Auto merge of rust-lang#82153 - jonas-schievink:rollup-ls5r943, r=jonas-schievink

Rollup of 19 pull requests

Successful merges:

 - rust-lang#81503 (Suggest to create a new `const` item if the `fn` in the array is a `const fn`)
 - rust-lang#81897 (Add match pattern diagnostics regression test)
 - rust-lang#81975 (Seal the CommandExt, OsStrExt and OsStringExt traits)
 - rust-lang#82009 (const_generics: Dont evaluate array length const when handling errors)
 - rust-lang#82060 (Fix typos in BTreeSet::{first, last} docs)
 - rust-lang#82061 (CTFE validation: catch ReadPointerAsBytes and better error)
 - rust-lang#82063 (Fixed minor typo in catch_unwind docs)
 - rust-lang#82067 (const_generics: Fix incorrect ty::ParamEnv::empty() usage)
 - rust-lang#82077 (Edit `rustc_arena::DropArena` docs)
 - rust-lang#82096 (Fix a typo)
 - rust-lang#82106 (Remove unnecessary `Option` in `default_doc`)
 - rust-lang#82107 (expand: Some cleanup)
 - rust-lang#82118 (Add missing env!-decl variant)
 - rust-lang#82119 (Fix typo in link to CreateSymbolicLinkW documentation.)
 - rust-lang#82120 (Stabilize Arguments::as_str)
 - rust-lang#82129 (Remove redundant bool_to_option feature gate)
 - rust-lang#82133 (Update link for extern prelude.)
 - rust-lang#82141 (32-bit ARM: Emit `lr` instead of `r14` when specified as an `asm!` output register.)
 - rust-lang#82147 (:arrow_up: rust-analyzer)

Failed merges:

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

Author: bors

compiler/rustc_arena/src/lib.rs

@@ -568,10 +568,13 @@ impl Drop for DropType {
 }
 
 /// An arena which can be used to allocate any type.
+///
+/// # Safety
+///
 /// Allocating in this arena is unsafe since the type system
 /// doesn't know which types it contains. In order to
-/// allocate safely, you must store a PhantomData<T>
-/// alongside this arena for each type T you allocate.
+/// allocate safely, you must store a `PhantomData<T>`
+/// alongside this arena for each type `T` you allocate.
 #[derive(Default)]
 pub struct DropArena {
     /// A list of destructors to run when the arena drops.
@@ -589,7 +592,7 @@ impl DropArena {
         ptr::write(mem, object);
         let result = &mut *mem;
         // Record the destructor after doing the allocation as that may panic
-        // and would cause `object`'s destructor to run twice if it was recorded before
+        // and would cause `object`'s destructor to run twice if it was recorded before.
         self.destructors
             .borrow_mut()
             .push(DropType { drop_fn: drop_for_type::<T>, obj: result as *mut T as *mut u8 });
@@ -607,16 +610,16 @@ impl DropArena {
         let start_ptr = self.arena.alloc_raw(Layout::array::<T>(len).unwrap()) as *mut T;
 
         let mut destructors = self.destructors.borrow_mut();
-        // Reserve space for the destructors so we can't panic while adding them
+        // Reserve space for the destructors so we can't panic while adding them.
         destructors.reserve(len);
 
         // Move the content to the arena by copying it and then forgetting
-        // the content of the SmallVec
+        // the content of the SmallVec.
         vec.as_ptr().copy_to_nonoverlapping(start_ptr, len);
         mem::forget(vec.drain(..));
 
         // Record the destructors after doing the allocation as that may panic
-        // and would cause `object`'s destructor to run twice if it was recorded before
+        // and would cause `object`'s destructor to run twice if it was recorded before.
         for i in 0..len {
             destructors
                 .push(DropType { drop_fn: drop_for_type::<T>, obj: start_ptr.add(i) as *mut u8 });

compiler/rustc_codegen_llvm/src/asm.rs

@@ -487,6 +487,9 @@ fn reg_to_llvm(reg: InlineAsmRegOrRegClass, layout: Option<&TyAndLayout<'tcx>>)
             } else if reg == InlineAsmReg::AArch64(AArch64InlineAsmReg::x30) {
                 // LLVM doesn't recognize x30
                 "{lr}".to_string()
+            } else if reg == InlineAsmReg::Arm(ArmInlineAsmReg::r14) {
+                // LLVM doesn't recognize r14
+                "{lr}".to_string()
             } else {
                 format!("{{{}}}", reg.name())
             }

