feat: IDE features for primitive tuple fields

crates/hir-def/src/lib.rs

@@ -307,6 +307,15 @@ pub struct FieldId {
 
 pub type LocalFieldId = Idx<data::adt::FieldData>;
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct TupleId(pub u32);
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct TupleFieldId {
+    pub tuple: TupleId,
+    pub index: u32,
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct ConstId(salsa::InternId);
 type ConstLoc = AssocItemLoc<Const>;

crates/hir-ty/Cargo.toml

@@ -32,6 +32,7 @@ once_cell = "1.17.0"
 triomphe.workspace = true
 nohash-hasher.workspace = true
 typed-arena = "2.0.1"
+indexmap.workspace = true
 
 rustc-dependencies.workspace = true
 
@@ -60,4 +61,4 @@ test-fixture.workspace = true
 in-rust-tree = ["rustc-dependencies/in-rust-tree"]
 
 [lints]
-workspace = true
+workspace = true

crates/hir-ty/src/infer.rs

@@ -41,9 +41,10 @@ use hir_def::{
     resolver::{HasResolver, ResolveValueResult, Resolver, TypeNs, ValueNs},
     type_ref::TypeRef,
     AdtId, AssocItemId, DefWithBodyId, EnumVariantId, FieldId, FunctionId, ItemContainerId, Lookup,
-    TraitId, TypeAliasId, VariantId,
+    TraitId, TupleFieldId, TupleId, TypeAliasId, VariantId,
 };
 use hir_expand::name::{name, Name};
+use indexmap::IndexSet;
 use la_arena::{ArenaMap, Entry};
 use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::{always, never};
@@ -403,11 +404,15 @@ pub struct InferenceResult {
     /// For each method call expr, records the function it resolves to.
     method_resolutions: FxHashMap<ExprId, (FunctionId, Substitution)>,
     /// For each field access expr, records the field it resolves to.
-    field_resolutions: FxHashMap<ExprId, FieldId>,
+    field_resolutions: FxHashMap<ExprId, Either<FieldId, TupleFieldId>>,
     /// 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, Substitution)>,
+    /// Whenever a tuple field expression access a tuple field, we allocate a tuple id in
+    /// [`InferenceContext`] and store the tuples substitution there. This map is the reverse of
+    /// that which allows us to resolve a [`TupleFieldId`]s type.
+    pub tuple_field_access_types: FxHashMap<TupleId, Substitution>,
     pub diagnostics: Vec<InferenceDiagnostic>,
     pub type_of_expr: ArenaMap<ExprId, Ty>,
     /// For each pattern record the type it resolves to.
@@ -447,7 +452,7 @@ impl InferenceResult {
     pub fn method_resolution(&self, expr: ExprId) -> Option<(FunctionId, Substitution)> {
         self.method_resolutions.get(&expr).cloned()
     }
-    pub fn field_resolution(&self, expr: ExprId) -> Option<FieldId> {
+    pub fn field_resolution(&self, expr: ExprId) -> Option<Either<FieldId, TupleFieldId>> {
         self.field_resolutions.get(&expr).copied()
     }
     pub fn variant_resolution_for_expr(&self, id: ExprId) -> Option<VariantId> {
@@ -517,6 +522,8 @@ pub(crate) struct InferenceContext<'a> {
     /// The traits in scope, disregarding block modules. This is used for caching purposes.
     traits_in_scope: FxHashSet<TraitId>,
     pub(crate) result: InferenceResult,
+    tuple_field_accesses_rev:
+        IndexSet<Substitution, std::hash::BuildHasherDefault<rustc_hash::FxHasher>>,
     /// The return type of the function being inferred, the closure or async block if we're
     /// currently within one.
     ///
@@ -598,6 +605,7 @@ impl<'a> InferenceContext<'a> {
         InferenceContext {
             result: InferenceResult::default(),
             table: unify::InferenceTable::new(db, trait_env),
+            tuple_field_accesses_rev: Default::default(),
             return_ty: TyKind::Error.intern(Interner), // set in collect_* calls
             resume_yield_tys: None,
             return_coercion: None,
@@ -621,7 +629,13 @@ impl<'a> InferenceContext<'a> {
     // used this function for another workaround, mention it here. If you really need this function and believe that
     // there is no problem in it being `pub(crate)`, remove this comment.
     pub(crate) fn resolve_all(self) -> InferenceResult {
-        let InferenceContext { mut table, mut result, deferred_cast_checks, .. } = self;
+        let InferenceContext {
+            mut table,
+            mut result,
+            deferred_cast_checks,
+            tuple_field_accesses_rev,
+            ..
+        } = self;
         // Destructure every single field so whenever new fields are added to `InferenceResult` we
         // don't forget to handle them here.
         let InferenceResult {
@@ -645,6 +659,7 @@ impl<'a> InferenceContext<'a> {
             // to resolve them here.
             closure_info: _,
             mutated_bindings_in_closure: _,
+            tuple_field_access_types: _,
         } = &mut result;
 
