Auto merge of rust-lang#127785 - matthiaskrgr:rollup-04q3ug0, r=matth…

…iaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#120990 (Suggest a borrow when using dbg)
 - rust-lang#127047 (fix least significant digits of f128 associated constants)
 - rust-lang#127629 (Suggest using `map_or` when `Option<&T>::unwrap_or where T: Deref` fails)
 - rust-lang#127770 (Update books)
 - rust-lang#127780 (Make sure trait def ids match before zipping args in `note_function_argument_obligation`)

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

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -4,7 +4,7 @@
 #![allow(rustc::untranslatable_diagnostic)]
 
 use either::Either;
-use hir::ClosureKind;
+use hir::{ClosureKind, Path};
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::{codes::*, struct_span_code_err, Applicability, Diag, MultiSpan};
@@ -16,6 +16,7 @@ use rustc_hir::{CoroutineKind, CoroutineSource, LangItem};
 use rustc_middle::bug;
 use rustc_middle::hir::nested_filter::OnlyBodies;
 use rustc_middle::mir::tcx::PlaceTy;
+use rustc_middle::mir::VarDebugInfoContents;
 use rustc_middle::mir::{
     self, AggregateKind, BindingForm, BorrowKind, CallSource, ClearCrossCrate, ConstraintCategory,
     FakeBorrowKind, FakeReadCause, LocalDecl, LocalInfo, LocalKind, Location, MutBorrowKind,
@@ -546,7 +547,14 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
                     self.suggest_cloning(err, ty, expr, None, Some(move_spans));
                 }
             }
-            if let Some(pat) = finder.pat {
+
+            self.suggest_ref_for_dbg_args(expr, place, move_span, err);
+
+            // it's useless to suggest inserting `ref` when the span don't comes from local code
+            if let Some(pat) = finder.pat
+                && !move_span.is_dummy()
+                && !self.infcx.tcx.sess.source_map().is_imported(move_span)
+            {
                 *in_pattern = true;
                 let mut sugg = vec![(pat.span.shrink_to_lo(), "ref ".to_string())];
                 if let Some(pat) = finder.parent_pat {
@@ -561,6 +569,59 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
         }
     }
 
+    // for dbg!(x) which may take ownership, suggest dbg!(&x) instead
+    // but here we actually do not check whether the macro name is `dbg!`
+    // so that we may extend the scope a bit larger to cover more cases
+    fn suggest_ref_for_dbg_args(
+        &self,
+        body: &hir::Expr<'_>,
+        place: &Place<'tcx>,
+        move_span: Span,
+        err: &mut Diag<'infcx>,
+    ) {
+        let var_info = self.body.var_debug_info.iter().find(|info| match info.value {
+            VarDebugInfoContents::Place(ref p) => p == place,
+            _ => false,
+        });
+        let arg_name = if let Some(var_info) = var_info {
+            var_info.name
+        } else {
+            return;
+        };
+        struct MatchArgFinder {
+            expr_span: Span,
+            match_arg_span: Option<Span>,
+            arg_name: Symbol,
+        }
+        impl Visitor<'_> for MatchArgFinder {
+            fn visit_expr(&mut self, e: &hir::Expr<'_>) {
+                // dbg! is expanded into a match pattern, we need to find the right argument span
+                if let hir::ExprKind::Match(expr, ..) = &e.kind
+                    && let hir::ExprKind::Path(hir::QPath::Resolved(
+                        _,
+                        path @ Path { segments: [seg], .. },
+                    )) = &expr.kind
+                    && seg.ident.name == self.arg_name
+                    && self.expr_span.source_callsite().contains(expr.span)
+                {
+                    self.match_arg_span = Some(path.span);
+                }
+                hir::intravisit::walk_expr(self, e);
+            }
+        }
+
+        let mut finder = MatchArgFinder { expr_span: move_span, match_arg_span: None, arg_name };
+        finder.visit_expr(body);
+        if let Some(macro_arg_span) = finder.match_arg_span {
+            err.span_suggestion_verbose(
+                macro_arg_span.shrink_to_lo(),
+                "consider borrowing instead of transferring ownership",
+                "&",
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+
     fn report_use_of_uninitialized(
         &self,
         mpi: MovePathIndex,

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -948,6 +948,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 &mut err,
             );
 
+            self.suggest_deref_unwrap_or(
+                &mut err,
+                error_span,
+                callee_ty,
+                call_ident,
+                expected_ty,
+                provided_ty,
+                provided_args[*provided_idx],
+                is_method,
+            );
+
             // Call out where the function is defined
             self.label_fn_like(
                 &mut err,

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1429,6 +1429,74 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         true
     }
 