compiler/rustc_expand/src/expand.rs

@@ -1067,8 +1067,6 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
     fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
         self.cfg.configure_expr(expr);
         visit_clobber(expr.deref_mut(), |mut expr| {
-            self.cfg.configure_expr_kind(&mut expr.kind);
-
             if let Some(attr) = self.take_first_attr(&mut expr) {
                 // Collect the invoc regardless of whether or not attributes are permitted here
                 // expansion will eat the attribute so it won't error later.
@@ -1166,8 +1164,6 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
     fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
         let expr = configure!(self, expr);
         expr.filter_map(|mut expr| {
-            self.cfg.configure_expr_kind(&mut expr.kind);
-
             if let Some(attr) = self.take_first_attr(&mut expr) {
                 self.cfg.maybe_emit_expr_attr_err(&attr.0);
 
@@ -1192,7 +1188,6 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
     }
 
     fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
-        self.cfg.configure_pat(pat);
         match pat.kind {
             PatKind::MacCall(_) => {}
             _ => return noop_visit_pat(pat, self),
@@ -1406,15 +1401,12 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
         });
     }
 
-    fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
-        self.cfg.configure_foreign_mod(foreign_mod);
-        noop_visit_foreign_mod(foreign_mod, self);
-    }
-
     fn flat_map_foreign_item(
         &mut self,
-        mut foreign_item: P<ast::ForeignItem>,
+        foreign_item: P<ast::ForeignItem>,
     ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
+        let mut foreign_item = configure!(self, foreign_item);
+
         if let Some(attr) = self.take_first_attr(&mut foreign_item) {
             return self
                 .collect_attr(
@@ -1439,11 +1431,6 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
         }
     }
 
-    fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
-        self.cfg.configure_item_kind(item);
-        noop_visit_item_kind(item, self);
-    }
-
     fn flat_map_generic_param(
         &mut self,
         param: ast::GenericParam,
@@ -1602,21 +1589,15 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
             *id = self.cx.resolver.next_node_id()
         }
     }
-
-    fn visit_fn_decl(&mut self, mut fn_decl: &mut P<ast::FnDecl>) {
-        self.cfg.configure_fn_decl(&mut fn_decl);
-        noop_visit_fn_decl(fn_decl, self);
-    }
 }
 
 pub struct ExpansionConfig<'feat> {
     pub crate_name: String,
     pub features: Option<&'feat Features>,
     pub recursion_limit: Limit,
     pub trace_mac: bool,
-    pub should_test: bool, // If false, strip `#[test]` nodes
-    pub keep_macs: bool,
-    pub span_debug: bool, // If true, use verbose debugging for `proc_macro::Span`
+    pub should_test: bool,          // If false, strip `#[test]` nodes
+    pub span_debug: bool,           // If true, use verbose debugging for `proc_macro::Span`
     pub proc_macro_backtrace: bool, // If true, show backtraces for proc-macro panics
 }
 
@@ -1628,7 +1609,6 @@ impl<'feat> ExpansionConfig<'feat> {
             recursion_limit: Limit::new(1024),
             trace_mac: false,
             should_test: false,
-            keep_macs: false,
             span_debug: false,
             proc_macro_backtrace: false,
         }

compiler/rustc_expand/src/lib.rs

@@ -1,4 +1,3 @@
-#![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(or_patterns)]

compiler/rustc_expand/src/placeholders.rs

@@ -371,12 +371,4 @@ impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
             }
         }
     }
-
-    fn visit_mod(&mut self, module: &mut ast::Mod) {
-        noop_visit_mod(module, self);
-        // remove macro definitions
-        module.items.retain(
-            |item| !matches!(item.kind, ast::ItemKind::MacCall(_) if !self.cx.ecfg.keep_macs),
-        );
-    }
 }

compiler/rustc_infer/src/infer/canonical/query_response.rs

@@ -639,6 +639,10 @@ struct QueryTypeRelatingDelegate<'a, 'tcx> {
 }
 
 impl<'tcx> TypeRelatingDelegate<'tcx> for QueryTypeRelatingDelegate<'_, 'tcx> {
+    fn param_env(&self) -> ty::ParamEnv<'tcx> {
+        self.param_env
+    }
+
     fn create_next_universe(&mut self) -> ty::UniverseIndex {
         self.infcx.create_next_universe()
     }

