Auto merge of #109503 - matthiaskrgr:rollup-cnp7kdd, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #108954 (rustdoc: handle generics better when matching notable traits)
 - #109203 (refactor/feat: refactor identifier parsing a bit)
 - #109213 (Eagerly intern and check CrateNum/StableCrateId collisions)
 - #109358 (rustc: Remove unused `Session` argument from some attribute functions)
 - #109359 (Update stdarch)
 - #109378 (Remove Ty::is_region_ptr)
 - #109423 (Use region-erased self type during IAT selection)
 - #109447 (new solver cleanup + implement coherence)
 - #109501 (make link clickable)

Failed merges:

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

8 files changed, 74 insertions, 37 deletions

diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 6d8380c5fcc..7dbb3f76a0a 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -1471,27 +1471,68 @@ impl Type {
         result
     }
 
-    /// Check if two types are "potentially the same".
+    pub(crate) fn is_borrowed_ref(&self) -> bool {
+        matches!(self, Type::BorrowedRef { .. })
+    }
+
+    /// Check if two types are "the same" for documentation purposes.
+    ///
     /// This is different from `Eq`, because it knows that things like
     /// `Placeholder` are possible matches for everything.
-    pub(crate) fn is_same(&self, other: &Self, cache: &Cache) -> bool {
-        match (self, other) {
+    ///
+    /// This relation is not commutative when generics are involved:
+    ///
+    /// ```ignore(private)
+    /// # // see types/tests.rs:is_same_generic for the real test
+    /// use rustdoc::format::cache::Cache;
+    /// use rustdoc::clean::types::{Type, PrimitiveType};
+    /// let cache = Cache::new(false);
+    /// let generic = Type::Generic(rustc_span::symbol::sym::Any);
+    /// let unit = Type::Primitive(PrimitiveType::Unit);
+    /// assert!(!generic.is_same(&unit, &cache));
+    /// assert!(unit.is_same(&generic, &cache));
+    /// ```
+    ///
+    /// An owned type is also the same as its borrowed variants (this is commutative),
+    /// but `&T` is not the same as `&mut T`.
+    pub(crate) fn is_doc_subtype_of(&self, other: &Self, cache: &Cache) -> bool {
+        // Strip the references so that it can compare the actual types, unless both are references.
+        // If both are references, leave them alone and compare the mutabilities later.
+        let (self_cleared, other_cleared) = if !self.is_borrowed_ref() || !other.is_borrowed_ref() {
+            (self.without_borrowed_ref(), other.without_borrowed_ref())
+        } else {
+            (self, other)
+        };
+        match (self_cleared, other_cleared) {
             // Recursive cases.
             (Type::Tuple(a), Type::Tuple(b)) => {
-                a.len() == b.len() && a.iter().zip(b).all(|(a, b)| a.is_same(b, cache))
+                a.len() == b.len() && a.iter().zip(b).all(|(a, b)| a.is_doc_subtype_of(b, cache))
             }
-            (Type::Slice(a), Type::Slice(b)) => a.is_same(b, cache),
-            (Type::Array(a, al), Type::Array(b, bl)) => al == bl && a.is_same(b, cache),
+            (Type::Slice(a), Type::Slice(b)) => a.is_doc_subtype_of(b, cache),
+            (Type::Array(a, al), Type::Array(b, bl)) => al == bl && a.is_doc_subtype_of(b, cache),
             (Type::RawPointer(mutability, type_), Type::RawPointer(b_mutability, b_type_)) => {
-                mutability == b_mutability && type_.is_same(b_type_, cache)
+                mutability == b_mutability && type_.is_doc_subtype_of(b_type_, cache)
             }
             (
                 Type::BorrowedRef { mutability, type_, .. },
                 Type::BorrowedRef { mutability: b_mutability, type_: b_type_, .. },
-            ) => mutability == b_mutability && type_.is_same(b_type_, cache),
-            // Placeholders and generics are equal to all other types.
+            ) => mutability == b_mutability && type_.is_doc_subtype_of(b_type_, cache),
+            // Placeholders are equal to all other types.
             (Type::Infer, _) | (_, Type::Infer) => true,
-            (Type::Generic(_), _) | (_, Type::Generic(_)) => true,
+            // Generics match everything on the right, but not on the left.
+            // If both sides are generic, this returns true.
+            (_, Type::Generic(_)) => true,
+            (Type::Generic(_), _) => false,
+            // Paths account for both the path itself and its generics.
+            (Type::Path { path: a }, Type::Path { path: b }) => {
+                a.def_id() == b.def_id()
+                    && a.generics()
+                        .zip(b.generics())
+                        .map(|(ag, bg)| {
+                            ag.iter().zip(bg.iter()).all(|(at, bt)| at.is_doc_subtype_of(bt, cache))
+                        })
+                        .unwrap_or(true)
+            }
             // Other cases, such as primitives, just use recursion.
             (a, b) => a
                 .def_id(cache)
diff --git a/src/librustdoc/clean/types/tests.rs b/src/librustdoc/clean/types/tests.rs
index 8f2331785f5..d8c91a96804 100644
--- a/src/librustdoc/clean/types/tests.rs
+++ b/src/librustdoc/clean/types/tests.rs
@@ -69,3 +69,14 @@ fn should_not_trim() {
     run_test("\t    line1  \n\t    line2", "line1  \nline2");
     run_test("    \tline1  \n    \tline2", "line1  \nline2");
 }
+
+#[test]
+fn is_same_generic() {
+    use crate::clean::types::{PrimitiveType, Type};
+    use crate::formats::cache::Cache;
+    let cache = Cache::new(false);
+    let generic = Type::Generic(rustc_span::symbol::sym::Any);
+    let unit = Type::Primitive(PrimitiveType::Unit);
+    assert!(!generic.is_doc_subtype_of(&unit, &cache));
+    assert!(unit.is_doc_subtype_of(&generic, &cache));
+}
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index da1f1cf5ecc..d75d03071f8 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -1294,7 +1294,7 @@ pub(crate) fn notable_traits_button(ty: &clean::Type, cx: &mut Context<'_>) -> O
     if let Some(impls) = cx.cache().impls.get(&did) {
         for i in impls {
             let impl_ = i.inner_impl();
-            if !impl_.for_.without_borrowed_ref().is_same(ty.without_borrowed_ref(), cx.cache()) {
+            if !ty.is_doc_subtype_of(&impl_.for_, cx.cache()) {
                 // Two different types might have the same did,
                 // without actually being the same.
                 continue;
@@ -1330,7 +1330,7 @@ fn notable_traits_decl(ty: &clean::Type, cx: &Context<'_>) -> (String, String) {
 
