⬆️ rust-analyzer

Merge commit '368e0bb32f'

crates/hir-ty/src/autoderef.rs

@@ -82,11 +82,11 @@ pub(crate) fn autoderef_step(
 }
 
 // FIXME: replace uses of this with Autoderef above
-pub fn autoderef<'a>(
-    db: &'a dyn HirDatabase,
+pub fn autoderef(
+    db: &dyn HirDatabase,
     env: Arc<TraitEnvironment>,
     ty: Canonical<Ty>,
-) -> impl Iterator<Item = Canonical<Ty>> + 'a {
+) -> impl Iterator<Item = Canonical<Ty>> + '_ {
     let mut table = InferenceTable::new(db, env);
     let ty = table.instantiate_canonical(ty);
     let mut autoderef = Autoderef::new(&mut table, ty);

crates/hir-ty/src/builder.rs

@@ -142,7 +142,7 @@ impl<D> TyBuilder<D> {
         match (a.data(Interner), e) {
             (chalk_ir::GenericArgData::Ty(_), ParamKind::Type)
             | (chalk_ir::GenericArgData::Const(_), ParamKind::Const(_)) => (),
-            _ => panic!("Mismatched kinds: {:?}, {:?}, {:?}", a, self.vec, self.param_kinds),
+            _ => panic!("Mismatched kinds: {a:?}, {:?}, {:?}", self.vec, self.param_kinds),
         }
     }
 }

crates/hir-ty/src/chalk_db.rs

@@ -568,6 +568,7 @@ fn well_known_trait_from_lang_attr(name: &str) -> Option<WellKnownTrait> {
         "sized" => WellKnownTrait::Sized,
         "unpin" => WellKnownTrait::Unpin,
         "unsize" => WellKnownTrait::Unsize,
+        "tuple_trait" => WellKnownTrait::Tuple,
         _ => return None,
     })
 }
@@ -585,6 +586,7 @@ fn lang_attr_from_well_known_trait(attr: WellKnownTrait) -> &'static str {
         WellKnownTrait::FnOnce => "fn_once",
         WellKnownTrait::Generator => "generator",
         WellKnownTrait::Sized => "sized",
+        WellKnownTrait::Tuple => "tuple_trait",
         WellKnownTrait::Unpin => "unpin",
         WellKnownTrait::Unsize => "unsize",
     }

crates/hir-ty/src/consteval.rs

@@ -90,14 +90,14 @@ impl Display for ComputedExpr {
             ComputedExpr::Literal(l) => match l {
                 Literal::Int(x, _) => {
                     if *x >= 10 {
-                        write!(f, "{} ({:#X})", x, x)
+                        write!(f, "{x} ({x:#X})")
                     } else {
                         x.fmt(f)
                     }
                 }
                 Literal::Uint(x, _) => {
                     if *x >= 10 {
-                        write!(f, "{} ({:#X})", x, x)
+                        write!(f, "{x} ({x:#X})")
                     } else {
                         x.fmt(f)
                     }
@@ -131,7 +131,7 @@ fn scalar_max(scalar: &Scalar) -> i128 {
             IntTy::I16 => i16::MAX as i128,
             IntTy::I32 => i32::MAX as i128,
             IntTy::I64 => i64::MAX as i128,
-            IntTy::I128 => i128::MAX as i128,
+            IntTy::I128 => i128::MAX,
         },
         Scalar::Uint(x) => match x {
             chalk_ir::UintTy::Usize => usize::MAX as i128,
@@ -139,7 +139,7 @@ fn scalar_max(scalar: &Scalar) -> i128 {
             chalk_ir::UintTy::U16 => u16::MAX as i128,
             chalk_ir::UintTy::U32 => u32::MAX as i128,
             chalk_ir::UintTy::U64 => u64::MAX as i128,
-            chalk_ir::UintTy::U128 => i128::MAX as i128, // ignore too big u128 for now
+            chalk_ir::UintTy::U128 => i128::MAX, // ignore too big u128 for now
         },
         Scalar::Float(_) => 0,
     }
@@ -351,15 +351,17 @@ pub fn eval_const(
                         .infer
                         .assoc_resolutions_for_expr(expr_id)
                         .ok_or(ConstEvalError::SemanticError("unresolved assoc item"))?
+                        .0
                     {
                         hir_def::AssocItemId::FunctionId(_) => {
                             Err(ConstEvalError::NotSupported("assoc function"))
                         }
+                        // FIXME use actual impl for trait assoc const
                         hir_def::AssocItemId::ConstId(c) => ctx.db.const_eval(c),
                         hir_def::AssocItemId::TypeAliasId(_) => {
                             Err(ConstEvalError::NotSupported("assoc type alias"))
                         }
-                    }
+                    };
                 }
             };
             match pr {
@@ -402,7 +404,7 @@ pub(crate) fn path_to_const(
     args_lazy: impl FnOnce() -> Generics,
     debruijn: DebruijnIndex,
 ) -> Option<Const> {
-    match resolver.resolve_path_in_value_ns_fully(db.upcast(), &path) {
+    match resolver.resolve_path_in_value_ns_fully(db.upcast(), path) {
         Some(ValueNs::GenericParam(p)) => {
             let ty = db.const_param_ty(p);
             let args = args_lazy();
@@ -509,10 +511,10 @@ pub(crate) fn const_eval_query_variant(
     )
 }
 
-pub(crate) fn eval_to_const<'a>(
+pub(crate) fn eval_to_const(
     expr: Idx<Expr>,
     mode: ParamLoweringMode,
-    ctx: &mut InferenceContext<'a>,
+    ctx: &mut InferenceContext<'_>,
     args: impl FnOnce() -> Generics,
     debruijn: DebruijnIndex,
 ) -> Const {

crates/hir-ty/src/consteval/tests.rs

@@ -14,7 +14,7 @@ fn check_number(ra_fixture: &str, answer: i128) {
     match r {
         ComputedExpr::Literal(Literal::Int(r, _)) => assert_eq!(r, answer),
         ComputedExpr::Literal(Literal::Uint(r, _)) => assert_eq!(r, answer as u128),
-        x => panic!("Expected number but found {:?}", x),
+        x => panic!("Expected number but found {x:?}"),
     }
 }
 
@@ -25,7 +25,6 @@ fn eval_goal(ra_fixture: &str) -> Result<ComputedExpr, ConstEvalError> {
     let scope = &def_map[module_id.local_id].scope;
     let const_id = scope
         .declarations()
-        .into_iter()
         .find_map(|x| match x {
             hir_def::ModuleDefId::ConstId(x) => {
                 if db.const_data(x).name.as_ref()?.to_string() == "GOAL" {
@@ -126,7 +125,7 @@ fn enums() {
             assert_eq!(name, "E::A");
             assert_eq!(val, 1);
         }
-        x => panic!("Expected enum but found {:?}", x),
+        x => panic!("Expected enum but found {x:?}"),
     }
 }
 

crates/hir-ty/src/db.rs

@@ -3,20 +3,23 @@
 
 use std::sync::Arc;
 
-use arrayvec::ArrayVec;
 use base_db::{impl_intern_key, salsa, CrateId, Upcast};
 use hir_def::{
-    db::DefDatabase, expr::ExprId, BlockId, ConstId, ConstParamId, DefWithBodyId, EnumVariantId,
-    FunctionId, GenericDefId, ImplId, LifetimeParamId, LocalFieldId, TypeOrConstParamId, VariantId,
+    db::DefDatabase,
+    expr::ExprId,
+    layout::{Layout, LayoutError, TargetDataLayout},
+    AdtId, BlockId, ConstId, ConstParamId, DefWithBodyId, EnumVariantId, FunctionId, GenericDefId,
+    ImplId, LifetimeParamId, LocalFieldId, TypeOrConstParamId, VariantId,
 };
 use la_arena::ArenaMap;
+use smallvec::SmallVec;
 
 use crate::{
     chalk_db,
     consteval::{ComputedExpr, ConstEvalError},
     method_resolution::{InherentImpls, TraitImpls, TyFingerprint},
     Binders, CallableDefId, FnDefId, GenericArg, ImplTraitId, InferenceResult, Interner, PolyFnSig,
-    QuantifiedWhereClause, ReturnTypeImplTraits, TraitRef, Ty, TyDefId, ValueTyDefId,
+    QuantifiedWhereClause, ReturnTypeImplTraits, Substitution, TraitRef, Ty, TyDefId, ValueTyDefId,
 };
 use hir_expand::name::Name;
 
@@ -57,6 +60,13 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::invoke(crate::lower::field_types_query)]
     fn field_types(&self, var: VariantId) -> Arc<ArenaMap<LocalFieldId, Binders<Ty>>>;
 
+    #[salsa::invoke(crate::layout::layout_of_adt_query)]
+    #[salsa::cycle(crate::layout::layout_of_adt_recover)]
+    fn layout_of_adt(&self, def: AdtId, subst: Substitution) -> Result<Layout, LayoutError>;
+
+    #[salsa::invoke(crate::layout::target_data_layout_query)]
+    fn target_data_layout(&self, krate: CrateId) -> Arc<TargetDataLayout>;
+
     #[salsa::invoke(crate::lower::callable_item_sig)]
     fn callable_item_signature(&self, def: CallableDefId) -> PolyFnSig;
 
@@ -92,10 +102,15 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn inherent_impls_in_block(&self, block: BlockId) -> Option<Arc<InherentImpls>>;
 
     /// Collects all crates in the dependency graph that have impls for the
-    /// given fingerprint. This is only used for primitive types; for
-    /// user-defined types we just look at the crate where the type is defined.
-    #[salsa::invoke(crate::method_resolution::inherent_impl_crates_query)]
-    fn inherent_impl_crates(&self, krate: CrateId, fp: TyFingerprint) -> ArrayVec<CrateId, 2>;
+    /// given fingerprint. This is only used for primitive types and types
+    /// annotated with `rustc_has_incoherent_inherent_impls`; for other types
+    /// we just look at the crate where the type is defined.
+    #[salsa::invoke(crate::method_resolution::incoherent_inherent_impl_crates)]
+    fn incoherent_inherent_impl_crates(
+        &self,
+        krate: CrateId,
+        fp: TyFingerprint,
+    ) -> SmallVec<[CrateId; 2]>;
 
     #[salsa::invoke(TraitImpls::trait_impls_in_crate_query)]
     fn trait_impls_in_crate(&self, krate: CrateId) -> Arc<TraitImpls>;

crates/hir-ty/src/diagnostics/match_check.rs

@@ -12,16 +12,16 @@ pub(crate) mod usefulness;
 
 use chalk_ir::Mutability;
 use hir_def::{
-    adt::VariantData, body::Body, expr::PatId, AdtId, EnumVariantId, HasModule, LocalFieldId,
-    VariantId,
+    adt::VariantData, body::Body, expr::PatId, AdtId, EnumVariantId, LocalFieldId, VariantId,
 };
-use hir_expand::name::{name, Name};
+use hir_expand::name::Name;
 use stdx::{always, never};
 
 use crate::{
     db::HirDatabase,
     display::{HirDisplay, HirDisplayError, HirFormatter},
     infer::BindingMode,
+    lang_items::is_box,
     InferenceResult, Interner, Substitution, Ty, TyExt, TyKind,
 };
 
@@ -386,7 +386,7 @@ impl HirDisplay for Pat {
                 }
                 subpattern.hir_fmt(f)
             }
-            PatKind::LiteralBool { value } => write!(f, "{}", value),
+            PatKind::LiteralBool { value } => write!(f, "{value}"),
             PatKind::Or { pats } => f.write_joined(pats.iter(), " | "),
         }
     }
@@ -405,13 +405,6 @@ where
     }
 }
 
-fn is_box(adt: AdtId, db: &dyn HirDatabase) -> bool {
-    let owned_box = name![owned_box].to_smol_str();
-    let krate = adt.module(db.upcast()).krate();
-    let box_adt = db.lang_item(krate, owned_box).and_then(|it| it.as_struct()).map(AdtId::from);
-    Some(adt) == box_adt
-}
-
 pub(crate) trait PatternFoldable: Sized {
     fn fold_with<F: PatternFolder>(&self, folder: &mut F) -> Self {
         self.super_fold_with(folder)

crates/hir-ty/src/diagnostics/match_check/deconstruct_pat.rs

@@ -372,7 +372,7 @@ impl Constructor {
                     hir_def::AdtId::UnionId(id) => id.into(),
                 }
             }
-            _ => panic!("bad constructor {:?} for adt {:?}", self, adt),
+            _ => panic!("bad constructor {self:?} for adt {adt:?}"),
         }
     }
 

crates/hir-ty/src/display.rs

@@ -16,7 +16,7 @@ use hir_def::{
     path::{Path, PathKind},
     type_ref::{ConstScalar, TraitBoundModifier, TypeBound, TypeRef},
     visibility::Visibility,
-    HasModule, ItemContainerId, Lookup, ModuleId, TraitId,
+    HasModule, ItemContainerId, Lookup, ModuleDefId, ModuleId, TraitId,
 };
 use hir_expand::{hygiene::Hygiene, name::Name};
 use itertools::Itertools;
@@ -35,9 +35,27 @@ use crate::{
     TraitRefExt, Ty, TyExt, TyKind, WhereClause,
 };
 
+pub trait HirWrite: fmt::Write {
+    fn start_location_link(&mut self, location: ModuleDefId);
+    fn end_location_link(&mut self);
+}
+
+// String will ignore link metadata
+impl HirWrite for String {
+    fn start_location_link(&mut self, _: ModuleDefId) {}
+
+    fn end_location_link(&mut self) {}
+}
+
+// `core::Formatter` will ignore metadata
+impl HirWrite for fmt::Formatter<'_> {
+    fn start_location_link(&mut self, _: ModuleDefId) {}
+    fn end_location_link(&mut self) {}
+}
+
 pub struct HirFormatter<'a> {
     pub db: &'a dyn HirDatabase,
-    fmt: &'a mut dyn fmt::Write,
+    fmt: &'a mut dyn HirWrite,
     buf: String,
     curr_size: usize,
     pub(crate) max_size: Option<usize>,
@@ -45,6 +63,16 @@ pub struct HirFormatter<'a> {
     display_target: DisplayTarget,
 }
 
+impl HirFormatter<'_> {
+    fn start_location_link(&mut self, location: ModuleDefId) {
+        self.fmt.start_location_link(location);
+    }
+
+    fn end_location_link(&mut self) {
+        self.fmt.end_location_link();
+    }
+}
+
 pub trait HirDisplay {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError>;
 
@@ -148,13 +176,13 @@ impl<'a> HirFormatter<'a> {
         let mut first = true;
         for e in iter {
             if !first {
-                write!(self, "{}", sep)?;
+                write!(self, "{sep}")?;
             }
             first = false;
 
             // Abbreviate multiple omitted types with a single ellipsis.
             if self.should_truncate() {
-                return write!(self, "{}", TYPE_HINT_TRUNCATION);
+                return write!(self, "{TYPE_HINT_TRUNCATION}");
             }
 
             e.hir_fmt(self)?;
@@ -245,12 +273,9 @@ pub struct HirDisplayWrapper<'a, T> {
     display_target: DisplayTarget,
 }
 
