Auto merge of #17417 - Wilfred:intern_macros_salsa, r=Veykril

refactor: Prefer plain trait definitions over macros for impl_intern_value_trivial

`impl_intern_value_trivial` can be defined with a trait directly, so prefer that over a macro definition.
diff --git a/crates/hir-def/src/lib.rs b/crates/hir-def/src/lib.rs
index b1f97f2..0dcd912 100644
--- a/crates/hir-def/src/lib.rs
+++ b/crates/hir-def/src/lib.rs
@@ -73,7 +73,7 @@
 
 use base_db::{
     impl_intern_key,
-    salsa::{self, impl_intern_value_trivial},
+    salsa::{self, InternValueTrivial},
     CrateId,
 };
 use hir_expand::{
@@ -187,7 +187,7 @@
 macro_rules! impl_intern {
     ($id:ident, $loc:ident, $intern:ident, $lookup:ident) => {
         impl_intern_key!($id);
-        impl_intern_value_trivial!($loc);
+        impl InternValueTrivial for $loc {}
         impl_intern_lookup!(DefDatabase, $id, $loc, $intern, $lookup);
     };
 }
@@ -535,7 +535,7 @@
     pub parent: GenericDefId,
     pub local_id: LocalTypeOrConstParamId,
 }
-impl_intern_value_trivial!(TypeOrConstParamId);
+impl InternValueTrivial for TypeOrConstParamId {}
 
 /// A TypeOrConstParamId with an invariant that it actually belongs to a type
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -597,7 +597,7 @@
     pub local_id: LocalLifetimeParamId,
 }
 pub type LocalLifetimeParamId = Idx<generics::LifetimeParamData>;
-impl_intern_value_trivial!(LifetimeParamId);
+impl InternValueTrivial for LifetimeParamId {}
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum ItemContainerId {
diff --git a/crates/hir-expand/src/lib.rs b/crates/hir-expand/src/lib.rs
index 8859b47..ec0716c 100644
--- a/crates/hir-expand/src/lib.rs
+++ b/crates/hir-expand/src/lib.rs
@@ -31,7 +31,7 @@
 
 use std::{fmt, hash::Hash};
 
-use base_db::{salsa::impl_intern_value_trivial, CrateId, FileId};
+use base_db::{salsa::InternValueTrivial, CrateId, FileId};
 use either::Either;
 use span::{
     Edition, ErasedFileAstId, FileAstId, FileRange, HirFileIdRepr, Span, SpanAnchor,
@@ -173,7 +173,7 @@
     pub kind: MacroCallKind,
     pub ctxt: SyntaxContextId,
 }
-impl_intern_value_trivial!(MacroCallLoc);
+impl InternValueTrivial for MacroCallLoc {}
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct MacroDefId {
diff --git a/crates/hir-ty/src/db.rs b/crates/hir-ty/src/db.rs
index 90bf46b..000871e 100644
--- a/crates/hir-ty/src/db.rs
+++ b/crates/hir-ty/src/db.rs
@@ -5,7 +5,7 @@
 
 use base_db::{
     impl_intern_key,
-    salsa::{self, impl_intern_value_trivial},
+    salsa::{self, InternValueTrivial},
     CrateId, Upcast,
 };
 use hir_def::{
@@ -298,7 +298,8 @@
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct InternedClosure(pub DefWithBodyId, pub ExprId);
-impl_intern_value_trivial!(InternedClosure);
+
+impl InternValueTrivial for InternedClosure {}
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct InternedCoroutineId(salsa::InternId);
@@ -306,7 +307,7 @@
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct InternedCoroutine(pub DefWithBodyId, pub ExprId);
-impl_intern_value_trivial!(InternedCoroutine);
+impl InternValueTrivial for InternedCoroutine {}
 
 /// This exists just for Chalk, because Chalk just has a single `FnDefId` where
 /// we have different IDs for struct and enum variant constructors.
diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs
index 26a839f..9d596e9 100644
--- a/crates/hir-ty/src/lib.rs
+++ b/crates/hir-ty/src/lib.rs
@@ -52,7 +52,7 @@
     hash::{BuildHasherDefault, Hash},
 };
 
