Auto merge of #155851 - jhpratt:rollup-Jst4hhC, r=jhpratt

Rollup of 12 pull requests

Successful merges:

 - #149624 (Fix requires_lto targets needing lto set in cargo)
 - #155317 (`std::io::Take`: Clarify & optimize `BorrowedBuf::set_init` usage.)
 - #155579 (Make Rcs and Arcs use pointer comparison for unsized types)
 - #155588 (Implement more traits for FRTs)
 - #155708 (Fix heap overflow in slice::join caused by misbehaving Borrow)
 - #155778 (Avoid Vec allocation in TyCtxt::mk_place_elem)
 - #151014 (std: sys: process: uefi: Add program searching)
 - #155682 (Add boxing suggestions for `impl Trait` return type mismatches)
 - #155770 (Avoid misleading closure return type note)
 - #155818 (Convert attribute `FinalizeFn` to fn pointer)
 - #155829 (rustc_attr_parsing: use a `try {}` in `or_malformed`)
 - #155835 (couple of `crate_name` cleanups)

Author: bors

compiler/rustc_attr_parsing/src/attributes/diagnostic/mod.rs

@@ -236,9 +236,11 @@ fn parse_directive_items<'p, S: Stage>(
         }}
 
         macro or_malformed($($code:tt)*) {{
-            let Some(ret) = (||{
-                Some($($code)*)
-            })() else {
+            let Some(ret) = (
+                try {
+                    $($code)*
+                }
+            ) else {
                 malformed!()
             };
             ret

compiler/rustc_attr_parsing/src/context.rs

@@ -84,8 +84,7 @@ pub(super) struct GroupTypeInnerAccept<S: Stage> {
 
 pub(crate) type AcceptFn<S> =
     Box<dyn for<'sess, 'a> Fn(&mut AcceptContext<'_, 'sess, S>, &ArgParser) + Send + Sync>;
-pub(crate) type FinalizeFn<S> =
-    Box<dyn Send + Sync + Fn(&mut FinalizeContext<'_, '_, S>) -> Option<AttributeKind>>;
+pub(crate) type FinalizeFn<S> = fn(&mut FinalizeContext<'_, '_, S>) -> Option<AttributeKind>;
 
 macro_rules! attribute_parsers {
     (
@@ -131,10 +130,10 @@ macro_rules! attribute_parsers {
                                     }),
                                     safety: <$names as crate::attributes::AttributeParser<$stage>>::SAFETY,
                                     allowed_targets: <$names as crate::attributes::AttributeParser<$stage>>::ALLOWED_TARGETS,
-                                    finalizer: Box::new(|cx| {
+                                    finalizer: |cx| {
                                         let state = STATE_OBJECT.take();
                                         state.finalize(cx)
-                                    })
+                                    }
                                 });
                             }
                             Entry::Occupied(_) => panic!("Attribute {path:?} has multiple accepters"),

compiler/rustc_attr_parsing/src/interface.rs

@@ -297,7 +297,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
         let mut attr_paths: Vec<RefPathParser<'_>> = Vec::new();
         let mut early_parsed_state = EarlyParsedState::default();
 
-        let mut finalizers: Vec<&FinalizeFn<S>> = Vec::with_capacity(attrs.len());
+        let mut finalizers: Vec<FinalizeFn<S>> = Vec::with_capacity(attrs.len());
 
         for attr in attrs {
             // If we're only looking for a single attribute, skip all the ones we don't care about.
@@ -413,7 +413,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
                         };
 
                         (accept.accept_fn)(&mut cx, &args);
-                        finalizers.push(&accept.finalizer);
+                        finalizers.push(accept.finalizer);
 
                         if !matches!(cx.stage.should_emit(), ShouldEmit::Nothing) {
                             Self::check_target(&accept.allowed_targets, target, &mut cx);

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -153,7 +153,7 @@ impl ModuleConfig {
             // `#![no_builtins]` is assumed to not participate in LTO and
             // instead goes on to generate object code.
             EmitObj::Bitcode
-        } else if need_bitcode_in_object(tcx) {
+        } else if need_bitcode_in_object(tcx) || sess.target.requires_lto {
             EmitObj::ObjectCode(BitcodeSection::Full)
         } else {
             EmitObj::ObjectCode(BitcodeSection::None)

compiler/rustc_hir_typeck/src/coercion.rs

@@ -2009,6 +2009,9 @@ impl<'tcx> CoerceMany<'tcx> {
             // note in this case, since it would be incorrect.
             && let Some(fn_sig) = fcx.body_fn_sig()
             && fn_sig.output().is_ty_var()
+            && fcx.ret_coercion.as_ref().is_some_and(|ret_coercion| {
+                fcx.resolve_vars_if_possible(ret_coercion.borrow().expected_ty()) == expected
+            })
         {
             err.span_note(sp, format!("return type inferred to be `{expected}` here"));
         }

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -7,6 +7,7 @@ use rustc_ast::util::parser::ExprPrecedence;
 use rustc_data_structures::packed::Pu128;
 use rustc_errors::{Applicability, Diag, MultiSpan, listify, msg};
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
+use rustc_hir::intravisit::Visitor;
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{
     self as hir, Arm, CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, ExprKind,
@@ -26,13 +27,14 @@ use rustc_session::errors::ExprParenthesesNeeded;
 use rustc_span::{ExpnKind, Ident, MacroKind, Span, Spanned, Symbol, sym};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::error_reporting::traits::DefIdOrName;
+use rustc_trait_selection::error_reporting::traits::suggestions::ReturnsVisitor;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 use tracing::{debug, instrument};
 
 use super::FnCtxt;
-use crate::errors;
+use crate::errors::{self, SuggestBoxingForReturnImplTrait};
 use crate::fn_ctxt::rustc_span::BytePos;
 use crate::method::probe;
 use crate::method::probe::{IsSuggestion, Mode, ProbeScope};
@@ -963,6 +965,40 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         );
                     }
 
