Merge pull request rust-lang#20100 from ShoyuVanilla/ignore-sized-hierarchy

Backport new sized-hierarchy trait bounds in old ways

Author: ChayimFriedman2

src/tools/rust-analyzer/crates/hir-def/src/lang_item.rs

@@ -308,6 +308,8 @@ impl LangItem {
 language_item_table! {
 //  Variant name,            Name,                     Getter method name,         Target                  Generic requirements;
     Sized,                   sym::sized,               sized_trait,                Target::Trait,          GenericRequirement::Exact(0);
+    MetaSized,               sym::meta_sized,          sized_trait,                Target::Trait,          GenericRequirement::Exact(0);
+    PointeeSized,            sym::pointee_sized,       sized_trait,                Target::Trait,          GenericRequirement::Exact(0);
     Unsize,                  sym::unsize,              unsize_trait,               Target::Trait,          GenericRequirement::Minimum(1);
     /// Trait injected by `#[derive(PartialEq)]`, (i.e. "Partial EQ").
     StructuralPeq,           sym::structural_peq,      structural_peq_trait,       Target::Trait,          GenericRequirement::None;

src/tools/rust-analyzer/crates/hir-ty/src/lower.rs

@@ -581,11 +581,28 @@ impl<'a> TyLoweringContext<'a> {
         match bound {
             &TypeBound::Path(path, TraitBoundModifier::None) | &TypeBound::ForLifetime(_, path) => {
                 // FIXME Don't silently drop the hrtb lifetimes here
-                if let Some((trait_ref, ctx)) = self.lower_trait_ref_from_path(path, self_ty) {
-                    if !ignore_bindings {
-                        assoc_bounds = ctx.assoc_type_bindings_from_type_bound(trait_ref.clone());
+                if let Some((trait_ref, mut ctx)) =
+                    self.lower_trait_ref_from_path(path, self_ty.clone())
+                {
+                    // FIXME(sized-hierarchy): Remove this bound modifications once we have implemented
+                    // sized-hierarchy correctly.
+                    let meta_sized = LangItem::MetaSized
+                        .resolve_trait(ctx.ty_ctx().db, ctx.ty_ctx().resolver.krate());
+                    let pointee_sized = LangItem::PointeeSized
+                        .resolve_trait(ctx.ty_ctx().db, ctx.ty_ctx().resolver.krate());
+                    if meta_sized.is_some_and(|it| it == trait_ref.hir_trait_id()) {
+                        // Ignore this bound
+                    } else if pointee_sized.is_some_and(|it| it == trait_ref.hir_trait_id()) {
+                        // Regard this as `?Sized` bound
+                        ctx.ty_ctx().unsized_types.insert(self_ty);
+                    } else {
+                        if !ignore_bindings {
+                            assoc_bounds =
+                                ctx.assoc_type_bindings_from_type_bound(trait_ref.clone());
+                        }
+                        clause =
+                            Some(crate::wrap_empty_binders(WhereClause::Implemented(trait_ref)));
                     }
-                    clause = Some(crate::wrap_empty_binders(WhereClause::Implemented(trait_ref)));
                 }
             }
             &TypeBound::Path(path, TraitBoundModifier::Maybe) => {
@@ -945,8 +962,32 @@ pub(crate) fn generic_predicates_for_param_query(
         | WherePredicate::TypeBound { target, bound, .. } => {
             let invalid_target = { ctx.lower_ty_only_param(*target) != Some(param_id) };
             if invalid_target {
-                // If this is filtered out without lowering, `?Sized` is not gathered into `ctx.unsized_types`
-                if let TypeBound::Path(_, TraitBoundModifier::Maybe) = bound {
+                // FIXME(sized-hierarchy): Revisit and adjust this properly once we have implemented
+                // sized-hierarchy correctly.
+                // If this is filtered out without lowering, `?Sized` or `PointeeSized` is not gathered into
+                // `ctx.unsized_types`
+                let lower = || -> bool {
+                    match bound {
+                        TypeBound::Path(_, TraitBoundModifier::Maybe) => true,
+                        TypeBound::Path(path, _) | TypeBound::ForLifetime(_, path) => {
+                            let TypeRef::Path(path) = &ctx.store[path.type_ref()] else {
+                                return false;
+                            };
+                            let Some(pointee_sized) =
+                                LangItem::PointeeSized.resolve_trait(ctx.db, ctx.resolver.krate())
+                            else {
+                                return false;
+                            };
+                            // Lower the path directly with `Resolver` instead of PathLoweringContext`
+                            // to prevent diagnostics duplications.
+                            ctx.resolver.resolve_path_in_type_ns_fully(ctx.db, path).is_some_and(
+                                |it| matches!(it, TypeNs::TraitId(tr) if tr == pointee_sized),
+                            )
+                        }
+                        _ => false,
+                    }
+                }();
+                if lower {
                     ctx.lower_where_predicate(pred, true).for_each(drop);
                 }
                 return false;

src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_enum_is_method.rs

@@ -1,3 +1,5 @@
+use std::slice;
+
 use ide_db::assists::GroupLabel;
 use stdx::to_lower_snake_case;
 use syntax::ast::HasVisibility;
@@ -52,7 +54,7 @@ pub(crate) fn generate_enum_is_method(acc: &mut Assists, ctx: &AssistContext<'_>
     let fn_name = format!("is_{}", &to_lower_snake_case(&variant_name.text()));
 
     // Return early if we've found an existing new fn
-    let impl_def = find_struct_impl(ctx, &parent_enum, &[fn_name.clone()])?;
+    let impl_def = find_struct_impl(ctx, &parent_enum, slice::from_ref(&fn_name))?;
 
     let target = variant.syntax().text_range();
     acc.add_group(

src/tools/rust-analyzer/crates/ide-assists/src/handlers/generate_enum_projection_method.rs

@@ -1,3 +1,5 @@
+use std::slice;
+
 use ide_db::assists::GroupLabel;
 use itertools::Itertools;
 use stdx::to_lower_snake_case;
@@ -148,7 +150,7 @@ fn generate_enum_projection_method(
     let fn_name = format!("{fn_name_prefix}_{}", &to_lower_snake_case(&variant_name.text()));
 
     // Return early if we've found an existing new fn
-    let impl_def = find_struct_impl(ctx, &parent_enum, &[fn_name.clone()])?;
+    let impl_def = find_struct_impl(ctx, &parent_enum, slice::from_ref(&fn_name))?;
 
     let target = variant.syntax().text_range();
     acc.add_group(

src/tools/rust-analyzer/crates/ide/src/inlay_hints/bounds.rs

@@ -143,7 +143,7 @@ fn foo<T>() {}
                                             file_id: FileId(
                                                 1,
                                             ),
-                                            range: 135..140,
+                                            range: 446..451,
                                         },
                                     ),
                                 ),

src/tools/rust-analyzer/crates/intern/src/symbol/symbols.rs

@@ -438,6 +438,8 @@ define_symbols! {
     shr,
     simd,
     sized,
+    meta_sized,
+    pointee_sized,
     skip,
     slice_len_fn,
     Some,