Merge commit 'a109190d70' into clippy-subtree-update

clippy_utils/src/consts.rs

@@ -484,10 +484,9 @@ impl<'tcx> ConstEvalCtxt<'tcx> {
             }),
             ExprKind::If(cond, then, ref otherwise) => self.ifthenelse(cond, then, *otherwise),
             ExprKind::Binary(op, left, right) => self.binop(op, left, right),
-            ExprKind::Call(callee, args) => {
+            ExprKind::Call(callee, []) => {
                 // We only handle a few const functions for now.
-                if args.is_empty()
-                    && let ExprKind::Path(qpath) = &callee.kind
+                if let ExprKind::Path(qpath) = &callee.kind
                     && let Some(did) = self.typeck.qpath_res(qpath, callee.hir_id).opt_def_id()
                 {
                     match self.tcx.get_diagnostic_name(did) {

clippy_utils/src/hir_utils.rs

@@ -5,7 +5,7 @@ use crate::tokenize_with_text;
 use rustc_ast::ast::InlineAsmTemplatePiece;
 use rustc_data_structures::fx::FxHasher;
 use rustc_hir::MatchSource::TryDesugar;
-use rustc_hir::def::Res;
+use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{
     ArrayLen, AssocItemConstraint, BinOpKind, BindingMode, Block, BodyId, Closure, ConstArg, ConstArgKind, Expr,
     ExprField, ExprKind, FnRetTy, GenericArg, GenericArgs, HirId, HirIdMap, InlineAsmOperand, LetExpr, Lifetime,
@@ -17,11 +17,33 @@ use rustc_middle::ty::TypeckResults;
 use rustc_span::{BytePos, ExpnKind, MacroKind, Symbol, SyntaxContext, sym};
 use std::hash::{Hash, Hasher};
 use std::ops::Range;
+use std::slice;
 
 /// Callback that is called when two expressions are not equal in the sense of `SpanlessEq`, but
 /// other conditions would make them equal.
 type SpanlessEqCallback<'a> = dyn FnMut(&Expr<'_>, &Expr<'_>) -> bool + 'a;
 
+/// Determines how paths are hashed and compared for equality.
+#[derive(Copy, Clone, Debug, Default)]
+pub enum PathCheck {
+    /// Paths must match exactly and are hashed by their exact HIR tree.
+    ///
+    /// Thus, `std::iter::Iterator` and `Iterator` are not considered equal even though they refer
+    /// to the same item.
+    #[default]
+    Exact,
+    /// Paths are compared and hashed based on their resolution.
+    ///
+    /// They can appear different in the HIR tree but are still considered equal
+    /// and have equal hashes as long as they refer to the same item.
+    ///
+    /// Note that this is currently only partially implemented specifically for paths that are
+    /// resolved before type-checking, i.e. the final segment must have a non-error resolution.
+    /// If a path with an error resolution is encountered, it falls back to the default exact
+    /// matching behavior.
+    Resolution,
+}
+
 /// Type used to check whether two ast are the same. This is different from the
 /// operator `==` on ast types as this operator would compare true equality with
 /// ID and span.
@@ -33,6 +55,7 @@ pub struct SpanlessEq<'a, 'tcx> {
     maybe_typeck_results: Option<(&'tcx TypeckResults<'tcx>, &'tcx TypeckResults<'tcx>)>,
     allow_side_effects: bool,
     expr_fallback: Option<Box<SpanlessEqCallback<'a>>>,
+    path_check: PathCheck,
 }
 
 impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
@@ -42,6 +65,7 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
             maybe_typeck_results: cx.maybe_typeck_results().map(|x| (x, x)),
             allow_side_effects: true,
             expr_fallback: None,
+            path_check: PathCheck::default(),
         }
     }
 
@@ -54,6 +78,16 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
         }
     }
 
+    /// Check paths by their resolution instead of exact equality. See [`PathCheck`] for more
+    /// details.
+    #[must_use]
+    pub fn paths_by_resolution(self) -> Self {
+        Self {
+            path_check: PathCheck::Resolution,
+            ..self
+        }
+    }
+
     #[must_use]
     pub fn expr_fallback(self, expr_fallback: impl FnMut(&Expr<'_>, &Expr<'_>) -> bool + 'a) -> Self {
         Self {
@@ -498,7 +532,7 @@ impl HirEqInterExpr<'_, '_, '_> {
         match (left.res, right.res) {
             (Res::Local(l), Res::Local(r)) => l == r || self.locals.get(&l) == Some(&r),
             (Res::Local(_), _) | (_, Res::Local(_)) => false,
-            _ => over(left.segments, right.segments, |l, r| self.eq_path_segment(l, r)),
+            _ => self.eq_path_segments(left.segments, right.segments),
         }
     }
 