+                    let trait_def_id = trait_ref.trait_ref.path.res.def_id();
+                    if self.tcx.is_dyn_compatible(trait_def_id) {
+                        err.subdiagnostic(SuggestBoxingForReturnImplTrait::ChangeReturnType {
+                            start_sp: hir_ty.span.with_hi(hir_ty.span.lo() + BytePos(4)),
+                            end_sp: hir_ty.span.shrink_to_hi(),
+                        });
+
+                        let body = self.tcx.hir_body_owned_by(fn_id);
+                        let mut visitor = ReturnsVisitor::default();
+                        visitor.visit_body(&body);
+
+                        if !visitor.returns.is_empty() {
+                            let starts: Vec<Span> = visitor
+                                .returns
+                                .iter()
+                                .filter(|expr| expr.span.can_be_used_for_suggestions())
+                                .map(|expr| expr.span.shrink_to_lo())
+                                .collect();
+                            let ends: Vec<Span> = visitor
+                                .returns
+                                .iter()
+                                .filter(|expr| expr.span.can_be_used_for_suggestions())
+                                .map(|expr| expr.span.shrink_to_hi())
+                                .collect();
+
+                            if !starts.is_empty() {
+                                err.subdiagnostic(SuggestBoxingForReturnImplTrait::BoxReturnExpr {
+                                    starts,
+                                    ends,
+                                });
+                            }
+                        }
+                    }
+
                     self.try_suggest_return_impl_trait(err, expected, found, fn_id);
                     self.try_note_caller_chooses_ty_for_ty_param(err, expected, found);
                     return true;

compiler/rustc_middle/src/error.rs

@@ -143,7 +143,7 @@ pub(crate) struct Reentrant;
 #[note(
     "an ideal reproduction consists of the code before and some patch that then triggers the bug when applied and compiled again"
 )]
-#[note("as a workaround, you can run {$run_cmd} to allow your project to compile")]
+#[note("as a workaround, you can {$run_cmd} to allow your project to compile")]
 pub(crate) struct IncrementCompilation {
     pub run_cmd: String,
     pub dep_node: String,

compiler/rustc_middle/src/ty/context.rs

@@ -2416,10 +2416,10 @@ impl<'tcx> TyCtxt<'tcx> {
     /// to build a full `Place` it's just a convenient way to grab a projection and modify it in
     /// flight.
     pub fn mk_place_elem(self, place: Place<'tcx>, elem: PlaceElem<'tcx>) -> Place<'tcx> {
-        let mut projection = place.projection.to_vec();
-        projection.push(elem);
-
-        Place { local: place.local, projection: self.mk_place_elems(&projection) }
+        Place {
+            local: place.local,
+            projection: self.mk_place_elems_from_iter(place.projection.iter().chain([elem])),
+        }
     }
 
     pub fn mk_poly_existential_predicates(

compiler/rustc_middle/src/verify_ich.rs

@@ -1,6 +1,8 @@
 use std::cell::Cell;
 
 use rustc_data_structures::fingerprint::Fingerprint;
+use rustc_hir::def_id::LOCAL_CRATE;
+use rustc_session::utils::was_invoked_from_cargo;
 use tracing::instrument;
 
 use crate::dep_graph::{DepGraphData, SerializedDepNodeIndex};
@@ -66,10 +68,10 @@ fn incremental_verify_ich_failed<'tcx>(
     if old_in_panic {
         tcx.dcx().emit_err(crate::error::Reentrant);
     } else {
-        let run_cmd = if let Some(crate_name) = &tcx.sess.opts.crate_name {
-            format!("`cargo clean -p {crate_name}` or `cargo clean`")
+        let run_cmd = if was_invoked_from_cargo() {
+            format!("run `cargo clean -p {}` or `cargo clean`", tcx.crate_name(LOCAL_CRATE))
         } else {
-            "`cargo clean`".to_string()
+            "clean your build cache".to_owned()
         };
 
         let dep_node = tcx.dep_graph.data().unwrap().prev_node_of(prev_index);

compiler/rustc_session/src/config.rs

@@ -1205,6 +1205,7 @@ impl OutputFilenames {
     }
 
     pub fn interface_path(&self) -> PathBuf {
+        debug!("using crate_name={} for interface_path", self.crate_stem);
         self.out_directory.join(format!("lib{}.rs", self.crate_stem))
     }
 
@@ -1214,6 +1215,7 @@ impl OutputFilenames {
         let extension = flavor.extension();
         match flavor {
             OutputType::Metadata => {
+                debug!("using crate_name={} for {extension}", self.crate_stem);
                 self.out_directory.join(format!("lib{}.{}", self.crate_stem, extension))
             }
             _ => self.with_directory_and_extension(&self.out_directory, extension),
@@ -1288,6 +1290,7 @@ impl OutputFilenames {
     }
 
     pub fn with_directory_and_extension(&self, directory: &Path, extension: &str) -> PathBuf {
+        debug!("using filestem={} for {extension}", self.filestem);
         let mut path = directory.join(&self.filestem);
         path.set_extension(extension);
         path