         table.fallback_if_possible();
@@ -720,6 +735,11 @@ impl<'a> InferenceContext<'a> {
         for adjustment in pat_adjustments.values_mut().flatten() {
             *adjustment = table.resolve_completely(adjustment.clone());
         }
+        result.tuple_field_access_types = tuple_field_accesses_rev
+            .into_iter()
+            .enumerate()
+            .map(|(idx, subst)| (TupleId(idx as u32), table.resolve_completely(subst.clone())))
+            .collect();
         result
     }
 

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

@@ -7,12 +7,13 @@ use chalk_ir::{
     fold::{FallibleTypeFolder, TypeFoldable},
     AliasEq, AliasTy, BoundVar, DebruijnIndex, FnSubst, Mutability, TyKind, WhereClause,
 };
+use either::Either;
 use hir_def::{
     data::adt::VariantData,
     hir::{Array, BinaryOp, BindingId, CaptureBy, Expr, ExprId, Pat, PatId, Statement, UnaryOp},
     lang_item::LangItem,
     resolver::{resolver_for_expr, ResolveValueResult, ValueNs},
-    DefWithBodyId, FieldId, HasModule, VariantId,
+    DefWithBodyId, FieldId, HasModule, TupleFieldId, TupleId, VariantId,
 };
 use hir_expand::name;
 use rustc_hash::FxHashMap;
@@ -186,7 +187,7 @@ impl CapturedItem {
                     result = format!("*{result}");
                     field_need_paren = true;
                 }
-                ProjectionElem::Field(f) => {
+                ProjectionElem::Field(Either::Left(f)) => {
                     if field_need_paren {
                         result = format!("({result})");
                     }
@@ -207,7 +208,15 @@ impl CapturedItem {
                     result = format!("{result}.{field}");
                     field_need_paren = false;
                 }
-                &ProjectionElem::TupleOrClosureField(field) => {
+                ProjectionElem::Field(Either::Right(f)) => {
+                    let field = f.index;
+                    if field_need_paren {
+                        result = format!("({result})");
+                    }
+                    result = format!("{result}.{field}");
+                    field_need_paren = false;
+                }
+                &ProjectionElem::ClosureField(field) => {
                     if field_need_paren {
                         result = format!("({result})");
                     }
@@ -329,15 +338,10 @@ impl InferenceContext<'_> {
                     }
                 }
             }
-            Expr::Field { expr, name } => {
+            Expr::Field { expr, name: _ } => {
                 let mut place = self.place_of_expr(*expr)?;
-                if let TyKind::Tuple(..) = self.expr_ty(*expr).kind(Interner) {
-                    let index = name.as_tuple_index()?;
-                    place.projections.push(ProjectionElem::TupleOrClosureField(index))
-                } else {
-                    let field = self.result.field_resolution(tgt_expr)?;
-                    place.projections.push(ProjectionElem::Field(field));
-                }
+                let field = self.result.field_resolution(tgt_expr)?;
+                place.projections.push(ProjectionElem::Field(field));
                 return Some(place);
             }
             Expr::UnaryOp { expr, op: UnaryOp::Deref } => {
@@ -825,7 +829,10 @@ impl InferenceContext<'_> {
                 let it = al.iter().zip(fields.clone()).chain(ar.iter().rev().zip(fields.rev()));
                 for (arg, i) in it {
                     let mut p = place.clone();
-                    p.projections.push(ProjectionElem::TupleOrClosureField(i));
+                    p.projections.push(ProjectionElem::Field(Either::Right(TupleFieldId {
+                        tuple: TupleId(!0), // dummy this, as its unused anyways
+                        index: i as u32,
+                    })));
                     self.consume_with_pat(p, *arg);
                 }
             }
@@ -850,10 +857,10 @@ impl InferenceContext<'_> {
                                 continue;
                             };
                             let mut p = place.clone();
-                            p.projections.push(ProjectionElem::Field(FieldId {
+                            p.projections.push(ProjectionElem::Field(Either::Left(FieldId {
                                 parent: variant.into(),
                                 local_id,
-                            }));
+                            })));
                             self.consume_with_pat(p, arg);
                         }
                     }
@@ -894,10 +901,10 @@ impl InferenceContext<'_> {
                             al.iter().zip(fields.clone()).chain(ar.iter().rev().zip(fields.rev()));
                         for (arg, (i, _)) in it {
                             let mut p = place.clone();
-                            p.projections.push(ProjectionElem::Field(FieldId {
+                            p.projections.push(ProjectionElem::Field(Either::Left(FieldId {
                                 parent: variant.into(),
                                 local_id: i,
-                            }));
+                            })));
                             self.consume_with_pat(p, *arg);
                         }
                     }

