Do not use dyn HirDatabase, only dyn SourceDatabase

crates/base-db/src/lib.rs

@@ -310,6 +310,8 @@ pub trait SourceDatabase: salsa::Database + std::fmt::Debug {
     fn nonce_and_revision(&self) -> (Nonce, salsa::Revision);
 
     fn line_column(&self, file: FileId, offset: TextSize) -> Result<(u32, u32), ()>;
+
+    fn as_dyn(&self) -> &dyn SourceDatabase;
 }
 
 static NEXT_NONCE: AtomicUsize = AtomicUsize::new(0);

crates/hir-def/src/test_db.rs

@@ -145,6 +145,10 @@ impl SourceDatabase for TestDB {
     fn line_column(&self, _file: FileId, _offset: syntax::TextSize) -> Result<(u32, u32), ()> {
         Err(())
     }
+
+    fn as_dyn(&self) -> &dyn SourceDatabase {
+        self
+    }
 }
 
 impl TestDB {

crates/hir-ty/src/autoderef.rs

@@ -7,13 +7,13 @@
 
 use std::fmt;
 
+use base_db::SourceDatabase;
 use hir_def::{TraitId, TypeAliasId};
 use rustc_type_ir::inherent::{IntoKind, Ty as _};
 use tracing::debug;
 
 use crate::{
     ParamEnvAndCrate, Span,
-    db::HirDatabase,
     infer::InferenceContext,
     next_solver::{
         Canonical, DbInterner, ParamEnv, TraitRef, Ty, TyKind, TypingMode,
@@ -35,7 +35,7 @@ const AUTODEREF_RECURSION_LIMIT: usize = 20;
 /// - a type won't be yielded more than once; in other words, the returned iterator will stop if it
 ///   detects a cycle in the deref chain.
 pub fn autoderef<'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     env: ParamEnvAndCrate<'db>,
     ty: Canonical<'db, Ty<'db>>,
 ) -> impl Iterator<Item = Ty<'db>> + use<'db> {

crates/hir-ty/src/builtin_derive.rs

@@ -2,6 +2,7 @@
 
 use std::ops::ControlFlow;
 
+use base_db::SourceDatabase;
 use hir_def::{
     AdtId, BuiltinDeriveImplId, BuiltinDeriveImplLoc, HasModule, LocalFieldId, TraitId,
     TypeOrConstParamId, TypeParamId,
@@ -82,7 +83,7 @@ pub(crate) fn generics_of<'db>(
     }
 }
 
-pub fn generic_params_count(db: &dyn HirDatabase, id: BuiltinDeriveImplId) -> usize {
+pub fn generic_params_count(db: &dyn SourceDatabase, id: BuiltinDeriveImplId) -> usize {
     let loc = id.loc(db);
     let adt_params = GenericParams::of(db, loc.adt.into());
     let extra_params_count = match loc.trait_ {
@@ -154,7 +155,7 @@ pub fn impl_trait<'db>(
 }
 
 #[salsa::tracked(returns(ref))]
-pub fn predicates(db: &dyn HirDatabase, impl_: BuiltinDeriveImplId) -> GenericPredicates {
+pub fn predicates(db: &dyn SourceDatabase, impl_: BuiltinDeriveImplId) -> GenericPredicates {
     let loc = impl_.loc(db);
     let generic_params = GenericParams::of(db, loc.adt.into());
     let interner = DbInterner::new_with(db, loc.module(db).krate(db));

crates/hir-ty/src/consteval.rs

@@ -3,7 +3,7 @@
 #[cfg(test)]
 mod tests;
 
-use base_db::Crate;
+use base_db::{Crate, SourceDatabase};
 use hir_def::{
     ConstId, EnumVariantId, ExpressionStoreOwnerId, HasModule, StaticId,
     attrs::AttrFlags,
@@ -46,7 +46,7 @@ impl ConstEvalError<'_> {
     pub fn pretty_print(
         &self,
         f: &mut String,
-        db: &dyn HirDatabase,
+        db: &dyn SourceDatabase,
         span_formatter: impl Fn(span::FileId, span::TextRange) -> String,
         display_target: DisplayTarget,
     ) -> std::result::Result<(), std::fmt::Error> {
@@ -214,7 +214,11 @@ pub(crate) fn literal_ty<'db>(
 }
 
