Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 66 insertions, 25 deletions

diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 56b1fd369..2fcb45ef8 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -36,7 +36,7 @@ use rustc_middle::ty::{
 use rustc_session::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::symbol::{kw, Ident, Symbol};
-use rustc_span::{sym, Span, DUMMY_SP};
+use rustc_span::{sym, BytePos, Span, DUMMY_SP};
 use rustc_target::spec::abi;
 use rustc_trait_selection::traits::wf::object_region_bounds;
 use rustc_trait_selection::traits::{self, NormalizeExt, ObligationCtxt};
@@ -567,9 +567,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         );
 
         if let ty::BoundConstness::ConstIfConst = constness
-            && generics.has_self && !tcx.has_attr(def_id, sym::const_trait)
+            && generics.has_self
+            && !tcx.has_attr(def_id, sym::const_trait)
         {
-            tcx.sess.emit_err(crate::errors::ConstBoundForNonConstTrait { span } );
+            tcx.sess.emit_err(crate::errors::ConstBoundForNonConstTrait { span });
         }
 
         (args, arg_count)
@@ -915,7 +916,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             // Type aliases defined in crates that have the
             // feature `lazy_type_alias` enabled get encoded as a type alias that normalization will
             // then actually instantiate the where bounds of.
-            let alias_ty = tcx.mk_alias_ty(did, args);
+            let alias_ty = ty::AliasTy::new(tcx, did, args);
             Ty::new_alias(tcx, ty::Weak, alias_ty)
         } else {
             tcx.at(span).type_of(did).instantiate(tcx, args)
@@ -1017,7 +1018,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     }
                     err.span_suggestions(
                         span,
-                        "use the fully-qualified path",
+                        "use fully-qualified syntax",
                         suggestions,
                         Applicability::MachineApplicable,
                     );
@@ -1061,6 +1062,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 )
             },
             param_name,
+            Some(ty_param_def_id),
             assoc_name,
             span,
             None,
@@ -1074,6 +1076,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         &self,
         all_candidates: impl Fn() -> I,
         ty_param_name: impl Display,
+        ty_param_def_id: Option<LocalDefId>,
         assoc_name: Ident,
         span: Span,
         is_equality: Option<ty::Term<'tcx>>,
@@ -1088,13 +1091,15 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             self.trait_defines_associated_item_named(r.def_id(), ty::AssocKind::Const, assoc_name)
         });
 
-        let (bound, next_cand) = match (matching_candidates.next(), const_candidates.next()) {
+        let (mut bound, mut next_cand) = match (matching_candidates.next(), const_candidates.next())
+        {
             (Some(bound), _) => (bound, matching_candidates.next()),
             (None, Some(bound)) => (bound, const_candidates.next()),
             (None, None) => {
                 let reported = self.complain_about_assoc_type_not_found(
                     all_candidates,
                     &ty_param_name.to_string(),
+                    ty_param_def_id,
                     assoc_name,
                     span,
                 );
@@ -1103,6 +1108,37 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         };
         debug!(?bound);
 
+        // look for a candidate that is not the same as our first bound, disregarding
+        // whether the bound is const.
+        while let Some(mut bound2) = next_cand {
+            debug!(?bound2);
+            let tcx = self.tcx();
+            if bound2.bound_vars() != bound.bound_vars() {
+                break;
+            }
+
+            let generics = tcx.generics_of(bound.def_id());
+            let Some(host_index) = generics.host_effect_index else { break };
+
+            // always return the bound that contains the host param.
+            if let ty::ConstKind::Param(_) = bound2.skip_binder().args.const_at(host_index).kind() {
+                (bound, bound2) = (bound2, bound);
+            }
+
+            let unconsted_args = bound
+                .skip_binder()
+                .args
+                .iter()
+                .enumerate()
+                .map(|(n, arg)| if host_index == n { tcx.consts.true_.into() } else { arg });
+
+            if unconsted_args.eq(bound2.skip_binder().args.iter()) {
+                next_cand = matching_candidates.next().or_else(|| const_candidates.next());
+            } else {
+                break;
+            }
+        }
+
         if let Some(bound2) = next_cand {
             debug!(?bound2);
 