     for i in impls {
         let impl_ = i.inner_impl();
-        if !impl_.for_.without_borrowed_ref().is_same(ty.without_borrowed_ref(), cx.cache()) {
+        if !ty.is_doc_subtype_of(&impl_.for_, cx.cache()) {
             // Two different types might have the same did,
             // without actually being the same.
             continue;
diff --git a/src/tools/clippy/clippy_lints/src/functions/must_use.rs b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
index eacbf6c6ec9..67877780c0e 100644
--- a/src/tools/clippy/clippy_lints/src/functions/must_use.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
@@ -28,7 +28,7 @@ pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>
         let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
         if let Some(attr) = attr {
             check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr);
-        } else if is_public && !is_proc_macro(cx.sess(), attrs) && !attrs.iter().any(|a| a.has_name(sym::no_mangle)) {
+        } else if is_public && !is_proc_macro(attrs) && !attrs.iter().any(|a| a.has_name(sym::no_mangle)) {
             check_must_use_candidate(
                 cx,
                 sig.decl,
@@ -51,7 +51,7 @@ pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Imp
         if let Some(attr) = attr {
             check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr);
         } else if is_public
-            && !is_proc_macro(cx.sess(), attrs)
+            && !is_proc_macro(attrs)
             && trait_ref_of_method(cx, item.owner_id.def_id).is_none()
         {
             check_must_use_candidate(
@@ -78,7 +78,7 @@ pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Tr
             check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr);
         } else if let hir::TraitFn::Provided(eid) = *eid {
             let body = cx.tcx.hir().body(eid);
-            if attr.is_none() && is_public && !is_proc_macro(cx.sess(), attrs) {
+            if attr.is_none() && is_public && !is_proc_macro(attrs) {
                 check_must_use_candidate(
                     cx,
                     sig.decl,
diff --git a/src/tools/clippy/clippy_utils/src/attrs.rs b/src/tools/clippy/clippy_utils/src/attrs.rs
index 7987a233bdc..bc3d774540a 100644
--- a/src/tools/clippy/clippy_utils/src/attrs.rs
+++ b/src/tools/clippy/clippy_utils/src/attrs.rs
@@ -145,8 +145,8 @@ pub fn get_unique_attr<'a>(
 