 /// Interns a possibly-unknown target usize
-pub fn usize_const<'db>(db: &'db dyn HirDatabase, value: Option<u128>, krate: Crate) -> Const<'db> {
+pub fn usize_const<'db>(
+    db: &'db dyn SourceDatabase,
+    value: Option<u128>,
+    krate: Crate,
+) -> Const<'db> {
     let interner = DbInterner::new_no_crate(db);
     let value = match value {
         Some(value) => value,
@@ -236,7 +240,7 @@ pub fn allocation_as_usize(ec: Allocation<'_>) -> u128 {
     u128::from_le_bytes(pad16(&ec.memory, false))
 }
 
-pub fn try_const_usize<'db>(db: &'db dyn HirDatabase, c: Const<'db>) -> Option<u128> {
+pub fn try_const_usize<'db>(db: &'db dyn SourceDatabase, c: Const<'db>) -> Option<u128> {
     match c.kind() {
         ConstKind::Param(_) => None,
         ConstKind::Infer(_) => None,
@@ -274,7 +278,7 @@ pub fn allocation_as_isize(ec: Allocation<'_>) -> i128 {
     i128::from_le_bytes(pad16(&ec.memory, true))
 }
 
-pub fn try_const_isize<'db>(db: &'db dyn HirDatabase, c: Const<'db>) -> Option<i128> {
+pub fn try_const_isize<'db>(db: &'db dyn SourceDatabase, c: Const<'db>) -> Option<i128> {
     match c.kind() {
         ConstKind::Param(_) => None,
         ConstKind::Infer(_) => None,
@@ -323,7 +327,7 @@ pub(crate) enum CreateConstError<'db> {
 }
 
 pub(crate) fn path_to_const<'a, 'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     resolver: &Resolver<'db>,
     generics: &dyn Fn() -> &'a Generics<'db>,
     forbid_params_after: Option<u32>,
@@ -416,7 +420,7 @@ pub(crate) fn create_anon_const<'a, 'db>(
 
 #[salsa::tracked(cycle_result = const_eval_discriminant_cycle_result)]
 pub(crate) fn const_eval_discriminant_variant<'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     variant_id: EnumVariantId,
 ) -> Result<i128, ConstEvalError<'db>> {
     let interner = DbInterner::new_no_crate(db);
@@ -452,15 +456,15 @@ pub(crate) fn const_eval_discriminant_variant<'db>(
 }
 
 fn const_eval_discriminant_cycle_result<'db>(
-    _: &'db dyn HirDatabase,
+    _: &'db dyn SourceDatabase,
     _: salsa::Id,
     _: EnumVariantId,
 ) -> Result<i128, ConstEvalError<'db>> {
     Err(ConstEvalError::MirLowerError(MirLowerError::Loop))
 }
 
 pub(crate) fn const_eval<'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     def: ConstId,
     subst: GenericArgs<'db>,
     trait_env: Option<ParamEnvAndCrate<'db>>,
@@ -472,7 +476,7 @@ pub(crate) fn const_eval<'db>(
 
     #[salsa::tracked(returns(ref), cycle_result = const_eval_cycle_result)]
     pub(crate) fn const_eval_query<'db>(
-        db: &'db dyn HirDatabase,
+        db: &'db dyn SourceDatabase,
         def: ConstId,
         subst: StoredGenericArgs,
         trait_env: Option<StoredParamEnvAndCrate>,
@@ -488,7 +492,7 @@ pub(crate) fn const_eval<'db>(
     }
 
     pub(crate) fn const_eval_cycle_result<'db>(
-        _: &'db dyn HirDatabase,
+        _: &'db dyn SourceDatabase,
         _: salsa::Id,
         _: ConstId,
         _: StoredGenericArgs,
@@ -499,7 +503,7 @@ pub(crate) fn const_eval<'db>(
 }
 
 pub(crate) fn anon_const_eval<'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     def: AnonConstId<'db>,
     subst: GenericArgs<'db>,
     trait_env: Option<ParamEnvAndCrate<'db>>,
@@ -511,7 +515,7 @@ pub(crate) fn anon_const_eval<'db>(
 
     #[salsa::tracked(returns(ref), cycle_result = anon_const_eval_cycle_result)]
     pub(crate) fn anon_const_eval_query<'db>(
-        db: &'db dyn HirDatabase,
+        db: &'db dyn SourceDatabase,
         def: AnonConstId<'db>,
         subst: StoredGenericArgs,
         trait_env: Option<StoredParamEnvAndCrate>,
@@ -530,7 +534,7 @@ pub(crate) fn anon_const_eval<'db>(
     }
 
     pub(crate) fn anon_const_eval_cycle_result<'db>(
-        _: &'db dyn HirDatabase,
+        _: &'db dyn SourceDatabase,
         _: salsa::Id,
         _: AnonConstId<'db>,
         _: StoredGenericArgs,
@@ -541,7 +545,7 @@ pub(crate) fn anon_const_eval<'db>(
 }
 
 pub(crate) fn const_eval_static<'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     def: StaticId,
 ) -> Result<Allocation<'db>, ConstEvalError<'db>> {
     return match const_eval_static_query(db, def) {
@@ -551,7 +555,7 @@ pub(crate) fn const_eval_static<'db>(
 