+    // Suggest to change `Option<&Vec<T>>::unwrap_or(&[])` to `Option::map_or(&[], |v| v)`.
+    #[instrument(level = "trace", skip(self, err, provided_expr))]
+    pub(crate) fn suggest_deref_unwrap_or(
+        &self,
+        err: &mut Diag<'_>,
+        error_span: Span,
+        callee_ty: Option<Ty<'tcx>>,
+        call_ident: Option<Ident>,
+        expected_ty: Ty<'tcx>,
+        provided_ty: Ty<'tcx>,
+        provided_expr: &Expr<'tcx>,
+        is_method: bool,
+    ) {
+        if !is_method {
+            return;
+        }
+        let Some(callee_ty) = callee_ty else {
+            return;
+        };
+        let ty::Adt(callee_adt, _) = callee_ty.peel_refs().kind() else {
+            return;
+        };
+        let adt_name = if self.tcx.is_diagnostic_item(sym::Option, callee_adt.did()) {
+            "Option"
+        } else if self.tcx.is_diagnostic_item(sym::Result, callee_adt.did()) {
+            "Result"
+        } else {
+            return;
+        };
+
+        let Some(call_ident) = call_ident else {
+            return;
+        };
+        if call_ident.name != sym::unwrap_or {
+            return;
+        }
+
+        let ty::Ref(_, peeled, _mutability) = provided_ty.kind() else {
+            return;
+        };
+
+        // NOTE: Can we reuse `suggest_deref_or_ref`?
+
+        // Create an dummy type `&[_]` so that both &[] and `&Vec<T>` can coerce to it.
+        let dummy_ty = if let ty::Array(elem_ty, size) = peeled.kind()
+            && let ty::Infer(_) = elem_ty.kind()
+            && size.try_eval_target_usize(self.tcx, self.param_env) == Some(0)
+        {
+            let slice = Ty::new_slice(self.tcx, *elem_ty);
+            Ty::new_imm_ref(self.tcx, self.tcx.lifetimes.re_static, slice)
+        } else {
+            provided_ty
+        };
+
+        if !self.can_coerce(expected_ty, dummy_ty) {
+            return;
+        }
+        let msg = format!("use `{adt_name}::map_or` to deref inner value of `{adt_name}`");
+        err.multipart_suggestion_verbose(
+            msg,
+            vec![
+                (call_ident.span, "map_or".to_owned()),
+                (provided_expr.span.shrink_to_hi(), ", |v| v".to_owned()),
+            ],
+            Applicability::MachineApplicable,
+        );
+    }
+
     /// Suggest wrapping the block in square brackets instead of curly braces
     /// in case the block was mistaken array syntax, e.g. `{ 1 }` -> `[ 1 ]`.
     pub(crate) fn suggest_block_to_brackets(

compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs

@@ -3810,6 +3810,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             {
                 if let Some(where_pred) = where_pred.as_trait_clause()
                     && let Some(failed_pred) = failed_pred.as_trait_clause()
+                    && where_pred.def_id() == failed_pred.def_id()
                 {
                     self.enter_forall(where_pred, |where_pred| {
                         let failed_pred = self.instantiate_binder_with_fresh_vars(

library/core/src/num/f128.rs

@@ -170,15 +170,15 @@ impl f128 {
     /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
     /// [`MANTISSA_DIGITS`]: f128::MANTISSA_DIGITS
     #[unstable(feature = "f128", issue = "116909")]
-    pub const EPSILON: f128 = 1.92592994438723585305597794258492731e-34_f128;
+    pub const EPSILON: f128 = 1.92592994438723585305597794258492732e-34_f128;
 
     /// Smallest finite `f128` value.
     ///
     /// Equal to −[`MAX`].
     ///
     /// [`MAX`]: f128::MAX
     #[unstable(feature = "f128", issue = "116909")]
-    pub const MIN: f128 = -1.18973149535723176508575932662800701e+4932_f128;
+    pub const MIN: f128 = -1.18973149535723176508575932662800702e+4932_f128;
     /// Smallest positive normal `f128` value.
     ///
     /// Equal to 2<sup>[`MIN_EXP`]&nbsp;&minus;&nbsp;1</sup>.
@@ -194,7 +194,7 @@ impl f128 {
     /// [`MANTISSA_DIGITS`]: f128::MANTISSA_DIGITS
     /// [`MAX_EXP`]: f128::MAX_EXP
     #[unstable(feature = "f128", issue = "116909")]
-    pub const MAX: f128 = 1.18973149535723176508575932662800701e+4932_f128;
+    pub const MAX: f128 = 1.18973149535723176508575932662800702e+4932_f128;
 
     /// One greater than the minimum possible normal power of 2 exponent.
     ///

tests/ui/borrowck/dbg-issue-120327.rs

@@ -0,0 +1,68 @@
+fn s() -> String {
+    let a = String::new();
+    dbg!(a);
+    return a; //~ ERROR use of moved value:
+}
+
+fn m() -> String {
+    let a = String::new();
+    dbg!(1, 2, a, 1, 2);
+    return a; //~ ERROR use of moved value:
+}
+
+fn t(a: String) -> String {
+    let b: String = "".to_string();
+    dbg!(a, b);
+    return b; //~ ERROR use of moved value:
+}
+
+fn x(a: String) -> String {
+    let b: String = "".to_string();
+    dbg!(a, b);
+    return a; //~ ERROR use of moved value:
+}
+
+macro_rules! my_dbg {
+    () => {
+        eprintln!("[{}:{}:{}]", file!(), line!(), column!())
+    };
+    ($val:expr $(,)?) => {
+        match $val {
+            tmp => {
+                eprintln!("[{}:{}:{}] {} = {:#?}",
+                    file!(), line!(), column!(), stringify!($val), &tmp);
+                tmp
+            }
+        }
+    };
+    ($($val:expr),+ $(,)?) => {
+        ($(my_dbg!($val)),+,)
+    };
+}
+
+fn test_my_dbg() -> String {
+    let b: String = "".to_string();
+    my_dbg!(b, 1);
+    return b; //~ ERROR use of moved value:
+}
+
+fn test_not_macro() -> String {
+    let a = String::new();
+    let _b = match a {
+        tmp => {
+            eprintln!("dbg: {}", tmp);
+            tmp
+        }
+    };
+    return a; //~ ERROR use of moved value:
+}
+
+fn get_expr(_s: String) {}
+
+fn test() {
+    let a: String = "".to_string();
+    let _res = get_expr(dbg!(a));
+    let _l = a.len(); //~ ERROR borrow of moved value
+}
+
+fn main() {}