compiler/rustc_infer/src/infer/combine.rs

@@ -221,6 +221,7 @@ impl<'infcx, 'tcx> InferCtxt<'infcx, 'tcx> {
     /// As `3 + 4` contains `N` in its substs, this must not succeed.
     ///
     /// See `src/test/ui/const-generics/occurs-check/` for more examples where this is relevant.
+    #[instrument(level = "debug", skip(self))]
     fn unify_const_variable(
         &self,
         param_env: ty::ParamEnv<'tcx>,

compiler/rustc_infer/src/infer/nll_relate/mod.rs

@@ -72,6 +72,8 @@ where
 }
 
 pub trait TypeRelatingDelegate<'tcx> {
+    fn param_env(&self) -> ty::ParamEnv<'tcx>;
+
     /// Push a constraint `sup: sub` -- this constraint must be
     /// satisfied for the two types to be related. `sub` and `sup` may
     /// be regions from the type or new variables created through the
@@ -473,9 +475,8 @@ where
         self.infcx.tcx
     }
 
-    // FIXME(oli-obk): not sure how to get the correct ParamEnv
     fn param_env(&self) -> ty::ParamEnv<'tcx> {
-        ty::ParamEnv::empty()
+        self.delegate.param_env()
     }
 
     fn tag(&self) -> &'static str {
@@ -819,9 +820,8 @@ where
         self.infcx.tcx
     }
 
-    // FIXME(oli-obk): not sure how to get the correct ParamEnv
     fn param_env(&self) -> ty::ParamEnv<'tcx> {
-        ty::ParamEnv::empty()
+        self.delegate.param_env()
     }
 
     fn tag(&self) -> &'static str {

compiler/rustc_middle/src/mir/interpret/queries.rs

@@ -31,6 +31,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// constant `bar::<T>()` requires a substitution for `T`, if the substitution for `T` is still
     /// too generic for the constant to be evaluated then `Err(ErrorHandled::TooGeneric)` is
     /// returned.
+    #[instrument(level = "debug", skip(self))]
     pub fn const_eval_resolve(
         self,
         param_env: ty::ParamEnv<'tcx>,

compiler/rustc_middle/src/traits/mod.rs

@@ -228,7 +228,10 @@ pub enum ObligationCauseCode<'tcx> {
     /// Inline asm operand type must be `Sized`.
     InlineAsmSized,
     /// `[T, ..n]` implies that `T` must be `Copy`.
-    RepeatVec,
+    /// If the function in the array repeat expression is a `const fn`,
+    /// display a help message suggesting to move the function call to a
+    /// new `const` item while saying that `T` doesn't implement `Copy`.
+    RepeatVec(bool),
 
     /// Types of fields (other than the last, except for packed structs) in a struct must be sized.
     FieldSized {

compiler/rustc_middle/src/ty/error.rs

@@ -228,12 +228,17 @@ impl<'tcx> ty::TyS<'tcx> {
             ty::Adt(def, _) => format!("{} `{}`", def.descr(), tcx.def_path_str(def.did)).into(),
             ty::Foreign(def_id) => format!("extern type `{}`", tcx.def_path_str(def_id)).into(),
             ty::Array(t, n) => {
+                if t.is_simple_ty() {
+                    return format!("array `{}`", self).into();
+                }
+
                 let n = tcx.lift(n).unwrap();
-                match n.try_eval_usize(tcx, ty::ParamEnv::empty()) {
-                    _ if t.is_simple_ty() => format!("array `{}`", self).into(),
-                    Some(n) => format!("array of {} element{}", n, pluralize!(n)).into(),
-                    None => "array".into(),
+                if let ty::ConstKind::Value(v) = n.val {
+                    if let Some(n) = v.try_to_machine_usize(tcx) {
+                        return format!("array of {} element{}", n, pluralize!(n)).into();
+                    }
                 }
+                "array".into()
             }
             ty::Slice(ty) if ty.is_simple_ty() => format!("slice `{}`", self).into(),
             ty::Slice(_) => "slice".into(),

compiler/rustc_middle/src/ty/instance.rs

@@ -347,6 +347,7 @@ impl<'tcx> Instance<'tcx> {
     }
 
     // This should be kept up to date with `resolve`.
+    #[instrument(level = "debug", skip(tcx))]
     pub fn resolve_opt_const_arg(
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,

compiler/rustc_mir/src/borrow_check/type_check/mod.rs

@@ -43,6 +43,9 @@ use rustc_trait_selection::traits::{self, ObligationCause, PredicateObligations}
 use crate::dataflow::impls::MaybeInitializedPlaces;
 use crate::dataflow::move_paths::MoveData;
 use crate::dataflow::ResultsCursor;
+use crate::transform::{
+    check_consts::ConstCx, promote_consts::is_const_fn_in_array_repeat_expression,
+};
 