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

@@ -6,14 +6,15 @@ use std::{
 };
 
 use chalk_ir::{cast::Cast, fold::Shift, DebruijnIndex, Mutability, TyVariableKind};
+use either::Either;
 use hir_def::{
     generics::TypeOrConstParamData,
     hir::{
         ArithOp, Array, BinaryOp, ClosureKind, Expr, ExprId, LabelId, Literal, Statement, UnaryOp,
     },
     lang_item::{LangItem, LangItemTarget},
     path::{GenericArg, GenericArgs},
-    BlockId, ConstParamId, FieldId, ItemContainerId, Lookup,
+    BlockId, ConstParamId, FieldId, ItemContainerId, Lookup, TupleFieldId, TupleId,
 };
 use hir_expand::name::{name, Name};
 use stdx::always;
@@ -1406,7 +1407,7 @@ impl InferenceContext<'_> {
         &mut self,
         receiver_ty: &Ty,
         name: &Name,
-    ) -> Option<(Ty, Option<FieldId>, Vec<Adjustment>, bool)> {
+    ) -> Option<(Ty, Either<FieldId, TupleFieldId>, Vec<Adjustment>, bool)> {
         let mut autoderef = Autoderef::new(&mut self.table, receiver_ty.clone(), false);
         let mut private_field = None;
         let res = autoderef.by_ref().find_map(|(derefed_ty, _)| {
@@ -1418,7 +1419,20 @@ impl InferenceContext<'_> {
                             .get(idx)
                             .map(|a| a.assert_ty_ref(Interner))
                             .cloned()
-                            .map(|ty| (None, ty))
+                            .map(|ty| {
+                                (
+                                    Either::Right(TupleFieldId {
+                                        tuple: TupleId(
+                                            self.tuple_field_accesses_rev
+                                                .insert_full(substs.clone())
+                                                .0
+                                                as u32,
+                                        ),
+                                        index: idx as u32,
+                                    }),
+                                    ty,
+                                )
+                            })
                     });
                 }
                 TyKind::Adt(AdtId(hir_def::AdtId::StructId(s)), parameters) => {
@@ -1444,7 +1458,7 @@ impl InferenceContext<'_> {
             let ty = self.db.field_types(field_id.parent)[field_id.local_id]
                 .clone()
                 .substitute(Interner, &parameters);
-            Some((Some(field_id), ty))
+            Some((Either::Left(field_id), ty))
         });
 
         Some(match res {
@@ -1464,7 +1478,7 @@ impl InferenceContext<'_> {
                 let ty = self.insert_type_vars(ty);
                 let ty = self.normalize_associated_types_in(ty);
 
