Auto merge of #17474 - Veykril:ty-perf-stuff, r=Veykril

internal: Remove some allocations from hir-ty

Author: bors

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

@@ -604,7 +604,6 @@ pub(crate) fn associated_ty_data_query(
     // Lower bounds -- we could/should maybe move this to a separate query in `lower`
     let type_alias_data = db.type_alias_data(type_alias);
     let generic_params = generics(db.upcast(), type_alias.into());
-    // let bound_vars = generic_params.bound_vars_subst(DebruijnIndex::INNERMOST);
     let resolver = hir_def::resolver::HasResolver::resolver(type_alias, db.upcast());
     let ctx = crate::TyLoweringContext::new(db, &resolver, type_alias.into())
         .with_type_param_mode(crate::lower::ParamLoweringMode::Variable);

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

@@ -21,11 +21,12 @@ use crate::{
     chalk_db,
     consteval::ConstEvalError,
     layout::{Layout, LayoutError},
+    lower::{GenericDefaults, GenericPredicates},
     method_resolution::{InherentImpls, TraitImpls, TyFingerprint},
     mir::{BorrowckResult, MirBody, MirLowerError},
-    Binders, CallableDefId, ClosureId, Const, FnDefId, GenericArg, ImplTraitId, ImplTraits,
-    InferenceResult, Interner, PolyFnSig, QuantifiedWhereClause, Substitution, TraitEnvironment,
-    TraitRef, Ty, TyDefId, ValueTyDefId,
+    Binders, CallableDefId, ClosureId, Const, FnDefId, ImplTraitId, ImplTraits, InferenceResult,
+    Interner, PolyFnSig, QuantifiedWhereClause, Substitution, TraitEnvironment, TraitRef, Ty,
+    TyDefId, ValueTyDefId,
 };
 use hir_expand::name::Name;
 
@@ -147,7 +148,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     ) -> Arc<[Binders<QuantifiedWhereClause>]>;
 
     #[salsa::invoke(crate::lower::generic_predicates_query)]
-    fn generic_predicates(&self, def: GenericDefId) -> Arc<[Binders<QuantifiedWhereClause>]>;
+    fn generic_predicates(&self, def: GenericDefId) -> GenericPredicates;
 
     #[salsa::invoke(crate::lower::trait_environment_for_body_query)]
     #[salsa::transparent]
@@ -158,7 +159,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
 
     #[salsa::invoke(crate::lower::generic_defaults_query)]
     #[salsa::cycle(crate::lower::generic_defaults_recover)]
-    fn generic_defaults(&self, def: GenericDefId) -> Arc<[Binders<GenericArg>]>;
+    fn generic_defaults(&self, def: GenericDefId) -> GenericDefaults;
 
     #[salsa::invoke(InherentImpls::inherent_impls_in_crate_query)]
     fn inherent_impls_in_crate(&self, krate: CrateId) -> Arc<InherentImpls>;

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

@@ -64,8 +64,8 @@ use crate::{
     traits::FnTrait,
     utils::{InTypeConstIdMetadata, UnevaluatedConstEvaluatorFolder},
     AliasEq, AliasTy, Binders, ClosureId, Const, DomainGoal, GenericArg, Goal, ImplTraitId,
-    ImplTraitIdx, InEnvironment, Interner, Lifetime, OpaqueTyId, ProjectionTy, Substitution,
-    TraitEnvironment, Ty, TyBuilder, TyExt,
+    ImplTraitIdx, InEnvironment, Interner, Lifetime, OpaqueTyId, ParamLoweringMode, ProjectionTy,
+    Substitution, TraitEnvironment, Ty, TyBuilder, TyExt,
 };
 
 // This lint has a false positive here. See the link below for details.
@@ -791,7 +791,8 @@ impl<'a> InferenceContext<'a> {
 
     fn collect_fn(&mut self, func: FunctionId) {
         let data = self.db.function_data(func);
-        let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver, func.into())
+        let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver, self.owner.into())
+            .with_type_param_mode(ParamLoweringMode::Placeholder)
             .with_impl_trait_mode(ImplTraitLoweringMode::Param);
         let mut param_tys =
             data.params.iter().map(|type_ref| ctx.lower_ty(type_ref)).collect::<Vec<_>>();
@@ -826,6 +827,7 @@ impl<'a> InferenceContext<'a> {
         let return_ty = &*data.ret_type;
 
         let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver, self.owner.into())
+            .with_type_param_mode(ParamLoweringMode::Placeholder)
             .with_impl_trait_mode(ImplTraitLoweringMode::Opaque);
         let return_ty = ctx.lower_ty(return_ty);
         let return_ty = self.insert_type_vars(return_ty);

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

@@ -330,18 +330,15 @@ pub(crate) fn make_single_type_binders<T: HasInterner<Interner = Interner>>(
     )
 }
 
-pub(crate) fn make_binders_with_count<T: HasInterner<Interner = Interner>>(
+pub(crate) fn make_binders<T: HasInterner<Interner = Interner>>(
     db: &dyn HirDatabase,
-    count: usize,
     generics: &Generics,
     value: T,
 ) -> Binders<T> {
-    let it = generics.iter_id().take(count);
-
     Binders::new(
         VariableKinds::from_iter(
             Interner,
-            it.map(|x| match x {
+            generics.iter_id().map(|x| match x {
                 hir_def::GenericParamId::ConstParamId(id) => {
                     chalk_ir::VariableKind::Const(db.const_param_ty(id))
                 }
@@ -355,14 +352,6 @@ pub(crate) fn make_binders_with_count<T: HasInterner<Interner = Interner>>(
     )
 }
 
-pub(crate) fn make_binders<T: HasInterner<Interner = Interner>>(
-    db: &dyn HirDatabase,
-    generics: &Generics,
-    value: T,
-) -> Binders<T> {
-    make_binders_with_count(db, usize::MAX, generics, value)
-}
-
 // FIXME: get rid of this, just replace it by FnPointer
 /// A function signature as seen by type inference: Several parameter types and
 /// one return type.
@@ -524,14 +513,16 @@ pub type PolyFnSig = Binders<CallableSig>;
 
 impl CallableSig {
     pub fn from_params_and_return(
-        mut params: Vec<Ty>,
+        params: impl ExactSizeIterator<Item = Ty>,
         ret: Ty,
         is_varargs: bool,
         safety: Safety,
         abi: FnAbi,
     ) -> CallableSig {
-        params.push(ret);
-        CallableSig { params_and_return: params.into(), is_varargs, safety, abi }
+        let mut params_and_return = Vec::with_capacity(params.len() + 1);
+        params_and_return.extend(params);
+        params_and_return.push(ret);
+        CallableSig { params_and_return: params_and_return.into(), is_varargs, safety, abi }
     }
 
     pub fn from_def(db: &dyn HirDatabase, def: FnDefId, substs: &Substitution) -> CallableSig {
@@ -946,8 +937,7 @@ pub fn callable_sig_from_fn_trait(
                     .as_tuple()?
                     .iter(Interner)
                     .map(|it| it.assert_ty_ref(Interner))
-                    .cloned()
-                    .collect();
+                    .cloned();
 
                 return Some((
                     fn_x,