 use crate::borrow_check::{
     borrow_set::BorrowSet,
@@ -1098,6 +1101,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     ) -> Fallible<()> {
         relate_tys::relate_types(
             self.infcx,
+            self.param_env,
             a,
             v,
             b,
@@ -1988,18 +1992,24 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         Operand::Copy(..) | Operand::Constant(..) => {
                             // These are always okay: direct use of a const, or a value that can evidently be copied.
                         }
-                        Operand::Move(_) => {
+                        Operand::Move(place) => {
                             // Make sure that repeated elements implement `Copy`.
                             let span = body.source_info(location).span;
                             let ty = operand.ty(body, tcx);
                             if !self.infcx.type_is_copy_modulo_regions(self.param_env, ty, span) {
+                                let ccx = ConstCx::new_with_param_env(tcx, body, self.param_env);
+                                let is_const_fn =
+                                    is_const_fn_in_array_repeat_expression(&ccx, &place, &body);
+
+                                debug!("check_rvalue: is_const_fn={:?}", is_const_fn);
+
                                 let def_id = body.source.def_id().expect_local();
                                 self.infcx.report_selection_error(
                                     &traits::Obligation::new(
                                         ObligationCause::new(
                                             span,
                                             self.tcx().hir().local_def_id_to_hir_id(def_id),
-                                            traits::ObligationCauseCode::RepeatVec,
+                                            traits::ObligationCauseCode::RepeatVec(is_const_fn),
                                         ),
                                         self.param_env,
                                         ty::Binder::bind(ty::TraitRef::new(

compiler/rustc_mir/src/borrow_check/type_check/relate_tys.rs

@@ -18,6 +18,7 @@ use crate::borrow_check::type_check::{BorrowCheckContext, Locations};
 /// variables, but not the type `b`.
 pub(super) fn relate_types<'tcx>(
     infcx: &InferCtxt<'_, 'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
     a: Ty<'tcx>,
     v: ty::Variance,
     b: Ty<'tcx>,
@@ -28,7 +29,7 @@ pub(super) fn relate_types<'tcx>(
     debug!("relate_types(a={:?}, v={:?}, b={:?}, locations={:?})", a, v, b, locations);
     TypeRelating::new(
         infcx,
-        NllTypeRelatingDelegate::new(infcx, borrowck_context, locations, category),
+        NllTypeRelatingDelegate::new(infcx, borrowck_context, param_env, locations, category),
         v,
     )
     .relate(a, b)?;
@@ -39,6 +40,8 @@ struct NllTypeRelatingDelegate<'me, 'bccx, 'tcx> {
     infcx: &'me InferCtxt<'me, 'tcx>,
     borrowck_context: Option<&'me mut BorrowCheckContext<'bccx, 'tcx>>,
 
+    param_env: ty::ParamEnv<'tcx>,
+
     /// Where (and why) is this relation taking place?
     locations: Locations,
 
@@ -50,14 +53,19 @@ impl NllTypeRelatingDelegate<'me, 'bccx, 'tcx> {
     fn new(
         infcx: &'me InferCtxt<'me, 'tcx>,
         borrowck_context: Option<&'me mut BorrowCheckContext<'bccx, 'tcx>>,
+        param_env: ty::ParamEnv<'tcx>,
         locations: Locations,
         category: ConstraintCategory,
     ) -> Self {
-        Self { infcx, borrowck_context, locations, category }
+        Self { infcx, borrowck_context, param_env, locations, category }
     }
 }
 
 impl TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, 'tcx> {
+    fn param_env(&self) -> ty::ParamEnv<'tcx> {
+        self.param_env
+    }
+
     fn create_next_universe(&mut self) -> ty::UniverseIndex {
         self.infcx.create_next_universe()
     }

compiler/rustc_mir/src/const_eval/eval_queries.rs

@@ -208,7 +208,7 @@ pub fn eval_to_const_value_raw_provider<'tcx>(
     tcx: TyCtxt<'tcx>,
     key: ty::ParamEnvAnd<'tcx, GlobalId<'tcx>>,
 ) -> ::rustc_middle::mir::interpret::EvalToConstValueResult<'tcx> {
-    // see comment in const_eval_raw_provider for what we're doing here
+    // see comment in eval_to_allocation_raw_provider for what we're doing here
     if key.param_env.reveal() == Reveal::All {
         let mut key = key;
         key.param_env = key.param_env.with_user_facing();