Auto merge of #120466 - Dylan-DPC:rollup-v0or19a, r=Dylan-DPC

Rollup of 9 pull requests

Successful merges:

 - #116677 (References refer to allocated objects)
 - #118625 (Improve handling of expressions in patterns)
 - #120266 (Improve documentation for [A]Rc::into_inner)
 - #120373 (Adjust Behaviour of `read_dir` and `ReadDir` in Windows Implementation: Check Whether Path to Search In Exists)
 - #120390 (Borrow check inline const patterns)
 - #120420 (Stop using derivative in rustc_pattern_analysis)
 - #120428 (hir: Two preparatory changes for #120206)
 - #120453 (Fix incorrect comment in normalize_newlines)
 - #120462 (Clean dead code)

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

Cargo.lock

@@ -4342,7 +4342,6 @@ dependencies = [
 name = "rustc_pattern_analysis"
 version = "0.0.0"
 dependencies = [
- "derivative",
  "rustc-hash",
  "rustc_apfloat",
  "rustc_arena",

compiler/rustc_ast_lowering/src/expr.rs

@@ -153,7 +153,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::Let(pat, scrutinee, span, is_recovered) => {
                     hir::ExprKind::Let(self.arena.alloc(hir::Let {
-                        hir_id: self.next_id(),
                         span: self.lower_span(*span),
                         pat: self.lower_pat(pat),
                         ty: None,

compiler/rustc_ast_lowering/src/lib.rs

@@ -2305,7 +2305,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         match c.value.kind {
             ExprKind::Underscore => {
                 if self.tcx.features().generic_arg_infer {
-                    hir::ArrayLen::Infer(self.lower_node_id(c.id), self.lower_span(c.value.span))
+                    hir::ArrayLen::Infer(hir::InferArg {
+                        hir_id: self.lower_node_id(c.id),
+                        span: self.lower_span(c.value.span),
+                    })
                 } else {
                     feature_err(
                         &self.tcx.sess,

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1099,10 +1099,17 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     #[instrument(skip(self), level = "debug")]
     fn check_user_type_annotations(&mut self) {
         debug!(?self.user_type_annotations);
+        let tcx = self.tcx();
         for user_annotation in self.user_type_annotations {
             let CanonicalUserTypeAnnotation { span, ref user_ty, inferred_ty } = *user_annotation;
             let annotation = self.instantiate_canonical_with_fresh_inference_vars(span, user_ty);
-            self.ascribe_user_type(inferred_ty, annotation, span);
+            if let ty::UserType::TypeOf(def, args) = annotation
+                && let DefKind::InlineConst = tcx.def_kind(def)
+            {
+                self.check_inline_const(inferred_ty, def.expect_local(), args, span);
+            } else {
+                self.ascribe_user_type(inferred_ty, annotation, span);
+            }
         }
     }
 
@@ -1195,6 +1202,36 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         Ok(())
     }
 
+    fn check_inline_const(
+        &mut self,
+        inferred_ty: Ty<'tcx>,
+        def_id: LocalDefId,
+        args: UserArgs<'tcx>,
+        span: Span,
+    ) {
+        assert!(args.user_self_ty.is_none());
+        let tcx = self.tcx();
+        let const_ty = tcx.type_of(def_id).instantiate(tcx, args.args);
+        if let Err(terr) =
+            self.eq_types(const_ty, inferred_ty, Locations::All(span), ConstraintCategory::Boring)
+        {
+            span_bug!(
+                span,
+                "bad inline const pattern: ({:?} = {:?}) {:?}",
+                const_ty,
+                inferred_ty,
+                terr
+            );
+        }
+        let args = self.infcx.resolve_vars_if_possible(args.args);
+        let predicates = self.prove_closure_bounds(tcx, def_id, args, Locations::All(span));
+        self.normalize_and_prove_instantiated_predicates(
+            def_id.to_def_id(),
+            predicates,
+            Locations::All(span),
+        );
+    }
+
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.infcx.tcx
     }
@@ -1851,7 +1888,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     let def_id = uv.def;
                     if tcx.def_kind(def_id) == DefKind::InlineConst {
                         let def_id = def_id.expect_local();
-                        let predicates = self.prove_closure_bounds(tcx, def_id, uv.args, location);
+                        let predicates = self.prove_closure_bounds(
+                            tcx,
+                            def_id,
+                            uv.args,
+                            location.to_locations(),
+                        );
                         self.normalize_and_prove_instantiated_predicates(
                             def_id.to_def_id(),
                             predicates,
@@ -2654,9 +2696,15 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             // desugaring. A closure gets desugared to a struct, and
             // these extra requirements are basically like where
             // clauses on the struct.
-            AggregateKind::Closure(def_id, args) | AggregateKind::Coroutine(def_id, args) => {
-                (def_id, self.prove_closure_bounds(tcx, def_id.expect_local(), args, location))
-            }
+            AggregateKind::Closure(def_id, args) | AggregateKind::Coroutine(def_id, args) => (
+                def_id,
+                self.prove_closure_bounds(
+                    tcx,
+                    def_id.expect_local(),
+                    args,
+                    location.to_locations(),
+                ),
+            ),
 
