Auto merge of #155828 - JonathanBrouwer:rollup-w1XiFiF, r=<try>

Rollup of 10 pull requests


try-job: dist-various-1
try-job: test-various
try-job: x86_64-gnu-aux
try-job: x86_64-gnu-llvm-21-3
try-job: x86_64-msvc-1
try-job: aarch64-apple
try-job: x86_64-mingw-1
try-job: i686-msvc-2

Author: bors

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -156,14 +156,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                     .collect();
                 generic_args.push((kw::SelfUpper, this.clone()));
 
-                let args = FormatArgs {
-                    this,
-                    // Unused
-                    this_sugared: String::new(),
-                    // Unused
-                    item_context: "",
-                    generic_args,
-                };
+                let args = FormatArgs { this, generic_args, .. };
                 let CustomDiagnostic { message, label, notes, parent_label: _ } =
                     directive.eval(None, &args);
 

compiler/rustc_builtin_macros/src/format.rs

@@ -173,6 +173,16 @@ fn make_format_args(
         style: fmt_style,
         uncooked_symbol: uncooked_fmt_str,
     } = {
+        // Extract snippet so that we can check cases `{}`, `{:?}` and `{:#?}` and emit help for
+        // them later.
+        let snippet = if let ExprKind::Block(b, None) = &efmt.kind
+            && b.stmts.len() <= 1
+        {
+            Some(ecx.sess.source_map().span_to_snippet(unexpanded_fmt_span))
+        } else {
+            None
+        };
+
         let ExpandResult::Ready(mac) = expr_to_spanned_string(ecx, efmt.clone(), msg) else {
             return ExpandResult::Retry(());
         };
@@ -222,12 +232,26 @@ fn make_format_args(
                                     });
                                 }
                                 sugg_fmt = sugg_fmt.trim_end().to_string();
-                                err.span_suggestion(
+                                err.span_suggestion_verbose(
                                     unexpanded_fmt_span.shrink_to_lo(),
                                     "you might be missing a string literal to format with",
                                     format!("\"{sugg_fmt}\", "),
                                     Applicability::MaybeIncorrect,
                                 );
+
+                                if let Some(Ok(snippet)) = snippet.as_ref() {
+                                    match snippet.as_str() {
+                                        "{}" | "{:?}" | "{:#?}" => {
+                                            err.span_suggestion_verbose(
+                                                unexpanded_fmt_span,
+                                                format!("you might want to enclose `{snippet}` with `\"\"`"),
+                                                format!("\"{snippet}\""),
+                                                Applicability::MaybeIncorrect,
+                                            );
+                                        }
+                                        _ => {}
+                                    };
+                                }
                             }
                         }
                         err.emit()

compiler/rustc_expand/src/lib.rs

@@ -1,6 +1,7 @@
 // tidy-alphabetical-start
 #![allow(internal_features)]
 #![feature(associated_type_defaults)]
+#![feature(default_field_values)]
 #![feature(macro_metavar_expr)]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_internals)]

compiler/rustc_expand/src/mbe/diagnostics.rs

@@ -77,19 +77,8 @@ pub(super) fn failed_to_match_macro(
     let CustomDiagnostic {
         message: custom_message, label: custom_label, notes: custom_notes, ..
     } = {
-        let macro_name = name.to_string();
         on_unmatch_args
-            .map(|directive| {
-                directive.eval(
-                    None,
-                    &FormatArgs {
-                        this: macro_name.clone(),
-                        this_sugared: macro_name,
-                        item_context: "macro invocation",
-                        generic_args: Vec::new(),
-                    },
-                )
-            })
+            .map(|directive| directive.eval(None, &FormatArgs { this: name.to_string(), .. }))
             .unwrap_or_default()
     };
 

compiler/rustc_hir/src/attrs/diagnostic.rs

@@ -218,10 +218,11 @@ impl FormatString {
 /// ```
 #[derive(Debug)]
 pub struct FormatArgs {
+    /// The name of the item the attribute is on.
     pub this: String,
-    pub this_sugared: String,
-    pub item_context: &'static str,
-    pub generic_args: Vec<(Symbol, String)>,
+    pub this_sugared: String = String::new(),
+    pub item_context: &'static str = "",
+    pub generic_args: Vec<(Symbol, String)> = Vec::new(),
 }
 