-impl<'a, T> fmt::Display for HirDisplayWrapper<'a, T>
-where
-    T: HirDisplay,
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self.t.hir_fmt(&mut HirFormatter {
+impl<T: HirDisplay> HirDisplayWrapper<'_, T> {
+    pub fn write_to<F: HirWrite>(&self, f: &mut F) -> Result<(), HirDisplayError> {
+        self.t.hir_fmt(&mut HirFormatter {
             db: self.db,
             fmt: f,
             buf: String::with_capacity(20),
@@ -258,7 +283,16 @@ where
             max_size: self.max_size,
             omit_verbose_types: self.omit_verbose_types,
             display_target: self.display_target,
-        }) {
+        })
+    }
+}
+
+impl<'a, T> fmt::Display for HirDisplayWrapper<'a, T>
+where
+    T: HirDisplay,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.write_to(f) {
             Ok(()) => Ok(()),
             Err(HirDisplayError::FmtError) => Err(fmt::Error),
             Err(HirDisplayError::DisplaySourceCodeError(_)) => {
@@ -286,7 +320,7 @@ impl<T: HirDisplay + Internable> HirDisplay for Interned<T> {
 impl HirDisplay for ProjectionTy {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+            return write!(f, "{TYPE_HINT_TRUNCATION}");
         }
 
         let trait_ref = self.trait_ref(f.db);
@@ -308,7 +342,7 @@ impl HirDisplay for ProjectionTy {
 impl HirDisplay for OpaqueTy {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+            return write!(f, "{TYPE_HINT_TRUNCATION}");
         }
 
         self.substitution.at(Interner, 0).hir_fmt(f)
@@ -351,7 +385,7 @@ impl HirDisplay for BoundVar {
 impl HirDisplay for Ty {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+            return write!(f, "{TYPE_HINT_TRUNCATION}");
         }
 
         match self.kind(Interner) {
@@ -530,6 +564,7 @@ impl HirDisplay for Ty {
                 }
             }
             TyKind::Adt(AdtId(def_id), parameters) => {
+                f.start_location_link((*def_id).into());
                 match f.display_target {
                     DisplayTarget::Diagnostics | DisplayTarget::Test => {
                         let name = match *def_id {
@@ -537,7 +572,7 @@ impl HirDisplay for Ty {
                             hir_def::AdtId::UnionId(it) => f.db.union_data(it).name.clone(),
                             hir_def::AdtId::EnumId(it) => f.db.enum_data(it).name.clone(),
                         };
-                        write!(f, "{}", name)?;
+                        write!(f, "{name}")?;
                     }
                     DisplayTarget::SourceCode { module_id } => {
                         if let Some(path) = find_path::find_path(
@@ -546,7 +581,7 @@ impl HirDisplay for Ty {
                             module_id,
                             false,
                         ) {
-                            write!(f, "{}", path)?;
+                            write!(f, "{path}")?;
                         } else {
                             return Err(HirDisplayError::DisplaySourceCodeError(
                                 DisplaySourceCodeError::PathNotFound,
@@ -554,6 +589,7 @@ impl HirDisplay for Ty {
                         }
                     }
                 }
+                f.end_location_link();
 
                 if parameters.len(Interner) > 0 {
                     let parameters_to_write = if f.display_target.is_source_code()
@@ -701,7 +737,7 @@ impl HirDisplay for Ty {
                     if sig.params().is_empty() {
                         write!(f, "||")?;
                     } else if f.should_truncate() {
-                        write!(f, "|{}|", TYPE_HINT_TRUNCATION)?;
+                        write!(f, "|{TYPE_HINT_TRUNCATION}|")?;
                     } else {
                         write!(f, "|")?;
                         f.write_joined(sig.params(), ", ")?;
@@ -892,7 +928,7 @@ pub fn write_bounds_like_dyn_trait_with_prefix(
     default_sized: SizedByDefault,
     f: &mut HirFormatter<'_>,
 ) -> Result<(), HirDisplayError> {
-    write!(f, "{}", prefix)?;
+    write!(f, "{prefix}")?;
     if !predicates.is_empty()
         || predicates.is_empty() && matches!(default_sized, SizedByDefault::Sized { .. })
     {
@@ -1020,7 +1056,7 @@ fn fmt_trait_ref(
     use_as: bool,
 ) -> Result<(), HirDisplayError> {
     if f.should_truncate() {
-        return write!(f, "{}", TYPE_HINT_TRUNCATION);
+        return write!(f, "{TYPE_HINT_TRUNCATION}");
     }
 
     tr.self_type_parameter(Interner).hir_fmt(f)?;
@@ -1047,7 +1083,7 @@ impl HirDisplay for TraitRef {
 impl HirDisplay for WhereClause {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+            return write!(f, "{TYPE_HINT_TRUNCATION}");
         }
 
         match self {
@@ -1098,7 +1134,6 @@ impl HirDisplay for LifetimeData {
                 write!(f, "{}", param_data.name)
             }
             LifetimeData::Static => write!(f, "'static"),
-            LifetimeData::Empty(_) => Ok(()),
             LifetimeData::Erased => Ok(()),
             LifetimeData::Phantom(_, _) => Ok(()),
         }
@@ -1162,7 +1197,7 @@ impl HirDisplay for TypeRef {
                     hir_def::type_ref::Mutability::Shared => "*const ",
                     hir_def::type_ref::Mutability::Mut => "*mut ",
                 };
-                write!(f, "{}", mutability)?;
+                write!(f, "{mutability}")?;
                 inner.hir_fmt(f)?;
             }
             TypeRef::Reference(inner, lifetime, mutability) => {
@@ -1174,13 +1209,13 @@ impl HirDisplay for TypeRef {
                 if let Some(lifetime) = lifetime {
                     write!(f, "{} ", lifetime.name)?;
                 }
-                write!(f, "{}", mutability)?;
+                write!(f, "{mutability}")?;
                 inner.hir_fmt(f)?;
             }
             TypeRef::Array(inner, len) => {
                 write!(f, "[")?;
                 inner.hir_fmt(f)?;
-                write!(f, "; {}]", len)?;
+                write!(f, "; {len}]")?;
             }
             TypeRef::Slice(inner) => {
                 write!(f, "[")?;
@@ -1197,7 +1232,7 @@ impl HirDisplay for TypeRef {
                     for index in 0..function_parameters.len() {
                         let (param_name, param_type) = &function_parameters[index];
                         if let Some(name) = param_name {
-                            write!(f, "{}: ", name)?;
+                            write!(f, "{name}: ")?;
                         }
 
                         param_type.hir_fmt(f)?;
@@ -1373,7 +1408,7 @@ impl HirDisplay for hir_def::path::GenericArg {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
         match self {
             hir_def::path::GenericArg::Type(ty) => ty.hir_fmt(f),
-            hir_def::path::GenericArg::Const(c) => write!(f, "{}", c),
+            hir_def::path::GenericArg::Const(c) => write!(f, "{c}"),
             hir_def::path::GenericArg::Lifetime(lifetime) => write!(f, "{}", lifetime.name),
         }
     }

crates/hir-ty/src/infer.rs

@@ -19,10 +19,11 @@ use std::sync::Arc;
 use chalk_ir::{cast::Cast, ConstValue, DebruijnIndex, Mutability, Safety, Scalar, TypeFlags};
 use hir_def::{
     body::Body,
-    builtin_type::BuiltinType,
+    builtin_type::{BuiltinInt, BuiltinType, BuiltinUint},
     data::{ConstData, StaticData},
-    expr::{BindingAnnotation, ExprId, PatId},
+    expr::{BindingAnnotation, ExprId, ExprOrPatId, PatId},
     lang_item::LangItemTarget,
+    layout::Integer,
     path::{path, Path},
     resolver::{HasResolver, ResolveValueResult, Resolver, TypeNs, ValueNs},
     type_ref::TypeRef,
@@ -33,7 +34,7 @@ use hir_expand::name::{name, Name};
 use itertools::Either;
 use la_arena::ArenaMap;
 use rustc_hash::FxHashMap;
-use stdx::{always, impl_from};
+use stdx::always;
 
 use crate::{
     db::HirDatabase, fold_tys, fold_tys_and_consts, infer::coerce::CoerceMany,
@@ -70,8 +71,26 @@ pub(crate) fn infer_query(db: &dyn HirDatabase, def: DefWithBodyId) -> Arc<Infer
         DefWithBodyId::StaticId(s) => ctx.collect_static(&db.static_data(s)),
         DefWithBodyId::VariantId(v) => {
             ctx.return_ty = TyBuilder::builtin(match db.enum_data(v.parent).variant_body_type() {
-                Either::Left(builtin) => BuiltinType::Int(builtin),
-                Either::Right(builtin) => BuiltinType::Uint(builtin),
+                hir_def::layout::IntegerType::Pointer(signed) => match signed {
+                    true => BuiltinType::Int(BuiltinInt::Isize),
+                    false => BuiltinType::Uint(BuiltinUint::Usize),
+                },
+                hir_def::layout::IntegerType::Fixed(size, signed) => match signed {
+                    true => BuiltinType::Int(match size {
+                        Integer::I8 => BuiltinInt::I8,
+                        Integer::I16 => BuiltinInt::I16,
+                        Integer::I32 => BuiltinInt::I32,
+                        Integer::I64 => BuiltinInt::I64,
+                        Integer::I128 => BuiltinInt::I128,
+                    }),
+                    false => BuiltinType::Uint(match size {
+                        Integer::I8 => BuiltinUint::U8,
+                        Integer::I16 => BuiltinUint::U16,
+                        Integer::I32 => BuiltinUint::U32,
+                        Integer::I64 => BuiltinUint::U64,
+                        Integer::I128 => BuiltinUint::U128,
+                    }),
+                },
             });
         }
     }
@@ -101,13 +120,6 @@ pub(crate) fn normalize(db: &dyn HirDatabase, owner: DefWithBodyId, ty: Ty) -> T
     table.resolve_completely(ty_with_vars)
 }
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
-enum ExprOrPatId {
-    ExprId(ExprId),
-    PatId(PatId),
-}
-impl_from!(ExprId, PatId for ExprOrPatId);
-
 /// Binding modes inferred for patterns.
 /// <https://doc.rust-lang.org/reference/patterns.html#binding-modes>
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
@@ -189,6 +201,8 @@ pub(crate) type InferResult<T> = Result<InferOk<T>, TypeError>;
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum InferenceDiagnostic {
     NoSuchField { expr: ExprId },
+    PrivateField { expr: ExprId, field: FieldId },
+    PrivateAssocItem { id: ExprOrPatId, item: AssocItemId },
     BreakOutsideOfLoop { expr: ExprId, is_break: bool },
     MismatchedArgCount { call_expr: ExprId, expected: usize, found: usize },
 }
@@ -330,7 +344,7 @@ pub struct InferenceResult {
     /// For each struct literal or pattern, records the variant it resolves to.
     variant_resolutions: FxHashMap<ExprOrPatId, VariantId>,
     /// For each associated item record what it resolves to
-    assoc_resolutions: FxHashMap<ExprOrPatId, AssocItemId>,
+    assoc_resolutions: FxHashMap<ExprOrPatId, (AssocItemId, Substitution)>,
     pub diagnostics: Vec<InferenceDiagnostic>,
     pub type_of_expr: ArenaMap<ExprId, Ty>,
     /// For each pattern record the type it resolves to.
@@ -360,11 +374,11 @@ impl InferenceResult {
     pub fn variant_resolution_for_pat(&self, id: PatId) -> Option<VariantId> {
         self.variant_resolutions.get(&id.into()).copied()
     }
-    pub fn assoc_resolutions_for_expr(&self, id: ExprId) -> Option<AssocItemId> {
-        self.assoc_resolutions.get(&id.into()).copied()
+    pub fn assoc_resolutions_for_expr(&self, id: ExprId) -> Option<(AssocItemId, Substitution)> {
+        self.assoc_resolutions.get(&id.into()).cloned()
     }
-    pub fn assoc_resolutions_for_pat(&self, id: PatId) -> Option<AssocItemId> {
-        self.assoc_resolutions.get(&id.into()).copied()
+    pub fn assoc_resolutions_for_pat(&self, id: PatId) -> Option<(AssocItemId, Substitution)> {
+        self.assoc_resolutions.get(&id.into()).cloned()
     }
     pub fn type_mismatch_for_expr(&self, expr: ExprId) -> Option<&TypeMismatch> {
         self.type_mismatches.get(&expr.into())
@@ -484,7 +498,7 @@ impl<'a> InferenceContext<'a> {
             result: InferenceResult::default(),
             table: unify::InferenceTable::new(db, trait_env.clone()),
             trait_env,
-            return_ty: TyKind::Error.intern(Interner), // set in collect_fn_signature
+            return_ty: TyKind::Error.intern(Interner), // set in collect_* calls
             resume_yield_tys: None,
             db,
             owner,
@@ -498,6 +512,8 @@ impl<'a> InferenceContext<'a> {
     fn resolve_all(self) -> InferenceResult {
         let InferenceContext { mut table, mut result, .. } = self;
 
+        table.fallback_if_possible();
+
         // FIXME resolve obligations as well (use Guidance if necessary)
         table.resolve_obligations_as_possible();
 
@@ -516,6 +532,9 @@ impl<'a> InferenceContext<'a> {
         for (_, subst) in result.method_resolutions.values_mut() {
             *subst = table.resolve_completely(subst.clone());
         }
+        for (_, subst) in result.assoc_resolutions.values_mut() {
+            *subst = table.resolve_completely(subst.clone());
+        }
         for adjustment in result.expr_adjustments.values_mut().flatten() {
             adjustment.target = table.resolve_completely(adjustment.target.clone());
         }
@@ -537,8 +556,20 @@ impl<'a> InferenceContext<'a> {
         let data = self.db.function_data(func);
         let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver)
             .with_impl_trait_mode(ImplTraitLoweringMode::Param);
-        let param_tys =
+        let mut param_tys =
             data.params.iter().map(|(_, type_ref)| ctx.lower_ty(type_ref)).collect::<Vec<_>>();
+        // Check if function contains a va_list, if it does then we append it to the parameter types
+        // that are collected from the function data
+        if data.is_varargs() {
+            let va_list_ty = match self.resolve_va_list() {
+                Some(va_list) => TyBuilder::adt(self.db, va_list)
+                    .fill_with_defaults(self.db, || self.table.new_type_var())
+                    .build(),
+                None => self.err_ty(),
+            };
+
+            param_tys.push(va_list_ty)
+        }
         for (ty, pat) in param_tys.into_iter().zip(self.body.params.iter()) {
             let ty = self.insert_type_vars(ty);
             let ty = self.normalize_associated_types_in(ty);
@@ -551,14 +582,17 @@ impl<'a> InferenceContext<'a> {
         } else {
             &*data.ret_type
         };
-        let return_ty = self.make_ty_with_mode(return_ty, ImplTraitLoweringMode::Opaque);
-        self.return_ty = return_ty;
 
-        if let Some(rpits) = self.db.return_type_impl_traits(func) {
+        let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver)
+            .with_impl_trait_mode(ImplTraitLoweringMode::Opaque);
+        let return_ty = ctx.lower_ty(return_ty);
+        let return_ty = self.insert_type_vars(return_ty);
+
+        let return_ty = if let Some(rpits) = self.db.return_type_impl_traits(func) {
             // RPIT opaque types use substitution of their parent function.
             let fn_placeholders = TyBuilder::placeholder_subst(self.db, func);
-            self.return_ty = fold_tys(
-                self.return_ty.clone(),
+            fold_tys(
+                return_ty,
                 |ty, _| {
                     let opaque_ty_id = match ty.kind(Interner) {
                         TyKind::OpaqueType(opaque_ty_id, _) => *opaque_ty_id,
@@ -579,14 +613,18 @@ impl<'a> InferenceContext<'a> {
                         let (var_predicate, binders) = predicate
                             .substitute(Interner, &var_subst)
                             .into_value_and_skipped_binders();
-                        always!(binders.len(Interner) == 0); // quantified where clauses not yet handled
+                        always!(binders.is_empty(Interner)); // quantified where clauses not yet handled
                         self.push_obligation(var_predicate.cast(Interner));
                     }
                     var
                 },
                 DebruijnIndex::INNERMOST,
-            );
-        }
+            )
+        } else {
+            return_ty
+        };
+
+        self.return_ty = self.normalize_associated_types_in(return_ty);
     }
 
     fn infer_body(&mut self) {
@@ -609,8 +647,8 @@ impl<'a> InferenceContext<'a> {
         self.result.variant_resolutions.insert(id, variant);
     }
 
-    fn write_assoc_resolution(&mut self, id: ExprOrPatId, item: AssocItemId) {
-        self.result.assoc_resolutions.insert(id, item);
+    fn write_assoc_resolution(&mut self, id: ExprOrPatId, item: AssocItemId, subs: Substitution) {
+        self.result.assoc_resolutions.insert(id, (item, subs));
     }
 
     fn write_pat_ty(&mut self, pat: PatId, ty: Ty) {
@@ -621,23 +659,14 @@ impl<'a> InferenceContext<'a> {
         self.result.diagnostics.push(diagnostic);
     }
 
-    fn make_ty_with_mode(
-        &mut self,
-        type_ref: &TypeRef,
-        impl_trait_mode: ImplTraitLoweringMode,
-    ) -> Ty {
+    fn make_ty(&mut self, type_ref: &TypeRef) -> Ty {
         // FIXME use right resolver for block
-        let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver)
-            .with_impl_trait_mode(impl_trait_mode);
+        let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver);
         let ty = ctx.lower_ty(type_ref);
         let ty = self.insert_type_vars(ty);
         self.normalize_associated_types_in(ty)
     }
 
-    fn make_ty(&mut self, type_ref: &TypeRef) -> Ty {
-        self.make_ty_with_mode(type_ref, ImplTraitLoweringMode::Disallowed)
-    }
-
     fn err_ty(&self) -> Ty {
         self.result.standard_types.unknown.clone()
     }
@@ -656,7 +685,7 @@ impl<'a> InferenceContext<'a> {
         }
     }
 
-    /// Replaces Ty::Unknown by a new type var, so we can maybe still infer it.
+    /// Replaces `Ty::Error` by a new type var, so we can maybe still infer it.
     fn insert_type_vars_shallow(&mut self, ty: Ty) -> Ty {
         match ty.kind(Interner) {
             TyKind::Error => self.table.new_type_var(),
@@ -983,6 +1012,11 @@ impl<'a> InferenceContext<'a> {
         let trait_ = self.resolve_ops_index()?;
         self.db.trait_data(trait_).associated_type_by_name(&name![Output])
     }
+
+    fn resolve_va_list(&self) -> Option<AdtId> {
+        let struct_ = self.resolve_lang_item(name![va_list])?.as_struct()?;
+        Some(struct_.into())
+    }
 }
 
 /// When inferring an expression, we propagate downward whatever type hint we

crates/hir-ty/src/infer/expr.rs

@@ -1,13 +1,12 @@
 //! Type inference for expressions.
 