             AggregateKind::Array(_) | AggregateKind::Tuple => {
                 (CRATE_DEF_ID.to_def_id(), ty::InstantiatedPredicates::empty())
@@ -2675,7 +2723,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         tcx: TyCtxt<'tcx>,
         def_id: LocalDefId,
         args: GenericArgsRef<'tcx>,
-        location: Location,
+        locations: Locations,
     ) -> ty::InstantiatedPredicates<'tcx> {
         if let Some(closure_requirements) = &tcx.mir_borrowck(def_id).closure_requirements {
             constraint_conversion::ConstraintConversion::new(
@@ -2684,7 +2732,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 self.region_bound_pairs,
                 self.implicit_region_bound,
                 self.param_env,
-                location.to_locations(),
+                locations,
                 DUMMY_SP,                   // irrelevant; will be overridden.
                 ConstraintCategory::Boring, // same as above.
                 self.borrowck_context.constraints,
@@ -2710,7 +2758,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         if let Err(_) = self.eq_args(
             typeck_root_args,
             parent_args,
-            location.to_locations(),
+            locations,
             ConstraintCategory::BoringNoLocation,
         ) {
             span_mirbug!(

compiler/rustc_hir/src/hir.rs

@@ -1273,7 +1273,6 @@ pub struct Arm<'hir> {
 /// desugaring to if-let. Only let-else supports the type annotation at present.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub struct Let<'hir> {
-    pub hir_id: HirId,
     pub span: Span,
     pub pat: &'hir Pat<'hir>,
     pub ty: Option<&'hir Ty<'hir>>,
@@ -1532,14 +1531,16 @@ pub type Lit = Spanned<LitKind>;
 
 #[derive(Copy, Clone, Debug, HashStable_Generic)]
 pub enum ArrayLen {
-    Infer(HirId, Span),
+    Infer(InferArg),
     Body(AnonConst),
 }
 
 impl ArrayLen {
     pub fn hir_id(&self) -> HirId {
         match self {
-            &ArrayLen::Infer(hir_id, _) | &ArrayLen::Body(AnonConst { hir_id, .. }) => hir_id,
+            ArrayLen::Infer(InferArg { hir_id, .. }) | ArrayLen::Body(AnonConst { hir_id, .. }) => {
+                *hir_id
+            }
         }
     }
 }
@@ -2424,7 +2425,7 @@ impl<'hir> Ty<'hir> {
             TyKind::Infer => true,
             TyKind::Slice(ty) => ty.is_suggestable_infer_ty(),
             TyKind::Array(ty, length) => {
-                ty.is_suggestable_infer_ty() || matches!(length, ArrayLen::Infer(_, _))
+                ty.is_suggestable_infer_ty() || matches!(length, ArrayLen::Infer(..))
             }
             TyKind::Tup(tys) => tys.iter().any(Self::is_suggestable_infer_ty),
             TyKind::Ptr(mut_ty) | TyKind::Ref(_, mut_ty) => mut_ty.ty.is_suggestable_infer_ty(),

compiler/rustc_hir/src/intravisit.rs

@@ -341,9 +341,6 @@ pub trait Visitor<'v>: Sized {
     fn visit_expr(&mut self, ex: &'v Expr<'v>) {
         walk_expr(self, ex)
     }
-    fn visit_let_expr(&mut self, lex: &'v Let<'v>) {
-        walk_let_expr(self, lex)
-    }
     fn visit_expr_field(&mut self, field: &'v ExprField<'v>) {
         walk_expr_field(self, field)
     }
@@ -672,7 +669,7 @@ pub fn walk_pat_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v PatField<'
 
 pub fn walk_array_len<'v, V: Visitor<'v>>(visitor: &mut V, len: &'v ArrayLen) {
     match len {
-        &ArrayLen::Infer(hir_id, _span) => visitor.visit_id(hir_id),
+        ArrayLen::Infer(InferArg { hir_id, span: _ }) => visitor.visit_id(*hir_id),
         ArrayLen::Body(c) => visitor.visit_anon_const(c),
     }
 }
@@ -729,7 +726,12 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
         ExprKind::DropTemps(ref subexpression) => {
             visitor.visit_expr(subexpression);
         }
-        ExprKind::Let(ref let_expr) => visitor.visit_let_expr(let_expr),
+        ExprKind::Let(Let { span: _, pat, ty, init, is_recovered: _ }) => {
+            // match the visit order in walk_local
+            visitor.visit_expr(init);
+            visitor.visit_pat(pat);
+            walk_list!(visitor, visit_ty, ty);
+        }
         ExprKind::If(ref cond, ref then, ref else_opt) => {
             visitor.visit_expr(cond);
             visitor.visit_expr(then);
@@ -806,14 +808,6 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
     }
 }
 