     #[salsa::tracked(returns(ref), cycle_result = const_eval_static_cycle_result)]
     pub(crate) fn const_eval_static_query<'db>(
-        db: &'db dyn HirDatabase,
+        db: &'db dyn SourceDatabase,
         def: StaticId,
     ) -> Result<StoredAllocation, ConstEvalError<'db>> {
         let interner = DbInterner::new_no_crate(db);
@@ -566,7 +570,7 @@ pub(crate) fn const_eval_static<'db>(
     }
 
     pub(crate) fn const_eval_static_cycle_result<'db>(
-        _: &'db dyn HirDatabase,
+        _: &'db dyn SourceDatabase,
         _: salsa::Id,
         _: StaticId,
     ) -> Result<StoredAllocation, ConstEvalError<'db>> {

crates/hir-ty/src/db.rs

@@ -37,14 +37,7 @@ use crate::{
     traits::{ParamEnvAndCrate, StoredParamEnvAndCrate},
 };
 
-#[salsa::db]
 pub trait HirDatabase: SourceDatabase + 'static {
-    /// Manual implementation of upcasting from `dyn SourceDatabase` to `dyn HirDatabase`.
-    ///
-    /// This function is needed because Rust can't perform this upcasting automatically
-    /// in the general case, as `Self` could be unsized.
-    fn as_dyn(&self) -> &dyn HirDatabase;
-
     // region:mir
 
     // FIXME: Collapse `mir_body_for_closure` into `mir_body`
@@ -334,17 +327,7 @@ pub trait HirDatabase: SourceDatabase + 'static {
     }
 }
 
-#[salsa::db]
-impl<T: SourceDatabase> HirDatabase for T {
-    fn as_dyn(&self) -> &dyn HirDatabase {
-        self
-    }
-}
-
-#[test]
-fn hir_database_is_dyn_compatible() {
-    fn _assert_dyn_compatible(_: &dyn HirDatabase) {}
-}
+impl<T: SourceDatabase + ?Sized> HirDatabase for T {}
 
 #[salsa::interned(debug, revisions = usize::MAX)]
 #[derive(PartialOrd, Ord)]
@@ -367,7 +350,7 @@ pub struct InternedClosureId<'db> {
 
 impl<'db> InternedClosureId<'db> {
     #[inline]
-    pub fn new(db: &'db dyn HirDatabase, loc: InternedClosure<'db>) -> Self {
+    pub fn new(db: &'db dyn SourceDatabase, loc: InternedClosure<'db>) -> Self {
         if cfg!(debug_assertions) {
             let store = ExpressionStore::of(db, loc.owner.expression_store_owner(db));
             let expr = &store[loc.expr];
@@ -395,7 +378,7 @@ pub struct InternedCoroutineId<'db> {
 
 impl<'db> InternedCoroutineId<'db> {
     #[inline]
-    pub fn new(db: &'db dyn HirDatabase, loc: InternedClosure<'db>) -> Self {
+    pub fn new(db: &'db dyn SourceDatabase, loc: InternedClosure<'db>) -> Self {
         if cfg!(debug_assertions) {
             let store = ExpressionStore::of(db, loc.owner.expression_store_owner(db));
             let expr = &store[loc.expr];
@@ -424,7 +407,7 @@ pub struct InternedCoroutineClosureId<'db> {
 
 impl<'db> InternedCoroutineClosureId<'db> {
     #[inline]
-    pub fn new(db: &'db dyn HirDatabase, loc: InternedClosure<'db>) -> Self {
+    pub fn new(db: &'db dyn SourceDatabase, loc: InternedClosure<'db>) -> Self {
         if cfg!(debug_assertions) {
             let store = ExpressionStore::of(db, loc.owner.expression_store_owner(db));
             let expr = &store[loc.expr];
@@ -492,7 +475,7 @@ impl HasResolver for AnonConstId<'_> {
 