@@ -511,17 +545,39 @@ impl HirEqInterExpr<'_, '_, '_> {
         }
     }
 
-    pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
-        left.len() == right.len() && left.iter().zip(right).all(|(l, r)| self.eq_path_segment(l, r))
+    pub fn eq_path_segments<'tcx>(
+        &mut self,
+        mut left: &'tcx [PathSegment<'tcx>],
+        mut right: &'tcx [PathSegment<'tcx>],
+    ) -> bool {
+        if let PathCheck::Resolution = self.inner.path_check
+            && let Some(left_seg) = generic_path_segments(left)
+            && let Some(right_seg) = generic_path_segments(right)
+        {
+            // If we compare by resolution, then only check the last segments that could possibly have generic
+            // arguments
+            left = left_seg;
+            right = right_seg;
+        }
+
+        over(left, right, |l, r| self.eq_path_segment(l, r))
     }
 
     pub fn eq_path_segment(&mut self, left: &PathSegment<'_>, right: &PathSegment<'_>) -> bool {
-        // The == of idents doesn't work with different contexts,
-        // we have to be explicit about hygiene
-        left.ident.name == right.ident.name
-            && both(left.args.as_ref(), right.args.as_ref(), |l, r| {
-                self.eq_path_parameters(l, r)
-            })
+        if !self.eq_path_parameters(left.args(), right.args()) {
+            return false;
+        }
+
+        if let PathCheck::Resolution = self.inner.path_check
+            && left.res != Res::Err
+            && right.res != Res::Err
+        {
+            left.res == right.res
+        } else {
+            // The == of idents doesn't work with different contexts,
+            // we have to be explicit about hygiene
+            left.ident.name == right.ident.name
+        }
     }
 
     pub fn eq_ty(&mut self, left: &Ty<'_>, right: &Ty<'_>) -> bool {
@@ -684,6 +740,21 @@ pub fn eq_expr_value(cx: &LateContext<'_>, left: &Expr<'_>, right: &Expr<'_>) ->
     SpanlessEq::new(cx).deny_side_effects().eq_expr(left, right)
 }
 
+/// Returns the segments of a path that might have generic parameters.
+/// Usually just the last segment for free items, except for when the path resolves to an associated
+/// item, in which case it is the last two
+fn generic_path_segments<'tcx>(segments: &'tcx [PathSegment<'tcx>]) -> Option<&'tcx [PathSegment<'tcx>]> {
+    match segments.last()?.res {
+        Res::Def(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy, _) => {
+            // <Ty as module::Trait<T>>::assoc::<U>
+            //        ^^^^^^^^^^^^^^^^   ^^^^^^^^^^ segments: [module, Trait<T>, assoc<U>]
+            Some(&segments[segments.len().checked_sub(2)?..])
+        },
+        Res::Err => None,
+        _ => Some(slice::from_ref(segments.last()?)),
+    }
+}
+
 /// Type used to hash an ast element. This is different from the `Hash` trait
 /// on ast types as this
 /// trait would consider IDs and spans.
@@ -694,6 +765,7 @@ pub struct SpanlessHash<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     maybe_typeck_results: Option<&'tcx TypeckResults<'tcx>>,
     s: FxHasher,
+    path_check: PathCheck,
 }
 
 impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
@@ -701,10 +773,21 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
         Self {
             cx,
             maybe_typeck_results: cx.maybe_typeck_results(),
+            path_check: PathCheck::default(),
             s: FxHasher::default(),
         }
     }
 
+    /// Check paths by their resolution instead of exact equality. See [`PathCheck`] for more
+    /// details.
+    #[must_use]
+    pub fn paths_by_resolution(self) -> Self {
+        Self {
+            path_check: PathCheck::Resolution,
+            ..self
+        }
+    }
+
     pub fn finish(self) -> u64 {
         self.s.finish()
     }
@@ -1042,9 +1125,19 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
             // even though the binding names are different and they have different `HirId`s.
             Res::Local(_) => 1_usize.hash(&mut self.s),
             _ => {
-                for seg in path.segments {
-                    self.hash_name(seg.ident.name);
-                    self.hash_generic_args(seg.args().args);
+                if let PathCheck::Resolution = self.path_check
+                    && let [.., last] = path.segments
+                    && let Some(segments) = generic_path_segments(path.segments)
+                {
+                    for seg in segments {
+                        self.hash_generic_args(seg.args().args);
+                    }
+                    last.res.hash(&mut self.s);
+                } else {
+                    for seg in path.segments {
+                        self.hash_name(seg.ident.name);
+                        self.hash_generic_args(seg.args().args);
+                    }
                 }
             },
         }

clippy_utils/src/lib.rs

@@ -3,6 +3,7 @@
 #![feature(f128)]
 #![feature(f16)]
 #![feature(if_let_guard)]
+#![feature(macro_metavar_expr_concat)]
 #![feature(let_chains)]
 #![feature(never_type)]
 #![feature(rustc_private)]
@@ -128,7 +129,6 @@ use crate::consts::{ConstEvalCtxt, Constant, mir_to_const};
 use crate::higher::Range;
 use crate::ty::{adt_and_variant_of_res, can_partially_move_ty, expr_sig, is_copy, is_recursively_primitive_type};
 use crate::visitors::for_each_expr_without_closures;
-
 use rustc_middle::hir::nested_filter;
 