 use std::{
-    collections::hash_map::Entry,
     iter::{repeat, repeat_with},
     mem,
 };
 
 use chalk_ir::{
-    cast::Cast, fold::Shift, DebruijnIndex, GenericArgData, Mutability, TyVariableKind,
+    cast::Cast, fold::Shift, DebruijnIndex, GenericArgData, Mutability, TyKind, TyVariableKind,
 };
 use hir_def::{
     expr::{
@@ -35,8 +34,8 @@ use crate::{
     primitive::{self, UintTy},
     static_lifetime, to_chalk_trait_id,
     utils::{generics, Generics},
-    AdtId, Binders, CallableDefId, FnPointer, FnSig, FnSubst, Interner, Rawness, Scalar,
-    Substitution, TraitRef, Ty, TyBuilder, TyExt, TyKind,
+    Adjust, Adjustment, AdtId, AutoBorrow, Binders, CallableDefId, FnPointer, FnSig, FnSubst,
+    Interner, Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyExt,
 };
 
 use super::{
@@ -152,11 +151,20 @@ impl<'a> InferenceContext<'a> {
                 .1
             }
             Expr::TryBlock { body } => {
-                self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
-                    let _inner = this.infer_expr(*body, expected);
+                // The type that is returned from the try block
+                let try_ty = self.table.new_type_var();
+                if let Some(ty) = expected.only_has_type(&mut self.table) {
+                    self.unify(&try_ty, &ty);
+                }
+
+                // The ok-ish type that is expected from the last expression
+                let ok_ty = self.resolve_associated_type(try_ty.clone(), self.resolve_ops_try_ok());
+
+                self.with_breakable_ctx(BreakableKind::Block, ok_ty.clone(), None, |this| {
+                    this.infer_expr(*body, &Expectation::has_type(ok_ty));
                 });
-                // FIXME should be std::result::Result<{inner}, _>
-                self.err_ty()
+
+                try_ty
             }
             Expr::Async { body } => {
                 let ret_ty = self.table.new_type_var();
@@ -326,6 +334,7 @@ impl<'a> InferenceContext<'a> {
                 let (param_tys, ret_ty) = match res {
                     Some(res) => {
                         let adjustments = auto_deref_adjust_steps(&derefs);
+                        // FIXME: Handle call adjustments for Fn/FnMut
                         self.write_expr_adj(*callee, adjustments);
                         res
                     }
@@ -465,6 +474,12 @@ impl<'a> InferenceContext<'a> {
                     TyKind::Error.intern(Interner)
                 }
             }
+            Expr::Yeet { expr } => {
+                if let &Some(expr) = expr {
+                    self.infer_expr_inner(expr, &Expectation::None);
+                }
+                TyKind::Never.intern(Interner)
+            }
             Expr::RecordLit { path, fields, spread, .. } => {
                 let (ty, def_id) = self.resolve_variant(path.as_deref(), false);
                 if let Some(variant) = def_id {
@@ -506,6 +521,7 @@ impl<'a> InferenceContext<'a> {
                 let receiver_ty = self.infer_expr_inner(*expr, &Expectation::none());
 
                 let mut autoderef = Autoderef::new(&mut self.table, receiver_ty);
+                let mut private_field = None;
                 let ty = autoderef.by_ref().find_map(|(derefed_ty, _)| {
                     let (field_id, parameters) = match derefed_ty.kind(Interner) {
                         TyKind::Tuple(_, substs) => {
@@ -532,13 +548,8 @@ impl<'a> InferenceContext<'a> {
                     let is_visible = self.db.field_visibilities(field_id.parent)[field_id.local_id]
                         .is_visible_from(self.db.upcast(), self.resolver.module());
                     if !is_visible {
-                        // Write down the first field resolution even if it is not visible
-                        // This aids IDE features for private fields like goto def and in
-                        // case of autoderef finding an applicable field, this will be
-                        // overwritten in a following cycle
-                        if let Entry::Vacant(entry) = self.result.field_resolutions.entry(tgt_expr)
-                        {
-                            entry.insert(field_id);
+                        if private_field.is_none() {
+                            private_field = Some(field_id);
                         }
                         return None;
                     }
@@ -557,7 +568,17 @@ impl<'a> InferenceContext<'a> {
                         let ty = self.normalize_associated_types_in(ty);
                         ty
                     }
-                    _ => self.err_ty(),
+                    _ => {
+                        // Write down the first private field resolution if we found no field
+                        // This aids IDE features for private fields like goto def
+                        if let Some(field) = private_field {
+                            self.result.field_resolutions.insert(tgt_expr, field);
+                            self.result
+                                .diagnostics
+                                .push(InferenceDiagnostic::PrivateField { expr: tgt_expr, field });
+                        }
+                        self.err_ty()
+                    }
                 };
                 ty
             }
@@ -940,7 +961,7 @@ impl<'a> InferenceContext<'a> {
             Expr::RecordLit { path, fields, .. } => {
                 let subs = fields.iter().map(|f| (f.name.clone(), f.expr));
 
-                self.infer_record_pat_like(path.as_deref(), &rhs_ty, (), lhs.into(), subs)
+                self.infer_record_pat_like(path.as_deref(), &rhs_ty, (), lhs, subs)
             }
             Expr::Underscore => rhs_ty.clone(),
             _ => {
@@ -1018,14 +1039,38 @@ impl<'a> InferenceContext<'a> {
         self.infer_expr_coerce(rhs, &Expectation::has_type(rhs_ty.clone()));
 
         let ret_ty = match method_ty.callable_sig(self.db) {
-            Some(sig) => sig.ret().clone(),
+            Some(sig) => {
+                let p_left = &sig.params()[0];
+                if matches!(op, BinaryOp::CmpOp(..) | BinaryOp::Assignment { .. }) {
+                    if let &TyKind::Ref(mtbl, _, _) = p_left.kind(Interner) {
+                        self.write_expr_adj(
+                            lhs,
+                            vec![Adjustment {
+                                kind: Adjust::Borrow(AutoBorrow::Ref(mtbl)),
+                                target: p_left.clone(),
+                            }],
+                        );
+                    }
+                }
+                let p_right = &sig.params()[1];
+                if matches!(op, BinaryOp::CmpOp(..)) {
+                    if let &TyKind::Ref(mtbl, _, _) = p_right.kind(Interner) {
+                        self.write_expr_adj(
+                            rhs,
+                            vec![Adjustment {
+                                kind: Adjust::Borrow(AutoBorrow::Ref(mtbl)),
+                                target: p_right.clone(),
+                            }],
+                        );
+                    }
+                }
+                sig.ret().clone()
+            }
             None => self.err_ty(),
         };
 
         let ret_ty = self.normalize_associated_types_in(ret_ty);
 
-        // FIXME: record autoref adjustments
-
         // use knowledge of built-in binary ops, which can sometimes help inference
         if let Some(builtin_rhs) = self.builtin_binary_op_rhs_expectation(op, lhs_ty.clone()) {
             self.unify(&builtin_rhs, &rhs_ty);
@@ -1122,20 +1167,26 @@ impl<'a> InferenceContext<'a> {
         let traits_in_scope = self.resolver.traits_in_scope(self.db.upcast());
 
         let resolved = method_resolution::lookup_method(
-            &canonicalized_receiver.value,
             self.db,
+            &canonicalized_receiver.value,
             self.trait_env.clone(),
             &traits_in_scope,
             VisibleFromModule::Filter(self.resolver.module()),
             method_name,
         );
         let (receiver_ty, method_ty, substs) = match resolved {
-            Some((adjust, func)) => {
+            Some((adjust, func, visible)) => {
                 let (ty, adjustments) = adjust.apply(&mut self.table, receiver_ty);
                 let generics = generics(self.db.upcast(), func.into());
                 let substs = self.substs_for_method_call(generics, generic_args);
                 self.write_expr_adj(receiver, adjustments);
                 self.write_method_resolution(tgt_expr, func, substs.clone());
+                if !visible {
+                    self.push_diagnostic(InferenceDiagnostic::PrivateAssocItem {
+                        id: tgt_expr.into(),
+                        item: func.into(),
+                    })
+                }
                 (ty, self.db.value_ty(func.into()), substs)
             }
             None => (
@@ -1309,7 +1360,7 @@ impl<'a> InferenceContext<'a> {
                             ty,
                             c,
                             ParamLoweringMode::Placeholder,
-                            || generics(this.db.upcast(), (&this.resolver).generic_def().unwrap()),
+                            || generics(this.db.upcast(), this.resolver.generic_def().unwrap()),
                             DebruijnIndex::INNERMOST,
                         )
                     },

crates/hir-ty/src/infer/pat.rs

@@ -153,7 +153,7 @@ impl<'a> InferenceContext<'a> {
     ) -> Ty {
         let mut expected = self.resolve_ty_shallow(expected);
 
-        if is_non_ref_pat(&self.body, pat) {
+        if is_non_ref_pat(self.body, pat) {
             let mut pat_adjustments = Vec::new();
             while let Some((inner, _lifetime, mutability)) = expected.as_reference() {
                 pat_adjustments.push(expected.clone());
@@ -220,7 +220,7 @@ impl<'a> InferenceContext<'a> {
                 ),
             Pat::Record { path: p, args: fields, ellipsis: _ } => {
                 let subs = fields.iter().map(|f| (f.name.clone(), f.pat));
-                self.infer_record_pat_like(p.as_deref(), &expected, default_bm, pat.into(), subs)
+                self.infer_record_pat_like(p.as_deref(), &expected, default_bm, pat, subs)
             }
             Pat::Path(path) => {
                 // FIXME use correct resolver for the surrounding expression

crates/hir-ty/src/infer/path.rs

@@ -7,13 +7,15 @@ use hir_def::{
     AdtId, AssocItemId, EnumVariantId, ItemContainerId, Lookup,
 };
 use hir_expand::name::Name;
+use stdx::never;
 
 use crate::{
     builder::ParamKind,
     consteval,
     method_resolution::{self, VisibleFromModule},
     utils::generics,
-    Interner, Substitution, TraitRefExt, Ty, TyBuilder, TyExt, TyKind, ValueTyDefId,
+    InferenceDiagnostic, Interner, Substitution, TraitRefExt, Ty, TyBuilder, TyExt, TyKind,
+    ValueTyDefId,
 };
 
 use super::{ExprOrPatId, InferenceContext, TraitRef};
@@ -212,7 +214,7 @@ impl<'a> InferenceContext<'a> {
             AssocItemId::TypeAliasId(_) => unreachable!(),
         };
 
-        self.write_assoc_resolution(id, item);
+        self.write_assoc_resolution(id, item, trait_ref.substitution.clone());
         Some((def, Some(trait_ref.substitution)))
     }
 
@@ -233,7 +235,8 @@ impl<'a> InferenceContext<'a> {
         let canonical_ty = self.canonicalize(ty.clone());
         let traits_in_scope = self.resolver.traits_in_scope(self.db.upcast());
 
-        method_resolution::iterate_method_candidates(
+        let mut not_visible = None;
+        let res = method_resolution::iterate_method_candidates(
             &canonical_ty.value,
             self.db,
             self.table.trait_env.clone(),
@@ -241,7 +244,7 @@ impl<'a> InferenceContext<'a> {
             VisibleFromModule::Filter(self.resolver.module()),
             Some(name),
             method_resolution::LookupMode::Path,
-            move |_ty, item| {
+            |_ty, item, visible| {
                 let (def, container) = match item {
                     AssocItemId::FunctionId(f) => {
                         (ValueNs::FunctionId(f), f.lookup(self.db.upcast()).container)
@@ -259,7 +262,7 @@ impl<'a> InferenceContext<'a> {
                         let impl_self_ty =
                             self.db.impl_self_ty(impl_id).substitute(Interner, &impl_substs);
                         self.unify(&impl_self_ty, &ty);
-                        Some(impl_substs)
+                        impl_substs
                     }
                     ItemContainerId::TraitId(trait_) => {
                         // we're picking this method
@@ -268,15 +271,32 @@ impl<'a> InferenceContext<'a> {
                             .fill_with_inference_vars(&mut self.table)
                             .build();
                         self.push_obligation(trait_ref.clone().cast(Interner));
-                        Some(trait_ref.substitution)
+                        trait_ref.substitution
+                    }
+                    ItemContainerId::ModuleId(_) | ItemContainerId::ExternBlockId(_) => {
+                        never!("assoc item contained in module/extern block");
+                        return None;
                     }
-                    ItemContainerId::ModuleId(_) | ItemContainerId::ExternBlockId(_) => None,
                 };
 
-                self.write_assoc_resolution(id, item);
-                Some((def, substs))
+                if visible {
+                    Some((def, item, Some(substs), true))
+                } else {
+                    if not_visible.is_none() {
+                        not_visible = Some((def, item, Some(substs), false));
+                    }
+                    None
+                }
             },
-        )
+        );
+        let res = res.or(not_visible);
+        if let Some((_, item, Some(ref substs), visible)) = res {
+            self.write_assoc_resolution(id, item, substs.clone());
+            if !visible {
+                self.push_diagnostic(InferenceDiagnostic::PrivateAssocItem { id, item })
+            }
+        }
+        res.map(|(def, _, substs, _)| (def, substs))
     }
 
     fn resolve_enum_variant_on_ty(

crates/hir-ty/src/infer/unify.rs

@@ -1,6 +1,6 @@
 //! Unification and canonicalization logic.
 
-use std::{fmt, mem, sync::Arc};
+use std::{fmt, iter, mem, sync::Arc};
 
 use chalk_ir::{
     cast::Cast, fold::TypeFoldable, interner::HasInterner, zip::Zip, CanonicalVarKind, FloatTy,
@@ -128,9 +128,13 @@ pub(crate) fn unify(
     ))
 }
 
-#[derive(Copy, Clone, Debug)]
-pub(crate) struct TypeVariableData {
-    diverging: bool,
+bitflags::bitflags! {
+    #[derive(Default)]
+    pub(crate) struct TypeVariableFlags: u8 {
+        const DIVERGING = 1 << 0;
+        const INTEGER = 1 << 1;
+        const FLOAT = 1 << 2;
+    }
 }
 
 type ChalkInferenceTable = chalk_solve::infer::InferenceTable<Interner>;
@@ -140,14 +144,14 @@ pub(crate) struct InferenceTable<'a> {
     pub(crate) db: &'a dyn HirDatabase,
     pub(crate) trait_env: Arc<TraitEnvironment>,
     var_unification_table: ChalkInferenceTable,
-    type_variable_table: Vec<TypeVariableData>,
+    type_variable_table: Vec<TypeVariableFlags>,
     pending_obligations: Vec<Canonicalized<InEnvironment<Goal>>>,
 }
 
 pub(crate) struct InferenceTableSnapshot {
     var_table_snapshot: chalk_solve::infer::InferenceSnapshot<Interner>,
     pending_obligations: Vec<Canonicalized<InEnvironment<Goal>>>,
-    type_variable_table_snapshot: Vec<TypeVariableData>,
+    type_variable_table_snapshot: Vec<TypeVariableFlags>,
 }
 
 impl<'a> InferenceTable<'a> {
@@ -169,19 +173,19 @@ impl<'a> InferenceTable<'a> {
     /// result.
     pub(super) fn propagate_diverging_flag(&mut self) {
         for i in 0..self.type_variable_table.len() {
-            if !self.type_variable_table[i].diverging {
+            if !self.type_variable_table[i].contains(TypeVariableFlags::DIVERGING) {
                 continue;
             }
             let v = InferenceVar::from(i as u32);
             let root = self.var_unification_table.inference_var_root(v);
             if let Some(data) = self.type_variable_table.get_mut(root.index() as usize) {
-                data.diverging = true;
+                *data |= TypeVariableFlags::DIVERGING;
             }
         }
     }
 
     pub(super) fn set_diverging(&mut self, iv: InferenceVar, diverging: bool) {
-        self.type_variable_table[iv.index() as usize].diverging = diverging;
+        self.type_variable_table[iv.index() as usize].set(TypeVariableFlags::DIVERGING, diverging);
     }
 
     fn fallback_value(&self, iv: InferenceVar, kind: TyVariableKind) -> Ty {
@@ -189,7 +193,7 @@ impl<'a> InferenceTable<'a> {
             _ if self
                 .type_variable_table
                 .get(iv.index() as usize)
-                .map_or(false, |data| data.diverging) =>
+                .map_or(false, |data| data.contains(TypeVariableFlags::DIVERGING)) =>
             {
                 TyKind::Never
             }
@@ -247,10 +251,8 @@ impl<'a> InferenceTable<'a> {
     }
 
     fn extend_type_variable_table(&mut self, to_index: usize) {
-        self.type_variable_table.extend(
-            (0..1 + to_index - self.type_variable_table.len())
-                .map(|_| TypeVariableData { diverging: false }),
-        );
+        let count = to_index - self.type_variable_table.len() + 1;
+        self.type_variable_table.extend(iter::repeat(TypeVariableFlags::default()).take(count));
     }
 
     fn new_var(&mut self, kind: TyVariableKind, diverging: bool) -> Ty {
@@ -258,7 +260,15 @@ impl<'a> InferenceTable<'a> {
         // Chalk might have created some type variables for its own purposes that we don't know about...
         self.extend_type_variable_table(var.index() as usize);
         assert_eq!(var.index() as usize, self.type_variable_table.len() - 1);
-        self.type_variable_table[var.index() as usize].diverging = diverging;
+        let flags = self.type_variable_table.get_mut(var.index() as usize).unwrap();
+        if diverging {
+            *flags |= TypeVariableFlags::DIVERGING;
+        }
+        if matches!(kind, TyVariableKind::Integer) {
+            *flags |= TypeVariableFlags::INTEGER;
+        } else if matches!(kind, TyVariableKind::Float) {
+            *flags |= TypeVariableFlags::FLOAT;
+        }
         var.to_ty_with_kind(Interner, kind)
     }
 