@@ -1142,30 +1178,26 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     err.span_label(
                         bound_span,
                         format!(
-                            "ambiguous `{}` from `{}`",
-                            assoc_name,
+                            "ambiguous `{assoc_name}` from `{}`",
                             bound.print_only_trait_path(),
                         ),
                     );
                     if let Some(constraint) = &is_equality {
                         where_bounds.push(format!(
-                            "        T: {trait}::{assoc} = {constraint}",
+                            "        T: {trait}::{assoc_name} = {constraint}",
                             trait=bound.print_only_trait_path(),
-                            assoc=assoc_name,
-                            constraint=constraint,
                         ));
                     } else {
                         err.span_suggestion_verbose(
                             span.with_hi(assoc_name.span.lo()),
-                            "use fully qualified syntax to disambiguate",
-                            format!("<{} as {}>::", ty_param_name, bound.print_only_trait_path()),
+                            "use fully-qualified syntax to disambiguate",
+                            format!("<{ty_param_name} as {}>::", bound.print_only_trait_path()),
                             Applicability::MaybeIncorrect,
                         );
                     }
                 } else {
                     err.note(format!(
-                        "associated type `{}` could derive from `{}`",
-                        ty_param_name,
+                        "associated type `{ty_param_name}` could derive from `{}`",
                         bound.print_only_trait_path(),
                     ));
                 }
@@ -1173,8 +1205,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             if !where_bounds.is_empty() {
                 err.help(format!(
                     "consider introducing a new type parameter `T` and adding `where` constraints:\
-                     \n    where\n        T: {},\n{}",
-                    ty_param_name,
+                     \n    where\n        T: {ty_param_name},\n{}",
                     where_bounds.join(",\n"),
                 ));
             }
@@ -1275,8 +1306,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                 return;
                             };
                             // Get the span of the generics args *including* the leading `::`.
-                            let args_span =
-                                assoc_segment.ident.span.shrink_to_hi().to(args.span_ext);
+                            // We do so by stretching args.span_ext to the left by 2. Earlier
+                            // it was done based on the end of assoc segment but that sometimes
+                            // led to impossible spans and caused issues like #116473
+                            let args_span = args.span_ext.with_lo(args.span_ext.lo() - BytePos(2));
                             if tcx.generics_of(adt_def.did()).count() == 0 {
                                 // FIXME(estebank): we could also verify that the arguments being
                                 // work for the `enum`, instead of just looking if it takes *any*.
@@ -1394,6 +1427,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         )
                     },
                     kw::SelfUpper,
+                    None,
                     assoc_ident,
                     span,
                     None,
@@ -1684,7 +1718,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     .chain(args.into_iter().skip(parent_args.len())),
             );
 
-            let ty = Ty::new_alias(tcx, ty::Inherent, tcx.mk_alias_ty(assoc_item, args));
+            let ty = Ty::new_alias(tcx, ty::Inherent, ty::AliasTy::new(tcx, assoc_item, args));
 
             return Ok(Some((ty, assoc_item)));
         }
@@ -1917,9 +1951,12 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     } else {
                         Some((
                             match segment.res {
-                                Res::PrimTy(ty) => format!("{} `{}`", segment.res.descr(), ty.name()),
+                                Res::PrimTy(ty) => {
+                                    format!("{} `{}`", segment.res.descr(), ty.name())
+                                }
                                 Res::Def(_, def_id)
-                                if let Some(name) = self.tcx().opt_item_name(def_id) => {
+                                    if let Some(name) = self.tcx().opt_item_name(def_id) =>
+                                {
                                     format!("{} `{name}`", segment.res.descr())
                                 }
                                 Res::Err => "this type".to_string(),
@@ -2249,7 +2286,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         err.note(msg);
                     }
                     for segment in path.segments {
-                        if let Some(args) = segment.args && segment.ident.name == kw::SelfUpper {
+                        if let Some(args) = segment.args
+                            && segment.ident.name == kw::SelfUpper
+                        {
                             if generics == 0 {
                                 // FIXME(estebank): we could also verify that the arguments being
                                 // work for the `enum`, instead of just looking if it takes *any*.
@@ -2631,7 +2670,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             .iter()
             .enumerate()
             .map(|(i, a)| {
-                if let hir::TyKind::Infer = a.kind && !self.allow_ty_infer() {
+                if let hir::TyKind::Infer = a.kind
+                    && !self.allow_ty_infer()
+                {
                     if let Some(suggested_ty) =
                         self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i))
                     {
@@ -2660,7 +2701,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     self.ast_ty_to_ty(output)
                 }
             }
-            hir::FnRetTy::DefaultReturn(..) => Ty::new_unit(tcx,),
+            hir::FnRetTy::DefaultReturn(..) => Ty::new_unit(tcx),
         };
 
         debug!(?output_ty);