```

library/core/src/convert/num.rs

@@ -175,7 +175,6 @@ impl_from!(u8 => f16, #[stable(feature = "lossless_float_conv", since = "1.6.0")
 impl_from!(u8 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 impl_from!(u8 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 impl_from!(u8 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
-impl_from!(u16 => f16, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 impl_from!(u16 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 impl_from!(u16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
 impl_from!(u16 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);