@@ -340,6 +350,51 @@ impl<'a> InferenceTable<'a> {
         self.resolve_with_fallback(t, &|_, _, d, _| d)
     }
 
+    /// Apply a fallback to unresolved scalar types. Integer type variables and float type
+    /// variables are replaced with i32 and f64, respectively.
+    ///
+    /// This method is only intended to be called just before returning inference results (i.e. in
+    /// `InferenceContext::resolve_all()`).
+    ///
+    /// FIXME: This method currently doesn't apply fallback to unconstrained general type variables
+    /// whereas rustc replaces them with `()` or `!`.
+    pub(super) fn fallback_if_possible(&mut self) {
+        let int_fallback = TyKind::Scalar(Scalar::Int(IntTy::I32)).intern(Interner);
+        let float_fallback = TyKind::Scalar(Scalar::Float(FloatTy::F64)).intern(Interner);
+
+        let scalar_vars: Vec<_> = self
+            .type_variable_table
+            .iter()
+            .enumerate()
+            .filter_map(|(index, flags)| {
+                let kind = if flags.contains(TypeVariableFlags::INTEGER) {
+                    TyVariableKind::Integer
+                } else if flags.contains(TypeVariableFlags::FLOAT) {
+                    TyVariableKind::Float
+                } else {
+                    return None;
+                };
+
+                // FIXME: This is not really the nicest way to get `InferenceVar`s. Can we get them
+                // without directly constructing them from `index`?
+                let var = InferenceVar::from(index as u32).to_ty(Interner, kind);
+                Some(var)
+            })
+            .collect();
+
+        for var in scalar_vars {
+            let maybe_resolved = self.resolve_ty_shallow(&var);
+            if let TyKind::InferenceVar(_, kind) = maybe_resolved.kind(Interner) {
+                let fallback = match kind {
+                    TyVariableKind::Integer => &int_fallback,
+                    TyVariableKind::Float => &float_fallback,
+                    TyVariableKind::General => unreachable!(),
+                };
+                self.unify(&var, fallback);
+            }
+        }
+    }
+
     /// Unify two relatable values (e.g. `Ty`) and register new trait goals that arise from that.
     pub(crate) fn unify<T: ?Sized + Zip<Interner>>(&mut self, ty1: &T, ty2: &T) -> bool {
         let result = match self.try_unify(ty1, ty2) {

crates/hir-ty/src/interner.rs

@@ -143,7 +143,7 @@ impl chalk_ir::interner::Interner for Interner {
 
     fn debug_goal(goal: &Goal<Interner>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         let goal_data = goal.data(Interner);
-        Some(write!(fmt, "{:?}", goal_data))
+        Some(write!(fmt, "{goal_data:?}"))
     }
 
     fn debug_goals(
@@ -228,7 +228,7 @@ impl chalk_ir::interner::Interner for Interner {
         Interned::new(InternedWrapper(chalk_ir::TyData { kind, flags }))
     }
 
-    fn ty_data<'a>(self, ty: &'a Self::InternedType) -> &'a chalk_ir::TyData<Self> {
+    fn ty_data(self, ty: &Self::InternedType) -> &chalk_ir::TyData<Self> {
         &ty.0
     }
 
@@ -236,10 +236,7 @@ impl chalk_ir::interner::Interner for Interner {
         Interned::new(InternedWrapper(lifetime))
     }
 
-    fn lifetime_data<'a>(
-        self,
-        lifetime: &'a Self::InternedLifetime,
-    ) -> &'a chalk_ir::LifetimeData<Self> {
+    fn lifetime_data(self, lifetime: &Self::InternedLifetime) -> &chalk_ir::LifetimeData<Self> {
         &lifetime.0
     }
 
@@ -247,7 +244,7 @@ impl chalk_ir::interner::Interner for Interner {
         Interned::new(InternedWrapper(constant))
     }
 
-    fn const_data<'a>(self, constant: &'a Self::InternedConst) -> &'a chalk_ir::ConstData<Self> {
+    fn const_data(self, constant: &Self::InternedConst) -> &chalk_ir::ConstData<Self> {
         &constant.0
     }
 
@@ -267,10 +264,10 @@ impl chalk_ir::interner::Interner for Interner {
         parameter
     }
 
-    fn generic_arg_data<'a>(
+    fn generic_arg_data(
         self,
-        parameter: &'a Self::InternedGenericArg,
-    ) -> &'a chalk_ir::GenericArgData<Self> {
+        parameter: &Self::InternedGenericArg,
+    ) -> &chalk_ir::GenericArgData<Self> {
         parameter
     }
 
@@ -285,11 +282,11 @@ impl chalk_ir::interner::Interner for Interner {
         data.into_iter().collect()
     }
 
-    fn goal_data<'a>(self, goal: &'a Self::InternedGoal) -> &'a GoalData<Self> {
+    fn goal_data(self, goal: &Self::InternedGoal) -> &GoalData<Self> {
         goal
     }
 
-    fn goals_data<'a>(self, goals: &'a Self::InternedGoals) -> &'a [Goal<Interner>] {
+    fn goals_data(self, goals: &Self::InternedGoals) -> &[Goal<Interner>] {
         goals
     }
 
@@ -300,10 +297,7 @@ impl chalk_ir::interner::Interner for Interner {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn substitution_data<'a>(
-        self,
-        substitution: &'a Self::InternedSubstitution,
-    ) -> &'a [GenericArg] {
+    fn substitution_data(self, substitution: &Self::InternedSubstitution) -> &[GenericArg] {
         &substitution.as_ref().0
     }
 
@@ -314,10 +308,10 @@ impl chalk_ir::interner::Interner for Interner {
         data
     }
 
-    fn program_clause_data<'a>(
+    fn program_clause_data(
         self,
-        clause: &'a Self::InternedProgramClause,
-    ) -> &'a chalk_ir::ProgramClauseData<Self> {
+        clause: &Self::InternedProgramClause,
+    ) -> &chalk_ir::ProgramClauseData<Self> {
         clause
     }
 
@@ -328,10 +322,10 @@ impl chalk_ir::interner::Interner for Interner {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn program_clauses_data<'a>(
+    fn program_clauses_data(
         self,
-        clauses: &'a Self::InternedProgramClauses,
-    ) -> &'a [chalk_ir::ProgramClause<Self>] {
+        clauses: &Self::InternedProgramClauses,
+    ) -> &[chalk_ir::ProgramClause<Self>] {
         clauses
     }
 
@@ -342,10 +336,10 @@ impl chalk_ir::interner::Interner for Interner {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn quantified_where_clauses_data<'a>(
+    fn quantified_where_clauses_data(
         self,
-        clauses: &'a Self::InternedQuantifiedWhereClauses,
-    ) -> &'a [chalk_ir::QuantifiedWhereClause<Self>] {
+        clauses: &Self::InternedQuantifiedWhereClauses,
+    ) -> &[chalk_ir::QuantifiedWhereClause<Self>] {
         clauses
     }
 
@@ -356,10 +350,10 @@ impl chalk_ir::interner::Interner for Interner {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn variable_kinds_data<'a>(
+    fn variable_kinds_data(
         self,
-        parameter_kinds: &'a Self::InternedVariableKinds,
-    ) -> &'a [chalk_ir::VariableKind<Self>] {
+        parameter_kinds: &Self::InternedVariableKinds,
+    ) -> &[chalk_ir::VariableKind<Self>] {
         &parameter_kinds.as_ref().0
     }
 
@@ -370,10 +364,10 @@ impl chalk_ir::interner::Interner for Interner {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn canonical_var_kinds_data<'a>(
+    fn canonical_var_kinds_data(
         self,
-        canonical_var_kinds: &'a Self::InternedCanonicalVarKinds,
-    ) -> &'a [chalk_ir::CanonicalVarKind<Self>] {
+        canonical_var_kinds: &Self::InternedCanonicalVarKinds,
+    ) -> &[chalk_ir::CanonicalVarKind<Self>] {
         canonical_var_kinds
     }
 
@@ -384,10 +378,10 @@ impl chalk_ir::interner::Interner for Interner {
         data.into_iter().collect()
     }
 
-    fn constraints_data<'a>(
+    fn constraints_data(
         self,
-        constraints: &'a Self::InternedConstraints,
-    ) -> &'a [chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>] {
+        constraints: &Self::InternedConstraints,
+    ) -> &[chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>] {
         constraints
     }
     fn debug_closure_id(
@@ -410,10 +404,7 @@ impl chalk_ir::interner::Interner for Interner {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn variances_data<'a>(
-        self,
-        variances: &'a Self::InternedVariances,
-    ) -> &'a [chalk_ir::Variance] {
+    fn variances_data(self, variances: &Self::InternedVariances) -> &[chalk_ir::Variance] {
         variances
     }
 }

crates/hir-ty/src/lang_items.rs

@@ -0,0 +1,20 @@
+//! Functions to detect special lang items
+
+use hir_def::{AdtId, HasModule};
+use hir_expand::name;
+
+use crate::db::HirDatabase;
+
+pub fn is_box(adt: AdtId, db: &dyn HirDatabase) -> bool {
+    let owned_box = name![owned_box].to_smol_str();
+    let krate = adt.module(db.upcast()).krate();
+    let box_adt = db.lang_item(krate, owned_box).and_then(|it| it.as_struct()).map(AdtId::from);
+    Some(adt) == box_adt
+}
+
+pub fn is_unsafe_cell(adt: AdtId, db: &dyn HirDatabase) -> bool {
+    let owned_box = name![unsafe_cell].to_smol_str();
+    let krate = adt.module(db.upcast()).krate();
+    let box_adt = db.lang_item(krate, owned_box).and_then(|it| it.as_struct()).map(AdtId::from);
+    Some(adt) == box_adt
+}

crates/hir-ty/src/layout.rs

@@ -0,0 +1,279 @@
+//! Compute the binary representation of a type
+
+use std::sync::Arc;
+
+use base_db::CrateId;
+use chalk_ir::{AdtId, TyKind};
+use hir_def::{
+    layout::{
+        Abi, FieldsShape, Integer, Layout, LayoutCalculator, LayoutError, Primitive, ReprOptions,
+        RustcEnumVariantIdx, Scalar, Size, StructKind, TargetDataLayout, Variants, WrappingRange,
+    },
+    LocalFieldId,
+};
+use stdx::never;
+
+use crate::{db::HirDatabase, Interner, Substitution, Ty};
+
+use self::adt::struct_variant_idx;
+pub use self::{
+    adt::{layout_of_adt_query, layout_of_adt_recover},
+    target::target_data_layout_query,
+};
+
+macro_rules! user_error {
+    ($x: expr) => {
+        return Err(LayoutError::UserError(format!($x)))
+    };
+}
+
+mod adt;
+mod target;
+
+struct LayoutCx<'a> {
+    db: &'a dyn HirDatabase,
+    krate: CrateId,
+}
+
+impl LayoutCalculator for LayoutCx<'_> {
+    type TargetDataLayoutRef = Arc<TargetDataLayout>;
+
+    fn delay_bug(&self, txt: &str) {
+        never!("{}", txt);
+    }
+
+    fn current_data_layout(&self) -> Arc<TargetDataLayout> {
+        self.db.target_data_layout(self.krate)
+    }
+}
+
+fn scalar_unit(dl: &TargetDataLayout, value: Primitive) -> Scalar {
+    Scalar::Initialized { value, valid_range: WrappingRange::full(value.size(dl)) }
+}
+
+fn scalar(dl: &TargetDataLayout, value: Primitive) -> Layout {
+    Layout::scalar(dl, scalar_unit(dl, value))
+}
+
+pub fn layout_of_ty(db: &dyn HirDatabase, ty: &Ty, krate: CrateId) -> Result<Layout, LayoutError> {
+    let cx = LayoutCx { db, krate };
+    let dl = &*cx.current_data_layout();
+    Ok(match ty.kind(Interner) {
+        TyKind::Adt(AdtId(def), subst) => db.layout_of_adt(*def, subst.clone())?,
+        TyKind::Scalar(s) => match s {
+            chalk_ir::Scalar::Bool => Layout::scalar(
+                dl,
+                Scalar::Initialized {
+                    value: Primitive::Int(Integer::I8, false),
+                    valid_range: WrappingRange { start: 0, end: 1 },
+                },
+            ),
+            chalk_ir::Scalar::Char => Layout::scalar(
+                dl,
+                Scalar::Initialized {
+                    value: Primitive::Int(Integer::I32, false),
+                    valid_range: WrappingRange { start: 0, end: 0x10FFFF },
+                },
+            ),
+            chalk_ir::Scalar::Int(i) => scalar(
+                dl,
+                Primitive::Int(
+                    match i {
+                        chalk_ir::IntTy::Isize => dl.ptr_sized_integer(),
+                        chalk_ir::IntTy::I8 => Integer::I8,
+                        chalk_ir::IntTy::I16 => Integer::I16,
+                        chalk_ir::IntTy::I32 => Integer::I32,
+                        chalk_ir::IntTy::I64 => Integer::I64,
+                        chalk_ir::IntTy::I128 => Integer::I128,
+                    },
+                    true,
+                ),
+            ),
+            chalk_ir::Scalar::Uint(i) => scalar(
+                dl,
+                Primitive::Int(
+                    match i {
+                        chalk_ir::UintTy::Usize => dl.ptr_sized_integer(),
+                        chalk_ir::UintTy::U8 => Integer::I8,
+                        chalk_ir::UintTy::U16 => Integer::I16,
+                        chalk_ir::UintTy::U32 => Integer::I32,
+                        chalk_ir::UintTy::U64 => Integer::I64,
+                        chalk_ir::UintTy::U128 => Integer::I128,
+                    },
+                    false,
+                ),
+            ),
+            chalk_ir::Scalar::Float(f) => scalar(
+                dl,
+                match f {
+                    chalk_ir::FloatTy::F32 => Primitive::F32,
+                    chalk_ir::FloatTy::F64 => Primitive::F64,
+                },
+            ),
+        },
+        TyKind::Tuple(len, tys) => {
+            let kind = if *len == 0 { StructKind::AlwaysSized } else { StructKind::MaybeUnsized };
+
+            let fields = tys
+                .iter(Interner)
+                .map(|k| layout_of_ty(db, k.assert_ty_ref(Interner), krate))
+                .collect::<Result<Vec<_>, _>>()?;
+            let fields = fields.iter().collect::<Vec<_>>();
+            let fields = fields.iter().collect::<Vec<_>>();
+            cx.univariant(dl, &fields, &ReprOptions::default(), kind).ok_or(LayoutError::Unknown)?
+        }
+        TyKind::Array(element, count) => {
+            let count = match count.data(Interner).value {
+                chalk_ir::ConstValue::Concrete(c) => match c.interned {
+                    hir_def::type_ref::ConstScalar::Int(x) => x as u64,
+                    hir_def::type_ref::ConstScalar::UInt(x) => x as u64,
+                    hir_def::type_ref::ConstScalar::Unknown => {
+                        user_error!("unknown const generic parameter")
+                    }
+                    _ => user_error!("mismatched type of const generic parameter"),
+                },
+                _ => return Err(LayoutError::HasPlaceholder),
+            };
+            let element = layout_of_ty(db, element, krate)?;
+            let size = element.size.checked_mul(count, dl).ok_or(LayoutError::SizeOverflow)?;
+
+            let abi = if count != 0 && matches!(element.abi, Abi::Uninhabited) {
+                Abi::Uninhabited
+            } else {
+                Abi::Aggregate { sized: true }
+            };
+
+            let largest_niche = if count != 0 { element.largest_niche } else { None };
+
+            Layout {
+                variants: Variants::Single { index: struct_variant_idx() },
+                fields: FieldsShape::Array { stride: element.size, count },
+                abi,
+                largest_niche,
+                align: element.align,
+                size,
+            }
+        }
+        TyKind::Slice(element) => {
+            let element = layout_of_ty(db, element, krate)?;
+            Layout {
+                variants: Variants::Single { index: struct_variant_idx() },
+                fields: FieldsShape::Array { stride: element.size, count: 0 },
+                abi: Abi::Aggregate { sized: false },
+                largest_niche: None,
+                align: element.align,
+                size: Size::ZERO,
+            }
+        }
+        // Potentially-wide pointers.
+        TyKind::Ref(_, _, pointee) | TyKind::Raw(_, pointee) => {
+            let mut data_ptr = scalar_unit(dl, Primitive::Pointer);
+            if matches!(ty.kind(Interner), TyKind::Ref(..)) {
+                data_ptr.valid_range_mut().start = 1;
+            }
+
+            // let pointee = tcx.normalize_erasing_regions(param_env, pointee);
+            // if pointee.is_sized(tcx.at(DUMMY_SP), param_env) {
+            //     return Ok(tcx.intern_layout(LayoutS::scalar(cx, data_ptr)));
+            // }
+
+            let unsized_part = struct_tail_erasing_lifetimes(db, pointee.clone());
+            let metadata = match unsized_part.kind(Interner) {
+                TyKind::Slice(_) | TyKind::Str => {
+                    scalar_unit(dl, Primitive::Int(dl.ptr_sized_integer(), false))
+                }
+                TyKind::Dyn(..) => {
+                    let mut vtable = scalar_unit(dl, Primitive::Pointer);
+                    vtable.valid_range_mut().start = 1;
+                    vtable
+                }
+                _ => {
+                    // pointee is sized
+                    return Ok(Layout::scalar(dl, data_ptr));
+                }
+            };
+
+            // Effectively a (ptr, meta) tuple.
+            cx.scalar_pair(data_ptr, metadata)
+        }
+        TyKind::FnDef(_, _) => layout_of_unit(&cx, dl)?,
+        TyKind::Str => Layout {
+            variants: Variants::Single { index: struct_variant_idx() },
+            fields: FieldsShape::Array { stride: Size::from_bytes(1), count: 0 },
+            abi: Abi::Aggregate { sized: false },
+            largest_niche: None,
+            align: dl.i8_align,
+            size: Size::ZERO,
+        },
+        TyKind::Never => Layout {
+            variants: Variants::Single { index: struct_variant_idx() },
+            fields: FieldsShape::Primitive,
+            abi: Abi::Uninhabited,
+            largest_niche: None,
+            align: dl.i8_align,
+            size: Size::ZERO,
+        },
+        TyKind::Dyn(_) | TyKind::Foreign(_) => {
+            let mut unit = layout_of_unit(&cx, dl)?;
+            match unit.abi {
+                Abi::Aggregate { ref mut sized } => *sized = false,
+                _ => user_error!("bug"),
+            }
+            unit
+        }
+        TyKind::Function(_) => {
+            let mut ptr = scalar_unit(dl, Primitive::Pointer);
+            ptr.valid_range_mut().start = 1;
+            Layout::scalar(dl, ptr)
+        }
+        TyKind::Closure(_, _)
+        | TyKind::OpaqueType(_, _)
+        | TyKind::Generator(_, _)
+        | TyKind::GeneratorWitness(_, _) => return Err(LayoutError::NotImplemented),
+        TyKind::AssociatedType(_, _)
+        | TyKind::Error
+        | TyKind::Alias(_)
+        | TyKind::Placeholder(_)
+        | TyKind::BoundVar(_)
+        | TyKind::InferenceVar(_, _) => return Err(LayoutError::HasPlaceholder),
+    })
+}
+
+fn layout_of_unit(cx: &LayoutCx<'_>, dl: &TargetDataLayout) -> Result<Layout, LayoutError> {
+    cx.univariant::<RustcEnumVariantIdx, &&Layout>(
+        dl,
+        &[],
+        &ReprOptions::default(),
+        StructKind::AlwaysSized,
+    )
+    .ok_or(LayoutError::Unknown)
+}
+
+fn struct_tail_erasing_lifetimes(db: &dyn HirDatabase, pointee: Ty) -> Ty {
+    match pointee.kind(Interner) {
+        TyKind::Adt(AdtId(adt), subst) => match adt {
+            &hir_def::AdtId::StructId(i) => {
+                let data = db.struct_data(i);
+                let mut it = data.variant_data.fields().iter().rev();
+                match it.next() {
+                    Some((f, _)) => field_ty(db, i.into(), f, subst),
+                    None => pointee,
+                }
+            }
+            _ => pointee,
+        },
+        _ => pointee,
+    }
+}
+
+fn field_ty(
+    db: &dyn HirDatabase,
+    def: hir_def::VariantId,
+    fd: LocalFieldId,
+    subst: &Substitution,
+) -> Ty {
+    db.field_types(def)[fd].clone().substitute(Interner, subst)
+}
+
+#[cfg(test)]
+mod tests;