-pub fn walk_let_expr<'v, V: Visitor<'v>>(visitor: &mut V, let_expr: &'v Let<'v>) {
-    // match the visit order in walk_local
-    visitor.visit_expr(let_expr.init);
-    visitor.visit_id(let_expr.hir_id);
-    visitor.visit_pat(let_expr.pat);
-    walk_list!(visitor, visit_ty, let_expr.ty);
-}
-
 pub fn walk_expr_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v ExprField<'v>) {
     visitor.visit_id(field.hir_id);
     visitor.visit_ident(field.ident);

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2529,7 +2529,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             }
             hir::TyKind::Array(ty, length) => {
                 let length = match length {
-                    &hir::ArrayLen::Infer(_, span) => self.ct_infer(tcx.types.usize, None, span),
+                    hir::ArrayLen::Infer(inf) => self.ct_infer(tcx.types.usize, None, inf.span),
                     hir::ArrayLen::Body(constant) => {
                         ty::Const::from_anon_const(tcx, constant.def_id)
                     }

compiler/rustc_hir_analysis/src/collect.rs

@@ -146,8 +146,8 @@ impl<'v> Visitor<'v> for HirPlaceholderCollector {
         }
     }
     fn visit_array_length(&mut self, length: &'v hir::ArrayLen) {
-        if let &hir::ArrayLen::Infer(_, span) = length {
-            self.0.push(span);
+        if let hir::ArrayLen::Infer(inf) = length {
+            self.0.push(inf.span);
         }
         intravisit::walk_array_len(self, length)
     }

compiler/rustc_hir_pretty/src/lib.rs

@@ -956,7 +956,7 @@ impl<'a> State<'a> {
 
     fn print_array_length(&mut self, len: &hir::ArrayLen) {
         match len {
-            hir::ArrayLen::Infer(_, _) => self.word("_"),
+            hir::ArrayLen::Infer(..) => self.word("_"),
             hir::ArrayLen::Body(ct) => self.print_anon_const(ct),
         }
     }

compiler/rustc_hir_typeck/src/expr.rs

@@ -320,7 +320,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             ExprKind::Ret(ref expr_opt) => self.check_expr_return(expr_opt.as_deref(), expr),
             ExprKind::Become(call) => self.check_expr_become(call, expr),
-            ExprKind::Let(let_expr) => self.check_expr_let(let_expr),
+            ExprKind::Let(let_expr) => self.check_expr_let(let_expr, expr.hir_id),
             ExprKind::Loop(body, _, source, _) => {
                 self.check_expr_loop(body, source, expected, expr)
             }
@@ -1259,12 +1259,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub(super) fn check_expr_let(&self, let_expr: &'tcx hir::Let<'tcx>) -> Ty<'tcx> {
+    pub(super) fn check_expr_let(&self, let_expr: &'tcx hir::Let<'tcx>, hir_id: HirId) -> Ty<'tcx> {
         // for let statements, this is done in check_stmt
         let init = let_expr.init;
         self.warn_if_unreachable(init.hir_id, init.span, "block in `let` expression");
         // otherwise check exactly as a let statement
-        self.check_decl(let_expr.into());
+        self.check_decl((let_expr, hir_id).into());
         // but return a bool, for this is a boolean expression
         if let Some(error_guaranteed) = let_expr.is_recovered {
             self.set_tainted_by_errors(error_guaranteed);

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -405,7 +405,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     pub fn array_length_to_const(&self, length: &hir::ArrayLen) -> ty::Const<'tcx> {
         match length {
-            &hir::ArrayLen::Infer(_, span) => self.ct_infer(self.tcx.types.usize, None, span),
+            hir::ArrayLen::Infer(inf) => self.ct_infer(self.tcx.types.usize, None, inf.span),
             hir::ArrayLen::Body(anon_const) => {
                 let span = self.tcx.def_span(anon_const.def_id);
                 let c = ty::Const::from_anon_const(self.tcx, anon_const.def_id);

compiler/rustc_hir_typeck/src/gather_locals.rs

@@ -48,9 +48,9 @@ impl<'a> From<&'a hir::Local<'a>> for Declaration<'a> {
     }
 }
 