-use base_db::salsa::impl_intern_value_trivial;
+use base_db::salsa::InternValueTrivial;
 use chalk_ir::{
     fold::{Shift, TypeFoldable},
     interner::HasInterner,
@@ -606,7 +606,7 @@
     AssociatedTypeImplTrait(hir_def::TypeAliasId, ImplTraitIdx),
     AsyncBlockTypeImplTrait(hir_def::DefWithBodyId, ExprId),
 }
-impl_intern_value_trivial!(ImplTraitId);
+impl InternValueTrivial for ImplTraitId {}
 
 #[derive(PartialEq, Eq, Debug, Hash)]
 pub struct ImplTraits {
diff --git a/crates/hir-ty/src/lower.rs b/crates/hir-ty/src/lower.rs
index d3e7954..2e100d5 100644
--- a/crates/hir-ty/src/lower.rs
+++ b/crates/hir-ty/src/lower.rs
@@ -11,7 +11,7 @@
 };
 
 use base_db::{
-    salsa::{impl_intern_value_trivial, Cycle},
+    salsa::{Cycle, InternValueTrivial},
     CrateId,
 };
 use chalk_ir::{
@@ -1965,7 +1965,9 @@
     StructId(StructId),
     EnumVariantId(EnumVariantId),
 }
-impl_intern_value_trivial!(CallableDefId);
+
+impl InternValueTrivial for CallableDefId {}
+
 impl_from!(FunctionId, StructId, EnumVariantId for CallableDefId);
 impl From<CallableDefId> for ModuleDefId {
     fn from(def: CallableDefId) -> ModuleDefId {
diff --git a/crates/salsa/src/interned.rs b/crates/salsa/src/interned.rs
index bfa9cc0..eef8bcc 100644
--- a/crates/salsa/src/interned.rs
+++ b/crates/salsa/src/interned.rs
@@ -98,26 +98,27 @@
     }
 }
 
-/// Implement [`InternValue`] trivially, that is without actually mapping at all.
-#[macro_export]
-macro_rules! impl_intern_value_trivial {
-    ($($ty:ty),*) => {
-        $(
-            impl $crate::InternValue for $ty {
-                type Key = $ty;
-                #[inline]
-                fn into_key(&self) -> Self::Key {
-                    self.clone()
-                }
-                #[inline]
-                fn with_key<F: FnOnce(&Self::Key) -> T, T>(&self, f: F) -> T {
-                    f(self)
-                }
-            }
-        )*
-    };
+pub trait InternValueTrivial
+where
+    Self: Eq + Hash + Debug + Clone,
+{
 }
-impl_intern_value_trivial!(String);
+
+/// Implement [`InternValue`] trivially, that is without actually mapping at all.
+impl<V: InternValueTrivial> InternValue for V {
+    type Key = Self;
+    #[inline]
+    fn into_key(&self) -> Self::Key {
+        self.clone()
+    }
+    #[inline]
+    fn with_key<F: FnOnce(&Self::Key) -> T, T>(&self, f: F) -> T {
+        f(self)
+    }
+}
+
+impl InternValueTrivial for String {}
+
 #[derive(Debug)]
 struct Slot<V> {
     /// DatabaseKeyIndex for this slot.
diff --git a/crates/salsa/src/lib.rs b/crates/salsa/src/lib.rs
index 4292054..e11e6e2 100644
--- a/crates/salsa/src/lib.rs
+++ b/crates/salsa/src/lib.rs
@@ -40,7 +40,7 @@
 
 pub use crate::durability::Durability;
 pub use crate::intern_id::InternId;
-pub use crate::interned::{InternKey, InternValue};
+pub use crate::interned::{InternKey, InternValue, InternValueTrivial};
 pub use crate::runtime::Runtime;
 pub use crate::runtime::RuntimeId;
 pub use crate::storage::Storage;