crates/hir-ty/src/layout/adt.rs

@@ -0,0 +1,134 @@
+//! Compute the binary representation of structs, unions and enums
+
+use std::ops::Bound;
+
+use hir_def::{
+    adt::VariantData,
+    layout::{Integer, IntegerExt, Layout, LayoutCalculator, LayoutError, RustcEnumVariantIdx},
+    AdtId, EnumVariantId, HasModule, LocalEnumVariantId, VariantId,
+};
+use la_arena::RawIdx;
+use smallvec::SmallVec;
+
+use crate::{db::HirDatabase, lang_items::is_unsafe_cell, layout::field_ty, Substitution};
+
+use super::{layout_of_ty, LayoutCx};
+
+pub(crate) fn struct_variant_idx() -> RustcEnumVariantIdx {
+    RustcEnumVariantIdx(LocalEnumVariantId::from_raw(RawIdx::from(0)))
+}
+
+pub fn layout_of_adt_query(
+    db: &dyn HirDatabase,
+    def: AdtId,
+    subst: Substitution,
+) -> Result<Layout, LayoutError> {
+    let cx = LayoutCx { db, krate: def.module(db.upcast()).krate() };
+    let dl = cx.current_data_layout();
+    let handle_variant = |def: VariantId, var: &VariantData| {
+        var.fields()
+            .iter()
+            .map(|(fd, _)| layout_of_ty(db, &field_ty(db, def, fd, &subst), cx.krate))
+            .collect::<Result<Vec<_>, _>>()
+    };
+    let (variants, is_enum, is_union, repr) = match def {
+        AdtId::StructId(s) => {
+            let data = db.struct_data(s);
+            let mut r = SmallVec::<[_; 1]>::new();
+            r.push(handle_variant(s.into(), &data.variant_data)?);
+            (r, false, false, data.repr.unwrap_or_default())
+        }
+        AdtId::UnionId(id) => {
+            let data = db.union_data(id);
+            let mut r = SmallVec::new();
+            r.push(handle_variant(id.into(), &data.variant_data)?);
+            (r, false, true, data.repr.unwrap_or_default())
+        }
+        AdtId::EnumId(e) => {
+            let data = db.enum_data(e);
+            let r = data
+                .variants
+                .iter()
+                .map(|(idx, v)| {
+                    handle_variant(
+                        EnumVariantId { parent: e, local_id: idx }.into(),
+                        &v.variant_data,
+                    )
+                })
+                .collect::<Result<SmallVec<_>, _>>()?;
+            (r, true, false, data.repr.unwrap_or_default())
+        }
+    };
+    let variants =
+        variants.iter().map(|x| x.iter().collect::<Vec<_>>()).collect::<SmallVec<[_; 1]>>();
+    let variants = variants.iter().map(|x| x.iter().collect()).collect();
+    if is_union {
+        cx.layout_of_union(&repr, &variants).ok_or(LayoutError::Unknown)
+    } else {
+        cx.layout_of_struct_or_enum(
+            &repr,
+            &variants,
+            is_enum,
+            is_unsafe_cell(def, db),
+            layout_scalar_valid_range(db, def),
+            |min, max| Integer::repr_discr(&dl, &repr, min, max).unwrap_or((Integer::I8, false)),
+            variants.iter_enumerated().filter_map(|(id, _)| {
+                let AdtId::EnumId(e) = def else { return None };
+                let d = match db
+                    .const_eval_variant(EnumVariantId { parent: e, local_id: id.0 })
+                    .ok()?
+                {
+                    crate::consteval::ComputedExpr::Literal(l) => match l {
+                        hir_def::expr::Literal::Int(i, _) => i,
+                        hir_def::expr::Literal::Uint(i, _) => i as i128,
+                        _ => return None,
+                    },
+                    _ => return None,
+                };
+                Some((id, d))
+            }),
+            // FIXME: The current code for niche-filling relies on variant indices
+            // instead of actual discriminants, so enums with
+            // explicit discriminants (RFC #2363) would misbehave and we should disable
+            // niche optimization for them.
+            // The code that do it in rustc:
+            // repr.inhibit_enum_layout_opt() || def
+            //     .variants()
+            //     .iter_enumerated()
+            //     .any(|(i, v)| v.discr != ty::VariantDiscr::Relative(i.as_u32()))
+            repr.inhibit_enum_layout_opt(),
+            !is_enum
+                && variants
+                    .iter()
+                    .next()
+                    .and_then(|x| x.last().map(|x| x.is_unsized()))
+                    .unwrap_or(true),
+        )
+        .ok_or(LayoutError::SizeOverflow)
+    }
+}
+
+fn layout_scalar_valid_range(db: &dyn HirDatabase, def: AdtId) -> (Bound<u128>, Bound<u128>) {
+    let attrs = db.attrs(def.into());
+    let get = |name| {
+        let attr = attrs.by_key(name).tt_values();
+        for tree in attr {
+            if let Some(x) = tree.token_trees.first() {
+                if let Ok(x) = x.to_string().parse() {
+                    return Bound::Included(x);
+                }
+            }
+        }
+        Bound::Unbounded
+    };
+    (get("rustc_layout_scalar_valid_range_start"), get("rustc_layout_scalar_valid_range_end"))
+}
+
+pub fn layout_of_adt_recover(
+    _: &dyn HirDatabase,
+    _: &[String],
+    _: &AdtId,
+    _: &Substitution,
+) -> Result<Layout, LayoutError> {
+    user_error!("infinite sized recursive type");
+}

crates/hir-ty/src/layout/target.rs

@@ -0,0 +1,36 @@
+//! Target dependent parameters needed for layouts
+
+use std::sync::Arc;
+
+use base_db::CrateId;
+use hir_def::layout::{Endian, Size, TargetDataLayout};
+
+use crate::db::HirDatabase;
+
+pub fn target_data_layout_query(db: &dyn HirDatabase, krate: CrateId) -> Arc<TargetDataLayout> {
+    let crate_graph = db.crate_graph();
+    let target_layout = &crate_graph[krate].target_layout;
+    let cfg_options = &crate_graph[krate].cfg_options;
+    Arc::new(
+        target_layout
+            .as_ref()
+            .and_then(|it| TargetDataLayout::parse_from_llvm_datalayout_string(it).ok())
+            .unwrap_or_else(|| {
+                let endian = match cfg_options.get_cfg_values("target_endian").next() {
+                    Some(x) if x.as_str() == "big" => Endian::Big,
+                    _ => Endian::Little,
+                };
+                let pointer_size = Size::from_bytes(
+                    match cfg_options.get_cfg_values("target_pointer_width").next() {
+                        Some(x) => match x.as_str() {
+                            "16" => 2,
+                            "32" => 4,
+                            _ => 8,
+                        },
+                        _ => 8,
+                    },
+                );
+                TargetDataLayout { endian, pointer_size, ..TargetDataLayout::default() }
+            }),
+    )
+}

crates/hir-ty/src/layout/tests.rs

@@ -0,0 +1,208 @@
+use base_db::fixture::WithFixture;
+use chalk_ir::{AdtId, TyKind};
+use hir_def::{
+    db::DefDatabase,
+    layout::{Layout, LayoutError},
+};
+
+use crate::{test_db::TestDB, Interner, Substitution};
+
+use super::layout_of_ty;
+
+fn eval_goal(ra_fixture: &str, minicore: &str) -> Result<Layout, LayoutError> {
+    // using unstable cargo features failed, fall back to using plain rustc
+    let mut cmd = std::process::Command::new("rustc");
+    cmd.args(["-Z", "unstable-options", "--print", "target-spec-json"]).env("RUSTC_BOOTSTRAP", "1");
+    let output = cmd.output().unwrap();
+    assert!(output.status.success(), "{}", output.status);
+    let stdout = String::from_utf8(output.stdout).unwrap();
+    let target_data_layout =
+        stdout.split_once(r#""data-layout": ""#).unwrap().1.split_once('"').unwrap().0.to_owned();
+
+    let ra_fixture = format!(
+        "{minicore}//- /main.rs crate:test target_data_layout:{target_data_layout}\n{ra_fixture}",
+    );
+
+    let (db, file_id) = TestDB::with_single_file(&ra_fixture);
+    let module_id = db.module_for_file(file_id);
+    let def_map = module_id.def_map(&db);
+    let scope = &def_map[module_id.local_id].scope;
+    let adt_id = scope
+        .declarations()
+        .find_map(|x| match x {
+            hir_def::ModuleDefId::AdtId(x) => {
+                let name = match x {
+                    hir_def::AdtId::StructId(x) => db.struct_data(x).name.to_smol_str(),
+                    hir_def::AdtId::UnionId(x) => db.union_data(x).name.to_smol_str(),
+                    hir_def::AdtId::EnumId(x) => db.enum_data(x).name.to_smol_str(),
+                };
+                (name == "Goal").then_some(x)
+            }
+            _ => None,
+        })
+        .unwrap();
+    let goal_ty = TyKind::Adt(AdtId(adt_id), Substitution::empty(Interner)).intern(Interner);
+    layout_of_ty(&db, &goal_ty, module_id.krate())
+}
+
+#[track_caller]
+fn check_size_and_align(ra_fixture: &str, minicore: &str, size: u64, align: u64) {
+    let l = eval_goal(ra_fixture, minicore).unwrap();
+    assert_eq!(l.size.bytes(), size);
+    assert_eq!(l.align.abi.bytes(), align);
+}
+
+#[track_caller]
+fn check_fail(ra_fixture: &str, e: LayoutError) {
+    let r = eval_goal(ra_fixture, "");
+    assert_eq!(r, Err(e));
+}
+
+macro_rules! size_and_align {
+    (minicore: $($x:tt),*;$($t:tt)*) => {
+        {
+            #[allow(dead_code)]
+            $($t)*
+            check_size_and_align(
+                stringify!($($t)*),
+                &format!("//- minicore: {}\n", stringify!($($x),*)),
+                ::std::mem::size_of::<Goal>() as u64,
+                ::std::mem::align_of::<Goal>() as u64,
+            );
+        }
+    };
+    ($($t:tt)*) => {
+        {
+            #[allow(dead_code)]
+            $($t)*
+            check_size_and_align(
+                stringify!($($t)*),
+                "",
+                ::std::mem::size_of::<Goal>() as u64,
+                ::std::mem::align_of::<Goal>() as u64,
+            );
+        }
+    };
+}
+
+#[test]
+fn hello_world() {
+    size_and_align! {
+        struct Goal(i32);
+    }
+}
+
+#[test]
+fn field_order_optimization() {
+    size_and_align! {
+        struct Goal(u8, i32, u8);
+    }
+    size_and_align! {
+        #[repr(C)]
+        struct Goal(u8, i32, u8);
+    }
+}
+
+#[test]
+fn recursive() {
+    size_and_align! {
+        struct Goal {
+            left: &'static Goal,
+            right: &'static Goal,
+        }
+    }
+    size_and_align! {
+        struct BoxLike<T: ?Sized>(*mut T);
+        struct Goal(BoxLike<Goal>);
+    }
+    check_fail(
+        r#"struct Goal(Goal);"#,
+        LayoutError::UserError("infinite sized recursive type".to_string()),
+    );
+    check_fail(
+        r#"
+        struct Foo<T>(Foo<T>);
+        struct Goal(Foo<i32>);
+        "#,
+        LayoutError::UserError("infinite sized recursive type".to_string()),
+    );
+}
+
+#[test]
+fn generic() {
+    size_and_align! {
+        struct Pair<A, B>(A, B);
+        struct Goal(Pair<Pair<i32, u8>, i64>);
+    }
+    size_and_align! {
+        struct X<const N: usize> {
+            field1: [i32; N],
+            field2: [u8; N],
+        }
+        struct Goal(X<1000>);
+    }
+}
+
+#[test]
+fn enums() {
+    size_and_align! {
+        enum Goal {
+            Quit,
+            Move { x: i32, y: i32 },
+            ChangeColor(i32, i32, i32),
+        }
+    }
+}
+
+#[test]
+fn primitives() {
+    size_and_align! {
+        struct Goal(i32, i128, isize, usize, f32, f64, bool, char);
+    }
+}
+
+#[test]
+fn tuple() {
+    size_and_align! {
+        struct Goal((), (i32, u64, bool));
+    }
+}
+
+#[test]
+fn non_zero() {
+    size_and_align! {
+        minicore: non_zero, option;
+        use core::num::NonZeroU8;
+        struct Goal(Option<NonZeroU8>);
+    }
+}
+
+#[test]
+fn niche_optimization() {
+    size_and_align! {
+        minicore: option;
+        struct Goal(Option<&'static i32>);
+    }
+    size_and_align! {
+        minicore: option;
+        struct Goal(Option<Option<bool>>);
+    }
+}
+
+#[test]
+fn enums_with_discriminants() {
+    size_and_align! {
+        enum Goal {
+            A = 1000,
+            B = 2000,
+            C = 3000,
+        }
+    }
+    size_and_align! {
+        enum Goal {
+            A = 254,
+            B,
+            C, // implicitly becomes 256, so we need two bytes
+        }
+    }
+}

crates/hir-ty/src/lib.rs

@@ -27,6 +27,8 @@ pub mod display;
 pub mod method_resolution;
 pub mod primitive;
 pub mod traits;
+pub mod layout;
+pub mod lang_items;
 