 impl<'db> AnonConstId<'db> {
     pub fn all_from_signature(
-        db: &'db dyn HirDatabase,
+        db: &'db dyn SourceDatabase,
         def: GenericDefId,
     ) -> ArrayVec<&'db [Self], 5> {
         let mut result = ArrayVec::new();
@@ -540,7 +523,7 @@ pub enum GeneralConstId<'db> {
 impl_from!(impl<'db> ConstId, StaticId, AnonConstId<'db> for GeneralConstId<'db>);
 
 impl<'db> GeneralConstId<'db> {
-    pub fn generic_def(self, db: &'db dyn HirDatabase) -> Option<GenericDefId> {
+    pub fn generic_def(self, db: &'db dyn SourceDatabase) -> Option<GenericDefId> {
         match self {
             GeneralConstId::ConstId(it) => Some(it.into()),
             GeneralConstId::StaticId(it) => Some(it.into()),

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

@@ -15,6 +15,7 @@ mod case_conv;
 
 use std::fmt;
 
+use base_db::SourceDatabase;
 use hir_def::{
     AdtId, ConstId, EnumId, EnumVariantId, FunctionId, HasModule, ItemContainerId, Lookup,
     ModuleDefId, ModuleId, StaticId, StructId, TraitId, TypeAliasId, UnionId,
@@ -44,7 +45,7 @@ use crate::db::HirDatabase;
 
 use self::case_conv::{to_camel_case, to_lower_snake_case, to_upper_snake_case};
 
-pub fn incorrect_case(db: &dyn HirDatabase, owner: ModuleDefId) -> Vec<IncorrectCase> {
+pub fn incorrect_case(db: &dyn SourceDatabase, owner: ModuleDefId) -> Vec<IncorrectCase> {
     let _p = tracing::info_span!("incorrect_case").entered();
     let mut validator = DeclValidator::new(db);
     validator.validate_item(owner);
@@ -123,7 +124,7 @@ pub struct IncorrectCase {
 }
 
 pub(super) struct DeclValidator<'a> {
-    db: &'a dyn HirDatabase,
+    db: &'a dyn SourceDatabase,
     pub(super) sink: Vec<IncorrectCase>,
 }
 
@@ -135,7 +136,7 @@ struct Replacement {
 }
 
 impl<'a> DeclValidator<'a> {
-    pub(super) fn new(db: &'a dyn HirDatabase) -> DeclValidator<'a> {
+    pub(super) fn new(db: &'a dyn SourceDatabase) -> DeclValidator<'a> {
         DeclValidator { db, sink: Vec::new() }
     }
 

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

@@ -4,7 +4,7 @@
 
 use std::fmt;
 
-use base_db::Crate;
+use base_db::{Crate, SourceDatabase};
 use either::Either;
 use hir_def::{
     AdtId, AssocItemId, CallableDefId, DefWithBodyId, HasModule, ItemContainerId, Lookup,
@@ -76,7 +76,7 @@ pub enum BodyValidationDiagnostic<'db> {
 
 impl<'db> BodyValidationDiagnostic<'db> {
     pub fn collect(
-        db: &'db dyn HirDatabase,
+        db: &'db dyn SourceDatabase,
         owner: DefWithBodyId,
         validate_lints: bool,
     ) -> Vec<BodyValidationDiagnostic<'db>> {
@@ -113,7 +113,7 @@ struct ExprValidator<'db> {
 
 impl<'db> ExprValidator<'db> {
     #[inline]
-    fn db(&self) -> &'db dyn HirDatabase {
+    fn db(&self) -> &'db dyn SourceDatabase {
         self.infcx.interner.db
     }
 
@@ -566,7 +566,7 @@ struct FilterMapNextChecker<'db> {
 }
 
 impl<'db> FilterMapNextChecker<'db> {
-    fn new(lang_items: &'db LangItems, db: &'db dyn HirDatabase) -> Self {
+    fn new(lang_items: &'db LangItems, db: &'db dyn SourceDatabase) -> Self {
         // Find and store the FunctionIds for Iterator::filter_map and Iterator::next
         let (next_function_id, filter_map_function_id) = match lang_items.IteratorNext {
             Some(next_function_id) => (
@@ -622,7 +622,7 @@ impl<'db> FilterMapNextChecker<'db> {
 }
 
 pub fn record_literal_missing_fields<'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     infer: &InferenceResult<'db>,
     id: ExprId,
     expr: &Expr,
@@ -665,7 +665,7 @@ pub fn record_literal_missing_fields<'db>(
 }
 
 pub fn record_pattern_missing_fields<'db>(
-    db: &'db dyn HirDatabase,
+    db: &'db dyn SourceDatabase,
     infer: &InferenceResult<'db>,
     id: PatId,
     pat: &Pat,