 /// Return true if the attributes contain any of `proc_macro`,
 /// `proc_macro_derive` or `proc_macro_attribute`, false otherwise
-pub fn is_proc_macro(sess: &Session, attrs: &[ast::Attribute]) -> bool {
-    attrs.iter().any(|attr| sess.is_proc_macro_attr(attr))
+pub fn is_proc_macro(attrs: &[ast::Attribute]) -> bool {
+    attrs.iter().any(|attr| attr.is_proc_macro_attr())
 }
 
 /// Return true if the attributes contain `#[doc(hidden)]`
diff --git a/src/tools/rustfmt/src/attr.rs b/src/tools/rustfmt/src/attr.rs
index 5648e1254ed..22e45082a9f 100644
--- a/src/tools/rustfmt/src/attr.rs
+++ b/src/tools/rustfmt/src/attr.rs
@@ -2,7 +2,7 @@
 
 use rustc_ast::ast;
 use rustc_ast::HasAttrs;
-use rustc_span::{symbol::sym, Span, Symbol};
+use rustc_span::{symbol::sym, Span};
 
 use self::doc_comment::DocCommentFormatter;
 use crate::comment::{contains_comment, rewrite_doc_comment, CommentStyle};
@@ -19,20 +19,6 @@ use crate::utils::{count_newlines, mk_sp};
 
 mod doc_comment;
 
-pub(crate) fn contains_name(attrs: &[ast::Attribute], name: Symbol) -> bool {
-    attrs.iter().any(|attr| attr.has_name(name))
-}
-
-pub(crate) fn first_attr_value_str_by_name(
-    attrs: &[ast::Attribute],
-    name: Symbol,
-) -> Option<Symbol> {
-    attrs
-        .iter()
-        .find(|attr| attr.has_name(name))
-        .and_then(|attr| attr.value_str())
-}
-
 /// Returns attributes on the given statement.
 pub(crate) fn get_attrs_from_stmt(stmt: &ast::Stmt) -> &[ast::Attribute] {
     stmt.attrs()
diff --git a/src/tools/rustfmt/src/parse/parser.rs b/src/tools/rustfmt/src/parse/parser.rs
index 7ab042506bd..6bc53159b38 100644
--- a/src/tools/rustfmt/src/parse/parser.rs
+++ b/src/tools/rustfmt/src/parse/parser.rs
@@ -2,13 +2,12 @@ use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::path::{Path, PathBuf};
 
 use rustc_ast::token::TokenKind;
-use rustc_ast::{ast, ptr};
+use rustc_ast::{ast, attr, ptr};
 use rustc_errors::Diagnostic;
 use rustc_parse::{new_parser_from_file, parser::Parser as RawParser};
 use rustc_span::{sym, Span};
 use thin_vec::ThinVec;
 
-use crate::attr::first_attr_value_str_by_name;
 use crate::parse::session::ParseSess;
 use crate::Input;
 
@@ -93,7 +92,7 @@ pub(crate) enum ParserError {
 
 impl<'a> Parser<'a> {
     pub(crate) fn submod_path_from_attr(attrs: &[ast::Attribute], path: &Path) -> Option<PathBuf> {
-        let path_sym = first_attr_value_str_by_name(attrs, sym::path)?;
+        let path_sym = attr::first_attr_value_str_by_name(attrs, sym::path)?;
         let path_str = path_sym.as_str();
 
         // On windows, the base path might have the form
diff --git a/src/tools/rustfmt/src/reorder.rs b/src/tools/rustfmt/src/reorder.rs
index 9e4a668aa49..3bddf4c1b6a 100644
--- a/src/tools/rustfmt/src/reorder.rs
+++ b/src/tools/rustfmt/src/reorder.rs
@@ -8,7 +8,7 @@
 
 use std::cmp::{Ord, Ordering};
 
-use rustc_ast::ast;
+use rustc_ast::{ast, attr};
 use rustc_span::{symbol::sym, Span};
 
 use crate::config::{Config, GroupImportsTactic};
@@ -167,7 +167,7 @@ fn rewrite_reorderable_or_regroupable_items(
 }
 
 fn contains_macro_use_attr(item: &ast::Item) -> bool {
-    crate::attr::contains_name(&item.attrs, sym::macro_use)
+    attr::contains_name(&item.attrs, sym::macro_use)
 }
 
 /// Divides imports into three groups, corresponding to standard, external