 #[cfg(test)]
 mod tests;
@@ -38,7 +40,7 @@ use std::sync::Arc;
 use chalk_ir::{
     fold::{Shift, TypeFoldable},
     interner::HasInterner,
-    NoSolution, UniverseIndex,
+    NoSolution,
 };
 use hir_def::{expr::ExprId, type_ref::Rawness, TypeOrConstParamId};
 use hir_expand::name;
@@ -46,7 +48,9 @@ use itertools::Either;
 use traits::FnTrait;
 use utils::Generics;
 
-use crate::{consteval::unknown_const, db::HirDatabase, utils::generics};
+use crate::{
+    consteval::unknown_const, db::HirDatabase, infer::unify::InferenceTable, utils::generics,
+};
 
 pub use autoderef::autoderef;
 pub use builder::{ParamKind, TyBuilder};
@@ -511,7 +515,7 @@ where
     let mut error_replacer = ErrorReplacer { vars: 0 };
     let value = match t.clone().try_fold_with(&mut error_replacer, DebruijnIndex::INNERMOST) {
         Ok(t) => t,
-        Err(_) => panic!("Encountered unbound or inference vars in {:?}", t),
+        Err(_) => panic!("Encountered unbound or inference vars in {t:?}"),
     };
     let kinds = (0..error_replacer.vars).map(|_| {
         chalk_ir::CanonicalVarKind::new(
@@ -531,54 +535,31 @@ pub fn callable_sig_from_fnonce(
     let fn_once_trait = FnTrait::FnOnce.get_id(db, krate)?;
     let output_assoc_type = db.trait_data(fn_once_trait).associated_type_by_name(&name![Output])?;
 
+    let mut table = InferenceTable::new(db, env.clone());
     let b = TyBuilder::trait_ref(db, fn_once_trait);
     if b.remaining() != 2 {
         return None;
     }
-    let fn_once = b.push(self_ty.clone()).fill_with_bound_vars(DebruijnIndex::INNERMOST, 0).build();
-    let kinds = fn_once
-        .substitution
-        .iter(Interner)
-        .skip(1)
-        .map(|x| {
-            let vk = match x.data(Interner) {
-                chalk_ir::GenericArgData::Ty(_) => {
-                    chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)
-                }
-                chalk_ir::GenericArgData::Lifetime(_) => chalk_ir::VariableKind::Lifetime,
-                chalk_ir::GenericArgData::Const(c) => {
-                    chalk_ir::VariableKind::Const(c.data(Interner).ty.clone())
-                }
-            };
-            chalk_ir::WithKind::new(vk, UniverseIndex::ROOT)
-        })
-        .collect::<Vec<_>>();
 
-    // FIXME: chalk refuses to solve `<Self as FnOnce<^0.0>>::Output == ^0.1`, so we first solve
-    // `<Self as FnOnce<^0.0>>` and then replace `^0.0` with the concrete argument tuple.
-    let trait_env = env.env.clone();
-    let obligation = InEnvironment { goal: fn_once.cast(Interner), environment: trait_env };
-    let canonical =
-        Canonical { binders: CanonicalVarKinds::from_iter(Interner, kinds), value: obligation };
-    let subst = match db.trait_solve(krate, canonical) {
-        Some(Solution::Unique(vars)) => vars.value.subst,
-        _ => return None,
-    };
-    let args = subst.at(Interner, 0).ty(Interner)?;
-    let params = match args.kind(Interner) {
-        chalk_ir::TyKind::Tuple(_, subst) => {
-            subst.iter(Interner).filter_map(|arg| arg.ty(Interner).cloned()).collect::<Vec<_>>()
-        }
-        _ => return None,
-    };
+    // Register two obligations:
+    // - Self: FnOnce<?args_ty>
+    // - <Self as FnOnce<?args_ty>>::Output == ?ret_ty
+    let args_ty = table.new_type_var();
+    let trait_ref = b.push(self_ty.clone()).push(args_ty.clone()).build();
+    let projection = TyBuilder::assoc_type_projection(
+        db,
+        output_assoc_type,
+        Some(trait_ref.substitution.clone()),
+    )
+    .build();
+    table.register_obligation(trait_ref.cast(Interner));
+    let ret_ty = table.normalize_projection_ty(projection);
 
-    let fn_once =
-        TyBuilder::trait_ref(db, fn_once_trait).push(self_ty.clone()).push(args.clone()).build();
-    let projection =
-        TyBuilder::assoc_type_projection(db, output_assoc_type, Some(fn_once.substitution.clone()))
-            .build();
+    let ret_ty = table.resolve_completely(ret_ty);
+    let args_ty = table.resolve_completely(args_ty);
 
-    let ret_ty = db.normalize_projection(projection, env);
+    let params =
+        args_ty.as_tuple()?.iter(Interner).map(|it| it.assert_ty_ref(Interner)).cloned().collect();
 
-    Some(CallableSig::from_params_and_return(params, ret_ty.clone(), false, Safety::Safe))
+    Some(CallableSig::from_params_and_return(params, ret_ty, false, Safety::Safe))
 }

crates/hir-ty/src/lower.rs

@@ -603,9 +603,8 @@ impl<'a> TyLoweringContext<'a> {
     }
 
     fn select_associated_type(&self, res: Option<TypeNs>, segment: PathSegment<'_>) -> Ty {
-        let (def, res) = match (self.resolver.generic_def(), res) {
-            (Some(def), Some(res)) => (def, res),
-            _ => return TyKind::Error.intern(Interner),
+        let Some((def, res)) = self.resolver.generic_def().zip(res) else {
+            return TyKind::Error.intern(Interner);
         };
         let ty = named_associated_type_shorthand_candidates(
             self.db,
@@ -617,6 +616,21 @@ impl<'a> TyLoweringContext<'a> {
                     return None;
                 }
 
+                let parent_subst = t.substitution.clone();
+                let parent_subst = match self.type_param_mode {
+                    ParamLoweringMode::Placeholder => {
+                        // if we're lowering to placeholders, we have to put them in now.
+                        let generics = generics(self.db.upcast(), def);
+                        let s = generics.placeholder_subst(self.db);
+                        s.apply(parent_subst, Interner)
+                    }
+                    ParamLoweringMode::Variable => {
+                        // We need to shift in the bound vars, since
+                        // `named_associated_type_shorthand_candidates` does not do that.
+                        parent_subst.shifted_in_from(Interner, self.in_binders)
+                    }
+                };
+
                 // FIXME: `substs_from_path_segment()` pushes `TyKind::Error` for every parent
                 // generic params. It's inefficient to splice the `Substitution`s, so we may want
                 // that method to optionally take parent `Substitution` as we already know them at
@@ -632,22 +646,9 @@ impl<'a> TyLoweringContext<'a> {
 
                 let substs = Substitution::from_iter(
                     Interner,
-                    substs.iter(Interner).take(len_self).chain(t.substitution.iter(Interner)),
+                    substs.iter(Interner).take(len_self).chain(parent_subst.iter(Interner)),
                 );
 
-                let substs = match self.type_param_mode {
-                    ParamLoweringMode::Placeholder => {
-                        // if we're lowering to placeholders, we have to put
-                        // them in now
-                        let generics = generics(self.db.upcast(), def);
-                        let s = generics.placeholder_subst(self.db);
-                        s.apply(substs, Interner)
-                    }
-                    ParamLoweringMode::Variable => substs,
-                };
-                // We need to shift in the bound vars, since
-                // associated_type_shorthand_candidates does not do that
-                let substs = substs.shifted_in_from(Interner, self.in_binders);
                 Some(
                     TyKind::Alias(AliasTy::Projection(ProjectionTy {
                         associated_ty_id: to_assoc_type_id(associated_ty),
@@ -779,7 +780,7 @@ impl<'a> TyLoweringContext<'a> {
                         |_, c, ty| {
                             const_or_path_to_chalk(
                                 self.db,
-                                &self.resolver,
+                                self.resolver,
                                 ty,
                                 c,
                                 self.type_param_mode,
@@ -1190,9 +1191,9 @@ pub fn associated_type_shorthand_candidates<R>(
     db: &dyn HirDatabase,
     def: GenericDefId,
     res: TypeNs,
-    cb: impl FnMut(&Name, &TraitRef, TypeAliasId) -> Option<R>,
+    mut cb: impl FnMut(&Name, TypeAliasId) -> Option<R>,
 ) -> Option<R> {
-    named_associated_type_shorthand_candidates(db, def, res, None, cb)
+    named_associated_type_shorthand_candidates(db, def, res, None, |name, _, id| cb(name, id))
 }
 
 fn named_associated_type_shorthand_candidates<R>(
@@ -1202,6 +1203,9 @@ fn named_associated_type_shorthand_candidates<R>(
     def: GenericDefId,
     res: TypeNs,
     assoc_name: Option<Name>,
+    // Do NOT let `cb` touch `TraitRef` outside of `TyLoweringContext`. Its substitution contains
+    // free `BoundVar`s that need to be shifted and only `TyLoweringContext` knows how to do that
+    // properly (see `TyLoweringContext::select_associated_type()`).
     mut cb: impl FnMut(&Name, &TraitRef, TypeAliasId) -> Option<R>,
 ) -> Option<R> {
     let mut search = |t| {
@@ -1792,8 +1796,7 @@ pub(crate) fn impl_self_ty_query(db: &dyn HirDatabase, impl_id: ImplId) -> Binde
     let impl_data = db.impl_data(impl_id);
     let resolver = impl_id.resolver(db.upcast());
     let _cx = stdx::panic_context::enter(format!(
-        "impl_self_ty_query({:?} -> {:?} -> {:?})",
-        impl_id, impl_loc, impl_data
+        "impl_self_ty_query({impl_id:?} -> {impl_loc:?} -> {impl_data:?})"
     ));
     let generics = generics(db.upcast(), impl_id.into());
     let ctx =
@@ -1830,8 +1833,7 @@ pub(crate) fn impl_trait_query(db: &dyn HirDatabase, impl_id: ImplId) -> Option<
     let impl_data = db.impl_data(impl_id);
     let resolver = impl_id.resolver(db.upcast());
     let _cx = stdx::panic_context::enter(format!(
-        "impl_trait_query({:?} -> {:?} -> {:?})",
-        impl_id, impl_loc, impl_data
+        "impl_trait_query({impl_id:?} -> {impl_loc:?} -> {impl_data:?})"
     ));
     let ctx =
         TyLoweringContext::new(db, &resolver).with_type_param_mode(ParamLoweringMode::Variable);
@@ -1850,7 +1852,7 @@ pub(crate) fn return_type_impl_traits(
     let ctx_ret = TyLoweringContext::new(db, &resolver)
         .with_impl_trait_mode(ImplTraitLoweringMode::Opaque)
         .with_type_param_mode(ParamLoweringMode::Variable);
-    let _ret = (&ctx_ret).lower_ty(&data.ret_type);
+    let _ret = ctx_ret.lower_ty(&data.ret_type);
     let generics = generics(db.upcast(), def.into());
     let return_type_impl_traits =
         ReturnTypeImplTraits { impl_traits: ctx_ret.opaque_type_data.into_inner() };
@@ -1979,7 +1981,7 @@ fn fallback_bound_vars<T: TypeFoldable<Interner> + HasInterner<Interner = Intern
             if bound.index_if_innermost().map_or(true, is_allowed) {
                 bound.shifted_in_from(binders).to_const(Interner, ty)
             } else {
-                unknown_const(ty.clone())
+                unknown_const(ty)
             }
         },
     )

crates/hir-ty/src/method_resolution.rs

@@ -2,18 +2,17 @@
 //! For details about how this works in rustc, see the method lookup page in the
 //! [rustc guide](https://rust-lang.github.io/rustc-guide/method-lookup.html)
 //! and the corresponding code mostly in rustc_hir_analysis/check/method/probe.rs.
-use std::{iter, ops::ControlFlow, sync::Arc};
+use std::{ops::ControlFlow, sync::Arc};
 
-use arrayvec::ArrayVec;
 use base_db::{CrateId, Edition};
 use chalk_ir::{cast::Cast, Mutability, UniverseIndex};
 use hir_def::{
     data::ImplData, item_scope::ItemScope, nameres::DefMap, AssocItemId, BlockId, ConstId,
-    FunctionId, GenericDefId, HasModule, ImplId, ItemContainerId, Lookup, ModuleDefId, ModuleId,
-    TraitId,
+    FunctionId, HasModule, ImplId, ItemContainerId, Lookup, ModuleDefId, ModuleId, TraitId,
 };
 use hir_expand::name::Name;
 use rustc_hash::{FxHashMap, FxHashSet};
+use smallvec::{smallvec, SmallVec};
 use stdx::never;
 
 use crate::{
@@ -336,21 +335,18 @@ impl InherentImpls {
     }
 }
 
-pub(crate) fn inherent_impl_crates_query(
+pub(crate) fn incoherent_inherent_impl_crates(
     db: &dyn HirDatabase,
     krate: CrateId,
     fp: TyFingerprint,
-) -> ArrayVec<CrateId, 2> {
+) -> SmallVec<[CrateId; 2]> {
     let _p = profile::span("inherent_impl_crates_query");
-    let mut res = ArrayVec::new();
+    let mut res = SmallVec::new();
     let crate_graph = db.crate_graph();
 
+    // should pass crate for finger print and do reverse deps
+
     for krate in crate_graph.transitive_deps(krate) {
-        if res.is_full() {
-            // we don't currently look for or store more than two crates here,
-            // so don't needlessly look at more crates than necessary.
-            break;
-        }
         let impls = db.inherent_impls_in_crate(krate);
         if impls.map.get(&fp).map_or(false, |v| !v.is_empty()) {
             res.push(krate);
@@ -392,19 +388,40 @@ pub fn def_crates(
     db: &dyn HirDatabase,
     ty: &Ty,
     cur_crate: CrateId,
-) -> Option<ArrayVec<CrateId, 2>> {
-    let mod_to_crate_ids = |module: ModuleId| Some(iter::once(module.krate()).collect());
-
-    let fp = TyFingerprint::for_inherent_impl(ty);
-
+) -> Option<SmallVec<[CrateId; 2]>> {
     match ty.kind(Interner) {
-        TyKind::Adt(AdtId(def_id), _) => mod_to_crate_ids(def_id.module(db.upcast())),
-        TyKind::Foreign(id) => {
-            mod_to_crate_ids(from_foreign_def_id(*id).lookup(db.upcast()).module(db.upcast()))
+        &TyKind::Adt(AdtId(def_id), _) => {
+            let rustc_has_incoherent_inherent_impls = match def_id {
+                hir_def::AdtId::StructId(id) => {
+                    db.struct_data(id).rustc_has_incoherent_inherent_impls
+                }
+                hir_def::AdtId::UnionId(id) => {
+                    db.union_data(id).rustc_has_incoherent_inherent_impls
+                }
+                hir_def::AdtId::EnumId(id) => db.enum_data(id).rustc_has_incoherent_inherent_impls,
+            };
+            Some(if rustc_has_incoherent_inherent_impls {
+                db.incoherent_inherent_impl_crates(cur_crate, TyFingerprint::Adt(def_id))
+            } else {
+                smallvec![def_id.module(db.upcast()).krate()]
+            })
+        }
+        &TyKind::Foreign(id) => {
+            let alias = from_foreign_def_id(id);
+            Some(if db.type_alias_data(alias).rustc_has_incoherent_inherent_impls {
+                db.incoherent_inherent_impl_crates(cur_crate, TyFingerprint::ForeignType(id))
+            } else {
+                smallvec![alias.module(db.upcast()).krate()]
+            })
+        }
+        TyKind::Dyn(_) => {
+            let trait_id = ty.dyn_trait()?;
+            Some(if db.trait_data(trait_id).rustc_has_incoherent_inherent_impls {
+                db.incoherent_inherent_impl_crates(cur_crate, TyFingerprint::Dyn(trait_id))
+            } else {
+                smallvec![trait_id.module(db.upcast()).krate()]
+            })
         }
-        TyKind::Dyn(_) => ty
-            .dyn_trait()
-            .and_then(|trait_| mod_to_crate_ids(GenericDefId::TraitId(trait_).module(db.upcast()))),
         // for primitives, there may be impls in various places (core and alloc
         // mostly). We just check the whole crate graph for crates with impls
         // (cached behind a query).
@@ -412,10 +429,11 @@ pub fn def_crates(
         | TyKind::Str
         | TyKind::Slice(_)
         | TyKind::Array(..)
-        | TyKind::Raw(..) => {
-            Some(db.inherent_impl_crates(cur_crate, fp.expect("fingerprint for primitive")))
-        }
-        _ => return None,
+        | TyKind::Raw(..) => Some(db.incoherent_inherent_impl_crates(
+            cur_crate,
+            TyFingerprint::for_inherent_impl(ty).expect("fingerprint for primitive"),
+        )),
+        _ => None,
     }
 }
 