 #[derive(Clone, Debug, HashStable_Generic, Encodable, Decodable, PrintAttribute)]

compiler/rustc_hir/src/lib.rs

@@ -7,6 +7,7 @@
 #![feature(closure_track_caller)]
 #![feature(const_default)]
 #![feature(const_trait_impl)]
+#![feature(default_field_values)]
 #![feature(derive_const)]
 #![feature(exhaustive_patterns)]
 #![feature(never_type)]

compiler/rustc_hir_typeck/src/expr_use_visitor.rs

@@ -2,7 +2,7 @@
 //! normal visitor, which just walks the entire body in one shot, the
 //! `ExprUseVisitor` determines how expressions are being used.
 //!
-//! In the compiler, this is only used for upvar inference, but there
+//! In the compiler, this is only used for upvar inference and diagnostics, but there
 //! are many uses within clippy.
 
 use std::cell::{Ref, RefCell};
@@ -1855,3 +1855,27 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx
         }
     }
 }
+
+struct ExprPlaceDelegate;
+
+impl<'tcx> Delegate<'tcx> for ExprPlaceDelegate {
+    fn consume(&mut self, _: &PlaceWithHirId<'tcx>, _: HirId) {}
+
+    fn use_cloned(&mut self, _: &PlaceWithHirId<'tcx>, _: HirId) {}
+
+    fn borrow(&mut self, _: &PlaceWithHirId<'tcx>, _: HirId, _: ty::BorrowKind) {}
+
+    fn mutate(&mut self, _: &PlaceWithHirId<'tcx>, _: HirId) {}
+
+    fn fake_read(&mut self, _: &PlaceWithHirId<'tcx>, _: FakeReadCause, _: HirId) {}
+}
+
+/// Categorizes `expr` as a place for diagnostic suggestions.
+///
+/// This should be used for diagnostics purpose only.
+pub(crate) fn expr_place<'tcx>(
+    fcx: &FnCtxt<'_, 'tcx>,
+    expr: &hir::Expr<'_>,
+) -> Result<PlaceWithHirId<'tcx>, ErrorGuaranteed> {
+    ExprUseVisitor::new(fcx, ExprPlaceDelegate).cat_expr(expr)
+}

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -48,6 +48,7 @@ use tracing::{debug, info, instrument};
 use super::probe::{AutorefOrPtrAdjustment, IsSuggestion, Mode, ProbeScope};
 use super::{CandidateSource, MethodError, NoMatchData};
 use crate::errors::{self, CandidateTraitNote, NoAssociatedItem};
+use crate::expr_use_visitor::expr_place;
 use crate::method::probe::UnsatisfiedPredicates;
 use crate::{Expectation, FnCtxt};
 
@@ -189,6 +190,70 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         false
     }
 