-                (ty, Some(field_id), adjustments, false)
+                (ty, Either::Left(field_id), adjustments, false)
             }
         })
     }
@@ -1487,11 +1501,9 @@ impl InferenceContext<'_> {
         match self.lookup_field(&receiver_ty, name) {
             Some((ty, field_id, adjustments, is_public)) => {
                 self.write_expr_adj(receiver, adjustments);
-                if let Some(field_id) = field_id {
-                    self.result.field_resolutions.insert(tgt_expr, field_id);
-                }
+                self.result.field_resolutions.insert(tgt_expr, field_id);
                 if !is_public {
-                    if let Some(field) = field_id {
+                    if let Either::Left(field) = field_id {
                         // FIXME: Merge this diagnostic into UnresolvedField?
                         self.result
                             .diagnostics
@@ -1581,9 +1593,7 @@ impl InferenceContext<'_> {
                 {
                     Some((ty, field_id, adjustments, _public)) => {
                         self.write_expr_adj(receiver, adjustments);
-                        if let Some(field_id) = field_id {
-                            self.result.field_resolutions.insert(tgt_expr, field_id);
-                        }
+                        self.result.field_resolutions.insert(tgt_expr, field_id);
                         Some(ty)
                     }
                     None => None,

crates/hir-ty/src/mir.rs

@@ -14,9 +14,10 @@ use crate::{
 };
 use base_db::CrateId;
 use chalk_ir::Mutability;
+use either::Either;
 use hir_def::{
     hir::{BindingId, Expr, ExprId, Ordering, PatId},
-    DefWithBodyId, FieldId, StaticId, UnionId, VariantId,
+    DefWithBodyId, FieldId, StaticId, TupleFieldId, UnionId, VariantId,
 };
 use la_arena::{Arena, ArenaMap, Idx, RawIdx};
 
@@ -124,9 +125,9 @@ impl Operand {
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum ProjectionElem<V, T> {
     Deref,
-    Field(FieldId),
+    Field(Either<FieldId, TupleFieldId>),
     // FIXME: get rid of this, and use FieldId for tuples and closures
-    TupleOrClosureField(usize),
+    ClosureField(usize),
     Index(V),
     ConstantIndex { offset: u64, from_end: bool },
     Subslice { from: u64, to: u64 },
@@ -161,7 +162,7 @@ impl<V, T> ProjectionElem<V, T> {
                     return TyKind::Error.intern(Interner);
                 }
             },
-            ProjectionElem::Field(f) => match &base.kind(Interner) {
+            ProjectionElem::Field(Either::Left(f)) => match &base.kind(Interner) {
                 TyKind::Adt(_, subst) => {
                     db.field_types(f.parent)[f.local_id].clone().substitute(Interner, subst)
                 }
@@ -170,19 +171,25 @@ impl<V, T> ProjectionElem<V, T> {
                     return TyKind::Error.intern(Interner);
                 }
             },
-            ProjectionElem::TupleOrClosureField(f) => match &base.kind(Interner) {
+            ProjectionElem::Field(Either::Right(f)) => match &base.kind(Interner) {
                 TyKind::Tuple(_, subst) => subst
                     .as_slice(Interner)
-                    .get(*f)
+                    .get(f.index as usize)
                     .map(|x| x.assert_ty_ref(Interner))
                     .cloned()
                     .unwrap_or_else(|| {
                         never!("Out of bound tuple field");
                         TyKind::Error.intern(Interner)
                     }),
+                _ => {
+                    never!("Only tuple has tuple field");
+                    return TyKind::Error.intern(Interner);
+                }
+            },
+            ProjectionElem::ClosureField(f) => match &base.kind(Interner) {
                 TyKind::Closure(id, subst) => closure_field(*id, subst, *f),
                 _ => {
-                    never!("Only tuple or closure has tuple or closure field");
+                    never!("Only closure has closure field");
                     return TyKind::Error.intern(Interner);
                 }
             },

crates/hir-ty/src/mir/borrowck.rs

@@ -205,7 +205,7 @@ fn place_case(db: &dyn HirDatabase, body: &MirBody, lvalue: &Place) -> Projectio
             | ProjectionElem::ConstantIndex { .. }
             | ProjectionElem::Subslice { .. }
             | ProjectionElem::Field(_)
-            | ProjectionElem::TupleOrClosureField(_)
+            | ProjectionElem::ClosureField(_)
             | ProjectionElem::Index(_) => {
                 is_part_of = true;
             }