@@ -470,14 +488,15 @@ pub fn lang_names_for_bin_op(op: syntax::ast::BinaryOp) -> Option<(Name, Name)>
 
 /// Look up the method with the given name.
 pub(crate) fn lookup_method(
-    ty: &Canonical<Ty>,
     db: &dyn HirDatabase,
+    ty: &Canonical<Ty>,
     env: Arc<TraitEnvironment>,
     traits_in_scope: &FxHashSet<TraitId>,
     visible_from_module: VisibleFromModule,
     name: &Name,
-) -> Option<(ReceiverAdjustments, FunctionId)> {
-    iterate_method_candidates(
+) -> Option<(ReceiverAdjustments, FunctionId, bool)> {
+    let mut not_visible = None;
+    let res = iterate_method_candidates(
         ty,
         db,
         env,
@@ -485,11 +504,16 @@ pub(crate) fn lookup_method(
         visible_from_module,
         Some(name),
         LookupMode::MethodCall,
-        |adjustments, f| match f {
-            AssocItemId::FunctionId(f) => Some((adjustments, f)),
+        |adjustments, f, visible| match f {
+            AssocItemId::FunctionId(f) if visible => Some((adjustments, f, true)),
+            AssocItemId::FunctionId(f) if not_visible.is_none() => {
+                not_visible = Some((adjustments, f, false));
+                None
+            }
             _ => None,
         },
-    )
+    );
+    res.or(not_visible)
 }
 
 /// Whether we're looking up a dotted method call (like `v.len()`) or a path
@@ -601,7 +625,7 @@ pub(crate) fn iterate_method_candidates<T>(
     visible_from_module: VisibleFromModule,
     name: Option<&Name>,
     mode: LookupMode,
-    mut callback: impl FnMut(ReceiverAdjustments, AssocItemId) -> Option<T>,
+    mut callback: impl FnMut(ReceiverAdjustments, AssocItemId, bool) -> Option<T>,
 ) -> Option<T> {
     let mut slot = None;
     iterate_method_candidates_dyn(
@@ -612,9 +636,9 @@ pub(crate) fn iterate_method_candidates<T>(
         visible_from_module,
         name,
         mode,
-        &mut |adj, item| {
+        &mut |adj, item, visible| {
             assert!(slot.is_none());
-            if let Some(it) = callback(adj, item) {
+            if let Some(it) = callback(adj, item, visible) {
                 slot = Some(it);
                 return ControlFlow::Break(());
             }
@@ -624,6 +648,30 @@ pub(crate) fn iterate_method_candidates<T>(
     slot
 }
 
+pub fn lookup_impl_const(
+    db: &dyn HirDatabase,
+    env: Arc<TraitEnvironment>,
+    const_id: ConstId,
+    subs: Substitution,
+) -> ConstId {
+    let trait_id = match const_id.lookup(db.upcast()).container {
+        ItemContainerId::TraitId(id) => id,
+        _ => return const_id,
+    };
+    let substitution = Substitution::from_iter(Interner, subs.iter(Interner));
+    let trait_ref = TraitRef { trait_id: to_chalk_trait_id(trait_id), substitution };
+
+    let const_data = db.const_data(const_id);
+    let name = match const_data.name.as_ref() {
+        Some(name) => name,
+        None => return const_id,
+    };
+
+    lookup_impl_assoc_item_for_trait_ref(trait_ref, db, env, name)
+        .and_then(|assoc| if let AssocItemId::ConstId(id) = assoc { Some(id) } else { None })
+        .unwrap_or(const_id)
+}
+
 /// Looks up the impl method that actually runs for the trait method `func`.
 ///
 /// Returns `func` if it's not a method defined in a trait or the lookup failed.
@@ -645,15 +693,17 @@ pub fn lookup_impl_method(
     };
 
     let name = &db.function_data(func).name;
-    lookup_impl_method_for_trait_ref(trait_ref, db, env, name).unwrap_or(func)
+    lookup_impl_assoc_item_for_trait_ref(trait_ref, db, env, name)
+        .and_then(|assoc| if let AssocItemId::FunctionId(id) = assoc { Some(id) } else { None })
+        .unwrap_or(func)
 }
 
-fn lookup_impl_method_for_trait_ref(
+fn lookup_impl_assoc_item_for_trait_ref(
     trait_ref: TraitRef,
     db: &dyn HirDatabase,
     env: Arc<TraitEnvironment>,
     name: &Name,
-) -> Option<FunctionId> {
+) -> Option<AssocItemId> {
     let self_ty = trait_ref.self_type_parameter(Interner);
     let self_ty_fp = TyFingerprint::for_trait_impl(&self_ty)?;
     let impls = db.trait_impls_in_deps(env.krate);
@@ -663,7 +713,15 @@ fn lookup_impl_method_for_trait_ref(
 
     let impl_data = find_matching_impl(impls, table, trait_ref)?;
     impl_data.items.iter().find_map(|it| match it {
-        AssocItemId::FunctionId(f) => (db.function_data(*f).name == *name).then(|| *f),
+        AssocItemId::FunctionId(f) => {
+            (db.function_data(*f).name == *name).then_some(AssocItemId::FunctionId(*f))
+        }
+        AssocItemId::ConstId(c) => db
+            .const_data(*c)
+            .name
+            .as_ref()
+            .map(|n| *n == *name)
+            .and_then(|result| if result { Some(AssocItemId::ConstId(*c)) } else { None }),
         _ => None,
     })
 }
@@ -719,7 +777,7 @@ pub fn iterate_path_candidates(
         name,
         LookupMode::Path,
         // the adjustments are not relevant for path lookup
-        &mut |_, id| callback(id),
+        &mut |_, id, _| callback(id),
     )
 }
 
@@ -731,7 +789,7 @@ pub fn iterate_method_candidates_dyn(
     visible_from_module: VisibleFromModule,
     name: Option<&Name>,
     mode: LookupMode,
-    callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+    callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
 ) -> ControlFlow<()> {
     match mode {
         LookupMode::MethodCall => {
@@ -795,7 +853,7 @@ fn iterate_method_candidates_with_autoref(
     traits_in_scope: &FxHashSet<TraitId>,
     visible_from_module: VisibleFromModule,
     name: Option<&Name>,
-    mut callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+    mut callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
 ) -> ControlFlow<()> {
     if receiver_ty.value.is_general_var(Interner, &receiver_ty.binders) {
         // don't try to resolve methods on unknown types
@@ -856,7 +914,7 @@ fn iterate_method_candidates_by_receiver(
     traits_in_scope: &FxHashSet<TraitId>,
     visible_from_module: VisibleFromModule,
     name: Option<&Name>,
-    mut callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+    mut callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
 ) -> ControlFlow<()> {
     let mut table = InferenceTable::new(db, env);
     let receiver_ty = table.instantiate_canonical(receiver_ty.clone());
@@ -868,7 +926,7 @@ fn iterate_method_candidates_by_receiver(
     while let Some((self_ty, _)) = autoderef.next() {
         iterate_inherent_methods(
             &self_ty,
-            &mut autoderef.table,
+            autoderef.table,
             name,
             Some(&receiver_ty),
             Some(receiver_adjustments.clone()),
@@ -883,7 +941,7 @@ fn iterate_method_candidates_by_receiver(
     while let Some((self_ty, _)) = autoderef.next() {
         iterate_trait_method_candidates(
             &self_ty,
-            &mut autoderef.table,
+            autoderef.table,
             traits_in_scope,
             name,
             Some(&receiver_ty),
@@ -902,7 +960,7 @@ fn iterate_method_candidates_for_self_ty(
     traits_in_scope: &FxHashSet<TraitId>,
     visible_from_module: VisibleFromModule,
     name: Option<&Name>,
-    mut callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+    mut callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
 ) -> ControlFlow<()> {
     let mut table = InferenceTable::new(db, env);
     let self_ty = table.instantiate_canonical(self_ty.clone());
@@ -933,7 +991,7 @@ fn iterate_trait_method_candidates(
     name: Option<&Name>,
     receiver_ty: Option<&Ty>,
     receiver_adjustments: Option<ReceiverAdjustments>,
-    callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+    callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
 ) -> ControlFlow<()> {
     let db = table.db;
     let env = table.trait_env.clone();
@@ -964,9 +1022,11 @@ fn iterate_trait_method_candidates(
         for &(_, item) in data.items.iter() {
             // Don't pass a `visible_from_module` down to `is_valid_candidate`,
             // since only inherent methods should be included into visibility checking.
-            if !is_valid_candidate(table, name, receiver_ty, item, self_ty, None) {
-                continue;
-            }
+            let visible = match is_valid_candidate(table, name, receiver_ty, item, self_ty, None) {
+                IsValidCandidate::Yes => true,
+                IsValidCandidate::NotVisible => false,
+                IsValidCandidate::No => continue,
+            };
             if !known_implemented {
                 let goal = generic_implements_goal(db, env.clone(), t, &canonical_self_ty);
                 if db.trait_solve(env.krate, goal.cast(Interner)).is_none() {
@@ -974,7 +1034,7 @@ fn iterate_trait_method_candidates(
                 }
             }
             known_implemented = true;
-            callback(receiver_adjustments.clone().unwrap_or_default(), item)?;
+            callback(receiver_adjustments.clone().unwrap_or_default(), item, visible)?;
         }
     }
     ControlFlow::Continue(())
@@ -987,7 +1047,7 @@ fn iterate_inherent_methods(
     receiver_ty: Option<&Ty>,
     receiver_adjustments: Option<ReceiverAdjustments>,
     visible_from_module: VisibleFromModule,
-    callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+    callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
 ) -> ControlFlow<()> {
     let db = table.db;
     let env = table.trait_env.clone();
@@ -1076,7 +1136,7 @@ fn iterate_inherent_methods(
         name: Option<&Name>,
         receiver_ty: Option<&Ty>,
         receiver_adjustments: Option<ReceiverAdjustments>,
-        callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+        callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
         traits: impl Iterator<Item = TraitId>,
     ) -> ControlFlow<()> {
         let db = table.db;
@@ -1084,9 +1144,13 @@ fn iterate_inherent_methods(
             let data = db.trait_data(t);
             for &(_, item) in data.items.iter() {
                 // We don't pass `visible_from_module` as all trait items should be visible.
-                if is_valid_candidate(table, name, receiver_ty, item, self_ty, None) {
-                    callback(receiver_adjustments.clone().unwrap_or_default(), item)?;
-                }
+                let visible =
+                    match is_valid_candidate(table, name, receiver_ty, item, self_ty, None) {
+                        IsValidCandidate::Yes => true,
+                        IsValidCandidate::NotVisible => false,
+                        IsValidCandidate::No => continue,
+                    };
+                callback(receiver_adjustments.clone().unwrap_or_default(), item, visible)?;
             }
         }
         ControlFlow::Continue(())
@@ -1100,17 +1164,25 @@ fn iterate_inherent_methods(
         receiver_ty: Option<&Ty>,
         receiver_adjustments: Option<ReceiverAdjustments>,
         visible_from_module: Option<ModuleId>,
-        callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId) -> ControlFlow<()>,
+        callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
     ) -> ControlFlow<()> {
         let db = table.db;
         let impls_for_self_ty = impls.for_self_ty(self_ty);
         for &impl_def in impls_for_self_ty {
             for &item in &db.impl_data(impl_def).items {
-                if !is_valid_candidate(table, name, receiver_ty, item, self_ty, visible_from_module)
-                {
-                    continue;
-                }
-                callback(receiver_adjustments.clone().unwrap_or_default(), item)?;
+                let visible = match is_valid_candidate(
+                    table,
+                    name,
+                    receiver_ty,
+                    item,
+                    self_ty,
+                    visible_from_module,
+                ) {
+                    IsValidCandidate::Yes => true,
+                    IsValidCandidate::NotVisible => false,
+                    IsValidCandidate::No => continue,
+                };
+                callback(receiver_adjustments.clone().unwrap_or_default(), item, visible)?;
             }
         }
         ControlFlow::Continue(())
@@ -1139,7 +1211,7 @@ pub fn resolve_indexing_op(
 macro_rules! check_that {
     ($cond:expr) => {
         if !$cond {
-            return false;
+            return IsValidCandidate::No;
         }
     };
 }
@@ -1151,7 +1223,7 @@ fn is_valid_candidate(
     item: AssocItemId,
     self_ty: &Ty,
     visible_from_module: Option<ModuleId>,
-) -> bool {
+) -> IsValidCandidate {
     let db = table.db;
     match item {
         AssocItemId::FunctionId(m) => {
@@ -1162,31 +1234,37 @@ fn is_valid_candidate(
             check_that!(receiver_ty.is_none());
 
             check_that!(name.map_or(true, |n| data.name.as_ref() == Some(n)));
-            check_that!(visible_from_module.map_or(true, |from_module| {
-                let v = db.const_visibility(c).is_visible_from(db.upcast(), from_module);
-                if !v {
+
+            if let Some(from_module) = visible_from_module {
+                if !db.const_visibility(c).is_visible_from(db.upcast(), from_module) {
                     cov_mark::hit!(const_candidate_not_visible);
+                    return IsValidCandidate::NotVisible;
                 }
-                v
-            }));
+            }
             if let ItemContainerId::ImplId(impl_id) = c.lookup(db.upcast()).container {
                 let self_ty_matches = table.run_in_snapshot(|table| {
                     let expected_self_ty = TyBuilder::impl_self_ty(db, impl_id)
                         .fill_with_inference_vars(table)
                         .build();
-                    table.unify(&expected_self_ty, &self_ty)
+                    table.unify(&expected_self_ty, self_ty)
                 });
                 if !self_ty_matches {
                     cov_mark::hit!(const_candidate_self_type_mismatch);
-                    return false;
+                    return IsValidCandidate::No;
                 }
             }
-            true
+            IsValidCandidate::Yes
         }
-        _ => false,
+        _ => IsValidCandidate::No,
     }
 }
 
+enum IsValidCandidate {
+    Yes,
+    No,
+    NotVisible,
+}
+
 fn is_valid_fn_candidate(
     table: &mut InferenceTable<'_>,
     fn_id: FunctionId,
@@ -1194,19 +1272,17 @@ fn is_valid_fn_candidate(
     receiver_ty: Option<&Ty>,
     self_ty: &Ty,
     visible_from_module: Option<ModuleId>,
-) -> bool {
+) -> IsValidCandidate {
     let db = table.db;
     let data = db.function_data(fn_id);
 
     check_that!(name.map_or(true, |n| n == &data.name));
-    check_that!(visible_from_module.map_or(true, |from_module| {
-        let v = db.function_visibility(fn_id).is_visible_from(db.upcast(), from_module);
-        if !v {
+    if let Some(from_module) = visible_from_module {
+        if !db.function_visibility(fn_id).is_visible_from(db.upcast(), from_module) {
             cov_mark::hit!(autoderef_candidate_not_visible);
+            return IsValidCandidate::NotVisible;
         }
-        v
-    }));
-
+    }
     table.run_in_snapshot(|table| {
         let container = fn_id.lookup(db.upcast()).container;
         let (impl_subst, expect_self_ty) = match container {
@@ -1245,7 +1321,7 @@ fn is_valid_fn_candidate(
             // We need to consider the bounds on the impl to distinguish functions of the same name
             // for a type.
             let predicates = db.generic_predicates(impl_id.into());
-            predicates
+            let valid = predicates
                 .iter()
                 .map(|predicate| {
                     let (p, b) = predicate
@@ -1260,12 +1336,16 @@ fn is_valid_fn_candidate(
                 // It's ok to get ambiguity here, as we may not have enough information to prove
                 // obligations. We'll check if the user is calling the selected method properly
                 // later anyway.
-                .all(|p| table.try_obligation(p.cast(Interner)).is_some())
+                .all(|p| table.try_obligation(p.cast(Interner)).is_some());
+            match valid {
+                true => IsValidCandidate::Yes,
+                false => IsValidCandidate::No,
+            }
         } else {
             // For `ItemContainerId::TraitId`, we check if `self_ty` implements the trait in
             // `iterate_trait_method_candidates()`.
             // For others, this function shouldn't be called.
-            true
+            IsValidCandidate::Yes
         }
     })
 }