+    // Pick the iterator method to suggest: `.into_iter()` by default, and
+    // `.iter()`/`.iter_mut()` for projections through references.
+    fn preferred_iterator_method(
+        &self,
+        source: SelfSource<'tcx>,
+        rcvr_ty: Ty<'tcx>,
+    ) -> Option<Symbol> {
+        let SelfSource::MethodCall(rcvr_expr) = source else {
+            return Some(sym::into_iter);
+        };
+
+        let rcvr_expr = rcvr_expr.peel_drop_temps().peel_blocks();
+        let Ok(place_with_id) = expr_place(self, rcvr_expr) else {
+            return None;
+        };
+
+        let mut projection_mutability = None;
+        for pointer_ty in place_with_id.place.deref_tys() {
+            match self.structurally_resolve_type(rcvr_expr.span, pointer_ty).kind() {
+                ty::Ref(.., Mutability::Not) => {
+                    projection_mutability = Some(Mutability::Not);
+                    break;
+                }
+                ty::Ref(.., Mutability::Mut) => {
+                    projection_mutability.get_or_insert(Mutability::Mut);
+                }
+                ty::RawPtr(..) => return None,
+                _ => {}
+            }
+        }
+
+        // Keep `.into_iter()` for receivers like `&Vec<_>`; only projections that
+        // dereference a reference need to switch to `iter`/`iter_mut`.
+        let Some(projection_mutability) = projection_mutability else {
+            return Some(sym::into_iter);
+        };
+
+        let call_expr = self.tcx.hir_expect_expr(self.tcx.parent_hir_id(rcvr_expr.hir_id));
+        // `IntoIterator` does not imply inherent `iter`/`iter_mut` methods.
+        let has_method = |method_name| {
+            self.lookup_probe_for_diagnostic(
+                Ident::with_dummy_span(method_name),
+                rcvr_ty,
+                call_expr,
+                ProbeScope::TraitsInScope,
+                None,
+            )
+            .is_ok()
+        };
+
+        match projection_mutability {
+            Mutability::Not => has_method(sym::iter).then_some(sym::iter),
+            Mutability::Mut => {
+                if has_method(sym::iter_mut) {
+                    Some(sym::iter_mut)
+                } else if has_method(sym::iter) {
+                    Some(sym::iter)
+                } else {
+                    None
+                }
+            }
+        }
+    }
+
     #[instrument(level = "debug", skip(self))]
     pub(crate) fn report_method_error(
         &self,
@@ -855,10 +920,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         } else if self.impl_into_iterator_should_be_iterator(rcvr_ty, span, unsatisfied_predicates)
         {
             err.span_label(span, format!("`{rcvr_ty}` is not an iterator"));
-            if !span.in_external_macro(self.tcx.sess.source_map()) {
+            if !span.in_external_macro(self.tcx.sess.source_map())
+                && let Some(method_name) = self.preferred_iterator_method(source, rcvr_ty)
+            {
                 err.multipart_suggestion(
-                    "call `.into_iter()` first",
-                    vec![(span.shrink_to_lo(), format!("into_iter()."))],
+                    format!("call `.{method_name}()` first"),
+                    vec![(span.shrink_to_lo(), format!("{method_name}()."))],
                     Applicability::MaybeIncorrect,
                 );
             }

compiler/rustc_lint_defs/src/builtin.rs

@@ -5639,7 +5639,12 @@ declare_lint! {
     /// LLVM periodically updates its list of intrinsics. Deprecated intrinsics are unlikely
     /// to be removed, but they may optimize less well than their new versions, so it's
     /// best to use the new version. Also, some deprecated intrinsics might have buggy
-    /// behavior
+    /// behavior.
+    ///
+    /// This `link_llvm_intrinsics` lint is intended to be used internally only, and requires the
+    /// `#![feature(link_llvm_intrinsics)]` internal feature gate. For more information, see [its chapter in
+    /// the Unstable Book](https://doc.rust-lang.org/unstable-book/language-features/link-llvm-intrinsics.html)
+    /// and [its tracking issue](https://github.com/rust-lang/rust/issues/29602).
     pub DEPRECATED_LLVM_INTRINSIC,
     Allow,
     "detects uses of deprecated LLVM intrinsics",

compiler/rustc_parse/src/errors.rs

@@ -1140,29 +1140,27 @@ pub(crate) struct InclusiveRangeMatchArrow {
     #[primary_span]
     pub arrow: Span,
     #[label("this is parsed as an inclusive range `..=`")]
-    pub span: Span,
     #[suggestion(
         "add a space between the pattern and `=>`",
         style = "verbose",
-        code = " ",
+        code = ".. =",
         applicability = "machine-applicable"
     )]
-    pub after_pat: Span,
+    pub span: Span,
 }
 
 #[derive(Diagnostic)]
 #[diag("inclusive range with no end", code = E0586)]
 #[note("inclusive ranges must be bounded at the end (`..=b` or `a..=b`)")]
 pub(crate) struct InclusiveRangeNoEnd {
     #[primary_span]
-    pub span: Span,
     #[suggestion(
         "use `..` instead",
-        code = "",
+        code = "..",
         applicability = "machine-applicable",
         style = "verbose"
     )]
-    pub suggestion: Span,
+    pub span: Span,
 }
 
 #[derive(Subdiagnostic)]