 #[macro_export]

clippy_utils/src/ty.rs

@@ -1168,7 +1168,7 @@ pub fn make_normalized_projection<'tcx>(
 pub struct InteriorMut<'tcx> {
     ignored_def_ids: FxHashSet<DefId>,
     ignore_pointers: bool,
-    tys: FxHashMap<Ty<'tcx>, Option<bool>>,
+    tys: FxHashMap<Ty<'tcx>, Option<&'tcx ty::List<Ty<'tcx>>>>,
 }
 
 impl<'tcx> InteriorMut<'tcx> {
@@ -1194,25 +1194,24 @@ impl<'tcx> InteriorMut<'tcx> {
         }
     }
 
-    /// Check if given type has inner mutability such as [`std::cell::Cell`] or
-    /// [`std::cell::RefCell`] etc.
-    pub fn is_interior_mut_ty(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
+    /// Check if given type has interior mutability such as [`std::cell::Cell`] or
+    /// [`std::cell::RefCell`] etc. and if it does, returns a chain of types that causes
+    /// this type to be interior mutable
+    pub fn interior_mut_ty_chain(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<&'tcx ty::List<Ty<'tcx>>> {
         match self.tys.entry(ty) {
-            Entry::Occupied(o) => return *o.get() == Some(true),
+            Entry::Occupied(o) => return *o.get(),
             // Temporarily insert a `None` to break cycles
             Entry::Vacant(v) => v.insert(None),
         };
 
-        let interior_mut = match *ty.kind() {
-            ty::RawPtr(inner_ty, _) if !self.ignore_pointers => self.is_interior_mut_ty(cx, inner_ty),
-            ty::Ref(_, inner_ty, _) | ty::Slice(inner_ty) => self.is_interior_mut_ty(cx, inner_ty),
-            ty::Array(inner_ty, size) => {
-                size.try_eval_target_usize(cx.tcx, cx.param_env)
-                    .map_or(true, |u| u != 0)
-                    && self.is_interior_mut_ty(cx, inner_ty)
+        let chain = match *ty.kind() {
+            ty::RawPtr(inner_ty, _) if !self.ignore_pointers => self.interior_mut_ty_chain(cx, inner_ty),
+            ty::Ref(_, inner_ty, _) | ty::Slice(inner_ty) => self.interior_mut_ty_chain(cx, inner_ty),
+            ty::Array(inner_ty, size) if size.try_eval_target_usize(cx.tcx, cx.param_env) != Some(0) => {
+                self.interior_mut_ty_chain(cx, inner_ty)
             },
-            ty::Tuple(fields) => fields.iter().any(|ty| self.is_interior_mut_ty(cx, ty)),
-            ty::Adt(def, _) if def.is_unsafe_cell() => true,
+            ty::Tuple(fields) => fields.iter().find_map(|ty| self.interior_mut_ty_chain(cx, ty)),
+            ty::Adt(def, _) if def.is_unsafe_cell() => Some(ty::List::empty()),
             ty::Adt(def, args) => {
                 let is_std_collection = matches!(
                     cx.tcx.get_diagnostic_name(def.did()),
@@ -1231,19 +1230,28 @@ impl<'tcx> InteriorMut<'tcx> {
 
                 if is_std_collection || def.is_box() {
                     // Include the types from std collections that are behind pointers internally
-                    args.types().any(|ty| self.is_interior_mut_ty(cx, ty))
+                    args.types().find_map(|ty| self.interior_mut_ty_chain(cx, ty))
                 } else if self.ignored_def_ids.contains(&def.did()) || def.is_phantom_data() {
-                    false
+                    None
                 } else {
                     def.all_fields()
-                        .any(|f| self.is_interior_mut_ty(cx, f.ty(cx.tcx, args)))
+                        .find_map(|f| self.interior_mut_ty_chain(cx, f.ty(cx.tcx, args)))
                 }
             },
-            _ => false,
+            _ => None,
         };
 
-        self.tys.insert(ty, Some(interior_mut));
-        interior_mut
+        chain.map(|chain| {
+            let list = cx.tcx.mk_type_list_from_iter(chain.iter().chain([ty]));
+            self.tys.insert(ty, Some(list));
+            list
+        })
+    }
+
+    /// Check if given type has interior mutability such as [`std::cell::Cell`] or
+    /// [`std::cell::RefCell`] etc.
+    pub fn is_interior_mut_ty(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
+        self.interior_mut_ty_chain(cx, ty).is_some()
     }
 }