crates/hir-ty/src/tests.rs

@@ -94,18 +94,19 @@ fn check_impl(ra_fixture: &str, allow_none: bool, only_types: bool, display_sour
                 types.insert(file_range, expected.trim_start_matches("type: ").to_string());
             } else if expected.starts_with("expected") {
                 mismatches.insert(file_range, expected);
-            } else if expected.starts_with("adjustments: ") {
+            } else if expected.starts_with("adjustments:") {
                 adjustments.insert(
                     file_range,
                     expected
-                        .trim_start_matches("adjustments: ")
+                        .trim_start_matches("adjustments:")
+                        .trim()
                         .split(',')
                         .map(|it| it.trim().to_string())
                         .filter(|it| !it.is_empty())
                         .collect(),
                 );
             } else {
-                panic!("unexpected annotation: {}", expected);
+                panic!("unexpected annotation: {expected}");
             }
             had_annotations = true;
         }
@@ -176,17 +177,17 @@ fn check_impl(ra_fixture: &str, allow_none: bool, only_types: bool, display_sour
                 assert_eq!(actual, expected);
             }
             if let Some(expected) = adjustments.remove(&range) {
-                if let Some(adjustments) = inference_result.expr_adjustments.get(&expr) {
-                    assert_eq!(
-                        expected,
-                        adjustments
-                            .iter()
-                            .map(|Adjustment { kind, .. }| format!("{:?}", kind))
-                            .collect::<Vec<_>>()
-                    );
-                } else {
-                    panic!("expected {:?} adjustments, found none", expected);
-                }
+                let adjustments = inference_result
+                    .expr_adjustments
+                    .get(&expr)
+                    .map_or_else(Default::default, |it| &**it);
+                assert_eq!(
+                    expected,
+                    adjustments
+                        .iter()
+                        .map(|Adjustment { kind, .. }| format!("{kind:?}"))
+                        .collect::<Vec<_>>()
+                );
             }
         }
 

crates/hir-ty/src/tests/coercion.rs

@@ -807,3 +807,37 @@ fn main() {
         "#,
     );
 }
+
+#[test]
+fn adjust_comparison_arguments() {
+    check_no_mismatches(
+        r"
+//- minicore: eq
+struct Struct;
+impl core::cmp::PartialEq for Struct {
+    fn eq(&self, other: &Self) -> bool { true }
+}
+fn test() {
+    Struct == Struct;
+ // ^^^^^^ adjustments: Borrow(Ref(Not))
+           // ^^^^^^ adjustments: Borrow(Ref(Not))
+}",
+    );
+}
+
+#[test]
+fn adjust_assign_lhs() {
+    check_no_mismatches(
+        r"
+//- minicore: add
+struct Struct;
+impl core::ops::AddAssign for Struct {
+    fn add_assign(&mut self, other: Self) {}
+}
+fn test() {
+    Struct += Struct;
+ // ^^^^^^ adjustments: Borrow(Ref(Mut))
+           // ^^^^^^ adjustments:
+}",
+    );
+}

crates/hir-ty/src/tests/incremental.rs

@@ -24,7 +24,7 @@ fn typing_whitespace_inside_a_function_should_not_invalidate_types() {
                 db.infer(def);
             });
         });
-        assert!(format!("{:?}", events).contains("infer"))
+        assert!(format!("{events:?}").contains("infer"))
     }
 
     let new_text = "
@@ -46,6 +46,6 @@ fn typing_whitespace_inside_a_function_should_not_invalidate_types() {
                 db.infer(def);
             });
         });
-        assert!(!format!("{:?}", events).contains("infer"), "{:#?}", events)
+        assert!(!format!("{events:?}").contains("infer"), "{events:#?}")
     }
 }

crates/hir-ty/src/tests/macros.rs

@@ -849,7 +849,7 @@ fn main() {
   //^^^^^^^^^^^^^^^^^ RegisterBlock
 }
     "#;
-    let fixture = format!("{}\n//- /foo.rs\n{}", fixture, data);
+    let fixture = format!("{fixture}\n//- /foo.rs\n{data}");
 
     {
         let _b = bench("include macro");

crates/hir-ty/src/tests/method_resolution.rs

@@ -1867,3 +1867,53 @@ fn g<T: Trait>(a: T) {
         "#,
     );
 }
+
+#[test]
+fn incoherent_impls() {
+    check(
+        r#"
+//- minicore: error, send
+pub struct Box<T>(T);
+use core::error::Error;
+
+#[rustc_allow_incoherent_impl]
+impl dyn Error {
+    pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error>> {
+        loop {}
+    }
+}
+#[rustc_allow_incoherent_impl]
+impl dyn Error + Send {
+    /// Attempts to downcast the box to a concrete type.
+    pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error + Send>> {
+        let err: Box<dyn Error> = self;
+                               // ^^^^ expected Box<dyn Error>, got Box<dyn Error + Send>
+                               // FIXME, type mismatch should not occur
+        <dyn Error>::downcast(err).map_err(|_| loop {})
+      //^^^^^^^^^^^^^^^^^^^^^ type: fn downcast<{unknown}>(Box<dyn Error>) -> Result<Box<{unknown}>, Box<dyn Error>>
+    }
+}
+"#,
+    );
+}
+
+#[test]
+fn fallback_private_methods() {
+    check(
+        r#"
+mod module {
+    pub struct Struct;
+
+    impl Struct {
+        fn func(&self) {}
+    }
+}
+
+fn foo() {
+    let s = module::Struct;
+    s.func();
+  //^^^^^^^^ type: ()
+}
+"#,
+    );
+}

crates/hir-ty/src/tests/patterns.rs

@@ -1080,3 +1080,15 @@ fn my_fn(#[cfg(feature = "feature")] u8: u8, u32: u32) {}
 "#,
     );
 }
+
+#[test]
+fn var_args() {
+    check_types(
+        r#"
+#[lang = "va_list"]
+pub struct VaListImpl<'f>;
+fn my_fn(foo: ...) {}
+       //^^^ VaListImpl
+"#,
+    );
+}

crates/hir-ty/src/tests/regression.rs

@@ -1723,3 +1723,24 @@ fn bar() -> ControlFlow<(), ()> {
 "#,
     );
 }
+
+#[test]
+fn assoc_type_shorthand_with_gats_in_binders() {
+    // c.f. test `issue_4885()`
+    check_no_mismatches(
+        r#"
+trait Gats {
+    type Assoc<T>;
+}
+trait Foo<T> {}
+
+struct Bar<'a, B: Gats, A> {
+    field: &'a dyn Foo<B::Assoc<A>>,
+}
+
+fn foo(b: Bar) {
+    let _ = b.field;
+}
+"#,
+    );
+}

crates/hir-ty/src/tests/simple.rs

@@ -2064,17 +2064,17 @@ fn fn_pointer_return() {
 fn block_modifiers_smoke_test() {
     check_infer(
         r#"
-//- minicore: future
+//- minicore: future, try
 async fn main() {
     let x = unsafe { 92 };
     let y = async { async { () }.await };
-    let z = try { () };
+    let z: core::ops::ControlFlow<(), _> = try { () };
     let w = const { 92 };
     let t = 'a: { 92 };
 }
         "#,
         expect![[r#"
-            16..162 '{     ...2 }; }': ()
+            16..193 '{     ...2 }; }': ()
             26..27 'x': i32
             30..43 'unsafe { 92 }': i32
             30..43 'unsafe { 92 }': i32
@@ -2086,17 +2086,17 @@ async fn main() {
             65..77 'async { () }': impl Future<Output = ()>
             65..83 'async ....await': ()
             73..75 '()': ()
-            95..96 'z': {unknown}
-            99..109 'try { () }': ()
-            99..109 'try { () }': {unknown}
-            105..107 '()': ()
-            119..120 'w': i32
-            123..135 'const { 92 }': i32
-            123..135 'const { 92 }': i32
-            131..133 '92': i32
-            145..146 't': i32
-            149..159 ''a: { 92 }': i32
-            155..157 '92': i32
+            95..96 'z': ControlFlow<(), ()>
+            130..140 'try { () }': ()
+            130..140 'try { () }': ControlFlow<(), ()>
+            136..138 '()': ()
+            150..151 'w': i32
+            154..166 'const { 92 }': i32
+            154..166 'const { 92 }': i32
+            162..164 '92': i32
+            176..177 't': i32
+            180..190 ''a: { 92 }': i32
+            186..188 '92': i32
         "#]],
     )
 }

crates/hir-ty/src/tests/traits.rs

@@ -1388,6 +1388,22 @@ fn foo<const C: u8, T>() -> (impl FnOnce(&str, T), impl Trait<u8>) {
     );
 }
 
+#[test]
+fn return_pos_impl_trait_in_projection() {
+    // Note that the unused type param `X` is significant; see #13307.
+    check_no_mismatches(
+        r#"
+//- minicore: sized
+trait Future { type Output; }
+impl Future for () { type Output = i32; }
+type Foo<F> = (<F as Future>::Output, F);
+fn foo<X>() -> Foo<impl Future<Output = ()>> {
+    (0, ())
+}
+"#,
+    )
+}
+
 #[test]
 fn dyn_trait() {
     check_infer(
@@ -4084,3 +4100,68 @@ where
     "#,
     );
 }
+
+#[test]
+fn bin_op_with_scalar_fallback() {
+    // Extra impls are significant so that chalk doesn't give us definite guidances.
+    check_types(
+        r#"
+//- minicore: add
+use core::ops::Add;
+
+struct Vec2<T>(T, T);
+
+impl Add for Vec2<i32> {
+    type Output = Self;
+    fn add(self, rhs: Self) -> Self::Output { loop {} }
+}
+impl Add for Vec2<u32> {
+    type Output = Self;
+    fn add(self, rhs: Self) -> Self::Output { loop {} }
+}
+impl Add for Vec2<f32> {
+    type Output = Self;
+    fn add(self, rhs: Self) -> Self::Output { loop {} }
+}
+impl Add for Vec2<f64> {
+    type Output = Self;
+    fn add(self, rhs: Self) -> Self::Output { loop {} }
+}
+
+fn test() {
+    let a = Vec2(1, 2);
+    let b = Vec2(3, 4);
+    let c = a + b;
+      //^ Vec2<i32>
+    let a = Vec2(1., 2.);
+    let b = Vec2(3., 4.);
+    let c = a + b;
+      //^ Vec2<f64>
+}
+"#,
+    );
+}
+
+#[test]
+fn trait_method_with_scalar_fallback() {
+    check_types(
+        r#"
+trait Trait {
+    type Output;
+    fn foo(&self) -> Self::Output;
+}
+impl<T> Trait for T {
+    type Output = T;
+    fn foo(&self) -> Self::Output { loop {} }
+}
+fn test() {
+    let a = 42;
+    let b = a.foo();
+      //^ i32
+    let a = 3.14;
+    let b = a.foo();
+      //^ f64
+}
+"#,
+    );
+}

crates/hir-ty/src/tls.rs

@@ -67,12 +67,12 @@ impl DebugContext<'_> {
         let trait_ref = projection_ty.trait_ref(self.0);
         let trait_params = trait_ref.substitution.as_slice(Interner);
         let self_ty = trait_ref.self_type_parameter(Interner);
-        write!(fmt, "<{:?} as {}", self_ty, trait_name)?;
+        write!(fmt, "<{self_ty:?} as {trait_name}")?;
         if trait_params.len() > 1 {
             write!(
                 fmt,
                 "<{}>",
-                trait_params[1..].iter().format_with(", ", |x, f| f(&format_args!("{:?}", x))),
+                trait_params[1..].iter().format_with(", ", |x, f| f(&format_args!("{x:?}"))),
             )?;
         }
         write!(fmt, ">::{}", type_alias_data.name)?;
@@ -83,7 +83,7 @@ impl DebugContext<'_> {
             write!(
                 fmt,
                 "<{}>",
-                proj_params.iter().format_with(", ", |x, f| f(&format_args!("{:?}", x))),
+                proj_params.iter().format_with(", ", |x, f| f(&format_args!("{x:?}"))),
             )?;
         }
 
@@ -105,9 +105,9 @@ impl DebugContext<'_> {
             }
         };
         match def {
-            CallableDefId::FunctionId(_) => write!(fmt, "{{fn {}}}", name),
+            CallableDefId::FunctionId(_) => write!(fmt, "{{fn {name}}}"),
             CallableDefId::StructId(_) | CallableDefId::EnumVariantId(_) => {
-                write!(fmt, "{{ctor {}}}", name)
+                write!(fmt, "{{ctor {name}}}")
             }
         }
     }

crates/hir-ty/src/traits.rs

@@ -18,7 +18,7 @@ use crate::{
 };
 
 /// This controls how much 'time' we give the Chalk solver before giving up.
-const CHALK_SOLVER_FUEL: i32 = 100;
+const CHALK_SOLVER_FUEL: i32 = 1000;
 
 #[derive(Debug, Copy, Clone)]
 pub(crate) struct ChalkContext<'a> {
@@ -55,13 +55,10 @@ impl TraitEnvironment {
         }
     }
 
-    pub fn traits_in_scope_from_clauses<'a>(
-        &'a self,
-        ty: Ty,
-    ) -> impl Iterator<Item = TraitId> + 'a {
+    pub fn traits_in_scope_from_clauses(&self, ty: Ty) -> impl Iterator<Item = TraitId> + '_ {
         self.traits_from_clauses
             .iter()
-            .filter_map(move |(self_ty, trait_id)| (*self_ty == ty).then(|| *trait_id))
+            .filter_map(move |(self_ty, trait_id)| (*self_ty == ty).then_some(*trait_id))
     }
 }
 
@@ -130,7 +127,7 @@ fn solve(
 
     let mut solve = || {
         let _ctx = if is_chalk_debug() || is_chalk_print() {
-            Some(panic_context::enter(format!("solving {:?}", goal)))
+            Some(panic_context::enter(format!("solving {goal:?}")))
         } else {
             None
         };

crates/hir-ty/src/utils.rs

@@ -17,7 +17,7 @@ use hir_def::{
     ConstParamId, FunctionId, GenericDefId, ItemContainerId, Lookup, TraitId, TypeAliasId,
     TypeOrConstParamId, TypeParamId,
 };
-use hir_expand::name::{known, Name};
+use hir_expand::name::Name;
 use itertools::Either;
 use rustc_hash::FxHashSet;
 use smallvec::{smallvec, SmallVec};
@@ -184,9 +184,7 @@ pub(crate) struct Generics {
 }
 
 impl Generics {
-    pub(crate) fn iter_id<'a>(
-        &'a self,
-    ) -> impl Iterator<Item = Either<TypeParamId, ConstParamId>> + 'a {
+    pub(crate) fn iter_id(&self) -> impl Iterator<Item = Either<TypeParamId, ConstParamId>> + '_ {
         self.iter().map(|(id, data)| match data {
             TypeOrConstParamData::TypeParamData(_) => Either::Left(TypeParamId::from_unchecked(id)),
             TypeOrConstParamData::ConstParamData(_) => {
@@ -216,9 +214,9 @@ impl Generics {
     }
 
     /// Iterator over types and const params of parent.
-    pub(crate) fn iter_parent<'a>(
-        &'a self,
-    ) -> impl DoubleEndedIterator<Item = (TypeOrConstParamId, &'a TypeOrConstParamData)> + 'a {
+    pub(crate) fn iter_parent(
+        &self,
+    ) -> impl DoubleEndedIterator<Item = (TypeOrConstParamId, &TypeOrConstParamData)> {
         self.parent_generics().into_iter().flat_map(|it| {
             let to_toc_id =
                 move |(local_id, p)| (TypeOrConstParamId { parent: it.def, local_id }, p);
@@ -335,54 +333,18 @@ pub fn is_fn_unsafe_to_call(db: &dyn HirDatabase, func: FunctionId) -> bool {
             // Function in an `extern` block are always unsafe to call, except when it has
             // `"rust-intrinsic"` ABI there are a few exceptions.
             let id = block.lookup(db.upcast()).id;
-            !matches!(
-                id.item_tree(db.upcast())[id.value].abi.as_deref(),
-                Some("rust-intrinsic") if !is_intrinsic_fn_unsafe(&data.name)
-            )
+
+            let is_intrinsic =
+                id.item_tree(db.upcast())[id.value].abi.as_deref() == Some("rust-intrinsic");
+
+            if is_intrinsic {
+                // Intrinsics are unsafe unless they have the rustc_safe_intrinsic attribute
+                !data.attrs.by_key("rustc_safe_intrinsic").exists()
+            } else {
+                // Extern items are always unsafe
+                true
+            }
         }
         _ => false,
     }
 }
-
-/// Returns `true` if the given intrinsic is unsafe to call, or false otherwise.
-fn is_intrinsic_fn_unsafe(name: &Name) -> bool {
-    // Should be kept in sync with https://github.com/rust-lang/rust/blob/532d2b14c05f9bc20b2d27cbb5f4550d28343a36/compiler/rustc_typeck/src/check/intrinsic.rs#L72-L106
-    ![
-        known::abort,
-        known::add_with_overflow,
-        known::bitreverse,
-        known::black_box,
-        known::bswap,
-        known::caller_location,
-        known::ctlz,
-        known::ctpop,
-        known::cttz,
-        known::discriminant_value,
-        known::forget,
-        known::likely,
-        known::maxnumf32,
-        known::maxnumf64,
-        known::min_align_of,
-        known::minnumf32,
-        known::minnumf64,
-        known::mul_with_overflow,
-        known::needs_drop,
-        known::ptr_guaranteed_eq,
-        known::ptr_guaranteed_ne,
-        known::rotate_left,
-        known::rotate_right,
-        known::rustc_peek,
-        known::saturating_add,
-        known::saturating_sub,
-        known::size_of,
-        known::sub_with_overflow,
-        known::type_id,
-        known::type_name,
-        known::unlikely,
-        known::variant_count,
-        known::wrapping_add,
-        known::wrapping_mul,
-        known::wrapping_sub,
-    ]
-    .contains(name)
-}