Move lifetimes in front of type and const params but after self

crates/hir-def/src/generics.rs

@@ -249,13 +249,62 @@ impl GenericParams {
         self.lifetimes.iter()
     }
 
+    pub fn find_type_by_name(&self, name: &Name, parent: GenericDefId) -> Option<TypeParamId> {
+        self.type_or_consts.iter().find_map(|(id, p)| {
+            if p.name().as_ref() == Some(&name) && p.type_param().is_some() {
+                Some(TypeParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
+            } else {
+                None
+            }
+        })
+    }
+
+    pub fn find_const_by_name(&self, name: &Name, parent: GenericDefId) -> Option<ConstParamId> {
+        self.type_or_consts.iter().find_map(|(id, p)| {
+            if p.name().as_ref() == Some(&name) && p.const_param().is_some() {
+                Some(ConstParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
+            } else {
+                None
+            }
+        })
+    }
+
+    #[inline]
+    pub fn trait_self_param(&self) -> Option<LocalTypeOrConstParamId> {
+        if self.type_or_consts.is_empty() {
+            return None;
+        }
+        matches!(
+            self.type_or_consts[SELF_PARAM_ID_IN_SELF],
+            TypeOrConstParamData::TypeParamData(TypeParamData {
+                provenance: TypeParamProvenance::TraitSelf,
+                ..
+            })
+        )
+        .then(|| SELF_PARAM_ID_IN_SELF)
+    }
+
+    pub fn find_lifetime_by_name(
+        &self,
+        name: &Name,
+        parent: GenericDefId,
+    ) -> Option<LifetimeParamId> {
+        self.lifetimes.iter().find_map(|(id, p)| {
+            if &p.name == name {
+                Some(LifetimeParamId { local_id: id, parent })
+            } else {
+                None
+            }
+        })
+    }
+
     pub(crate) fn generic_params_query(
         db: &dyn DefDatabase,
         def: GenericDefId,
     ) -> Interned<GenericParams> {
         let _p = tracing::info_span!("generic_params_query").entered();
 
-        let krate = def.module(db).krate;
+        let krate = def.krate(db);
         let cfg_options = db.crate_graph();
         let cfg_options = &cfg_options[krate].cfg_options;
 
@@ -368,54 +417,6 @@ impl GenericParams {
             }),
         }
     }
-
-    pub fn find_type_by_name(&self, name: &Name, parent: GenericDefId) -> Option<TypeParamId> {
-        self.type_or_consts.iter().find_map(|(id, p)| {
-            if p.name().as_ref() == Some(&name) && p.type_param().is_some() {
-                Some(TypeParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
-            } else {
-                None
-            }
-        })
-    }
-
-    pub fn find_const_by_name(&self, name: &Name, parent: GenericDefId) -> Option<ConstParamId> {
-        self.type_or_consts.iter().find_map(|(id, p)| {
-            if p.name().as_ref() == Some(&name) && p.const_param().is_some() {
-                Some(ConstParamId::from_unchecked(TypeOrConstParamId { local_id: id, parent }))
-            } else {
-                None
-            }
-        })
-    }
-
-    pub fn trait_self_param(&self) -> Option<LocalTypeOrConstParamId> {
-        if self.type_or_consts.is_empty() {
-            return None;
-        }
-        matches!(
-            self.type_or_consts[SELF_PARAM_ID_IN_SELF],
-            TypeOrConstParamData::TypeParamData(TypeParamData {
-                provenance: TypeParamProvenance::TraitSelf,
-                ..
-            })
-        )
-        .then(|| SELF_PARAM_ID_IN_SELF)
-    }
-
-    pub fn find_lifetime_by_name(
-        &self,
-        name: &Name,
-        parent: GenericDefId,
-    ) -> Option<LifetimeParamId> {
-        self.lifetimes.iter().find_map(|(id, p)| {
-            if &p.name == name {
-                Some(LifetimeParamId { local_id: id, parent })
-            } else {
-                None
-            }
-        })
-    }
 }
 