-impl<'a> From<&'a hir::Let<'a>> for Declaration<'a> {
-    fn from(let_expr: &'a hir::Let<'a>) -> Self {
-        let hir::Let { hir_id, pat, ty, span, init, is_recovered: _ } = *let_expr;
+impl<'a> From<(&'a hir::Let<'a>, hir::HirId)> for Declaration<'a> {
+    fn from((let_expr, hir_id): (&'a hir::Let<'a>, hir::HirId)) -> Self {
+        let hir::Let { pat, ty, span, init, is_recovered: _ } = *let_expr;
         Declaration { hir_id, pat, ty, span, init: Some(init), origin: DeclOrigin::LetExpr }
     }
 }
@@ -125,9 +125,11 @@ impl<'a, 'tcx> Visitor<'tcx> for GatherLocalsVisitor<'a, 'tcx> {
         intravisit::walk_local(self, local)
     }
 
-    fn visit_let_expr(&mut self, let_expr: &'tcx hir::Let<'tcx>) {
-        self.declare(let_expr.into());
-        intravisit::walk_let_expr(self, let_expr);
+    fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
+        if let hir::ExprKind::Let(let_expr) = expr.kind {
+            self.declare((let_expr, expr.hir_id).into());
+        }
+        intravisit::walk_expr(self, expr)
     }
 
     fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {

compiler/rustc_mir_build/src/build/matches/simplify.rs

@@ -15,7 +15,9 @@
 use crate::build::expr::as_place::PlaceBuilder;
 use crate::build::matches::{Ascription, Binding, Candidate, MatchPair};
 use crate::build::Builder;
+use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_middle::thir::{self, *};
+use rustc_middle::ty;
 
 use std::mem;
 
@@ -149,7 +151,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 ref subpattern,
                 ascription: thir::Ascription { ref annotation, variance },
             } => {
-                // Apply the type ascription to the value at `match_pair.place`, which is the
+                // Apply the type ascription to the value at `match_pair.place`
                 if let Some(source) = match_pair.place.try_to_place(self) {
                     candidate.ascriptions.push(Ascription {
                         annotation: annotation.clone(),
@@ -205,7 +207,38 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Err(match_pair)
             }
 
-            PatKind::InlineConstant { subpattern: ref pattern, def: _ } => {
+            PatKind::InlineConstant { subpattern: ref pattern, def } => {
+                // Apply a type ascription for the inline constant to the value at `match_pair.place`
+                if let Some(source) = match_pair.place.try_to_place(self) {
+                    let span = match_pair.pattern.span;
+                    let parent_id = self.tcx.typeck_root_def_id(self.def_id.to_def_id());
+                    let args = ty::InlineConstArgs::new(
+                        self.tcx,
+                        ty::InlineConstArgsParts {
+                            parent_args: ty::GenericArgs::identity_for_item(self.tcx, parent_id),
+                            ty: self.infcx.next_ty_var(TypeVariableOrigin {
+                                kind: TypeVariableOriginKind::MiscVariable,
+                                span,
+                            }),
+                        },
+                    )
+                    .args;
+                    let user_ty =
+                        self.infcx.canonicalize_user_type_annotation(ty::UserType::TypeOf(
+                            def.to_def_id(),
+                            ty::UserArgs { args, user_self_ty: None },
+                        ));
+                    let annotation = ty::CanonicalUserTypeAnnotation {
+                        inferred_ty: pattern.ty,
+                        span,
+                        user_ty: Box::new(user_ty),
+                    };
+                    candidate.ascriptions.push(Ascription {
+                        annotation,
+                        source,
+                        variance: ty::Contravariant,
+                    });
+                }
                 candidate.match_pairs.push(MatchPair::new(match_pair.place, pattern, self));
 
                 Ok(())

compiler/rustc_parse/messages.ftl

@@ -772,6 +772,20 @@ parse_unexpected_const_param_declaration = unexpected `const` parameter declarat
 parse_unexpected_default_value_for_lifetime_in_generic_parameters = unexpected default lifetime parameter
     .label = lifetime parameters cannot have default values
 
+parse_unexpected_expr_in_pat =
+    expected {$is_bound ->
+        [true] a pattern range bound
+       *[false] a pattern
+    }, found {$is_method_call ->
+        [true] a method call
+       *[false] an expression
+    }
+
+    .label = {$is_method_call ->
+        [true] method calls
+       *[false] arbitrary expressions
+    } are not allowed in patterns
+
 parse_unexpected_if_with_if = unexpected `if` in the condition expression
     .suggestion = remove the `if`