 #[derive(Clone, Default)]

crates/hir-ty/src/generics.rs

@@ -2,8 +2,8 @@
 //!
 //! The layout for generics as expected by chalk are as follows:
 //! - Optional Self parameter
-//! - Type or Const parameters
 //! - Lifetime parameters
+//! - Type or Const parameters
 //! - Parent parameters
 //!
 //! where parent follows the same scheme.
@@ -20,19 +20,23 @@ use hir_def::{
     LocalLifetimeParamId, LocalTypeOrConstParamId, Lookup, TypeOrConstParamId, TypeParamId,
 };
 use intern::Interned;
+use itertools::chain;
 use stdx::TupleExt;
 
 use crate::{db::HirDatabase, lt_to_placeholder_idx, to_placeholder_idx, Interner, Substitution};
 
 pub(crate) fn generics(db: &dyn DefDatabase, def: GenericDefId) -> Generics {
     let parent_generics = parent_generic_def(db, def).map(|def| Box::new(generics(db, def)));
-    Generics { def, params: db.generic_params(def), parent_generics }
+    let params = db.generic_params(def);
+    let has_trait_self_param = params.trait_self_param().is_some();
+    Generics { def, params, parent_generics, has_trait_self_param }
 }
 #[derive(Clone, Debug)]
 pub(crate) struct Generics {
     def: GenericDefId,
     params: Interned<GenericParams>,
     parent_generics: Option<Box<Generics>>,
+    has_trait_self_param: bool,
 }
 
 impl<T> ops::Index<T> for Generics
@@ -74,10 +78,6 @@ impl Generics {
         self.params.iter_type_or_consts().map(from_toc_id(self)).map(TupleExt::head)
     }
 
-    pub(crate) fn iter_self_lt_id(&self) -> impl DoubleEndedIterator<Item = GenericParamId> + '_ {
-        self.params.iter_lt().map(from_lt_id(self)).map(TupleExt::head)
-    }
-
     /// Iterate over the params followed by the parent params.
     pub(crate) fn iter(
         &self,
@@ -89,19 +89,19 @@ impl Generics {
     pub(crate) fn iter_self(
         &self,
     ) -> impl DoubleEndedIterator<Item = (GenericParamId, GenericParamDataRef<'_>)> + '_ {
-        self.params
-            .iter_type_or_consts()
-            .map(from_toc_id(self))
-            .chain(self.params.iter_lt().map(from_lt_id(self)))
+        let mut toc = self.params.iter_type_or_consts().map(from_toc_id(self));
+        let trait_self_param = self.has_trait_self_param.then(|| toc.next()).flatten();
+        chain!(trait_self_param, self.params.iter_lt().map(from_lt_id(self)), toc)
     }
 
     /// Iterator over types and const params of parent.
     fn iter_parent(
         &self,
     ) -> impl DoubleEndedIterator<Item = (GenericParamId, GenericParamDataRef<'_>)> + '_ {
         self.parent_generics().into_iter().flat_map(|it| {
-            let lt_iter = it.params.iter_lt().map(from_lt_id(it));
-            it.params.iter_type_or_consts().map(from_toc_id(it)).chain(lt_iter)
+            let mut toc = it.params.iter_type_or_consts().map(from_toc_id(it));
+            let trait_self_param = it.has_trait_self_param.then(|| toc.next()).flatten();
+            chain!(trait_self_param, it.params.iter_lt().map(from_lt_id(it)), toc)
         })
     }
 
@@ -146,7 +146,10 @@ impl Generics {
         if param.parent == self.def {
             let idx = param.local_id.into_raw().into_u32() as usize;
             debug_assert!(idx <= self.params.len_type_or_consts());
-            Some(idx)
+            if self.params.trait_self_param() == Some(param.local_id) {
+                return Some(idx);
+            }
+            Some(self.params.len_lifetimes() + idx)
         } else {
             debug_assert_eq!(self.parent_generics().map(|it| it.def), Some(param.parent));
             self.parent_generics()
@@ -164,7 +167,7 @@ impl Generics {
         if lifetime.parent == self.def {
             let idx = lifetime.local_id.into_raw().into_u32() as usize;
             debug_assert!(idx <= self.params.len_lifetimes());
-            Some(self.params.len_type_or_consts() + idx)
+            Some(self.params.trait_self_param().is_some() as usize + idx)
         } else {
             debug_assert_eq!(self.parent_generics().map(|it| it.def), Some(lifetime.parent));
             self.parent_generics()