4 files changed, 58 insertions, 17 deletions

diff --git a/crates/ra_hir/src/code_model_api.rs b/crates/ra_hir/src/code_model_api.rs
index b53fe1f63..28de9e76a 100644
--- a/crates/ra_hir/src/code_model_api.rs
+++ b/crates/ra_hir/src/code_model_api.rs
@@ -189,7 +189,7 @@ impl Module {
         }
     }
 
-    pub(crate) fn resolver(&self, db: &impl HirDatabase) -> Resolver {
+    pub(crate) fn resolver(&self, db: &impl DefDatabase) -> Resolver {
         let def_map = db.crate_def_map(self.krate);
         Resolver::default().push_module_scope(def_map, self.module_id)
     }
@@ -552,16 +552,21 @@ impl Function {
         db.trait_items_index(self.module(db)).get_parent_trait((*self).into())
     }
 
+    pub fn container(&self, db: &impl DefDatabase) -> Option<Container> {
+        if let Some(impl_block) = self.impl_block(db) {
+            Some(impl_block.into())
+        } else if let Some(trait_) = self.parent_trait(db) {
+            Some(trait_.into())
+        } else {
+            None
+        }
+    }
+
     // FIXME: move to a more general type for 'body-having' items
     /// Builds a resolver for code inside this item.
     pub(crate) fn resolver(&self, db: &impl HirDatabase) -> Resolver {
         // take the outer scope...
-        // FIXME abstract over containers (trait/impl)
-        let r = self
-            .impl_block(db)
-            .map(|ib| ib.resolver(db))
-            .or_else(|| self.parent_trait(db).map(|tr| tr.resolver(db)))
-            .unwrap_or_else(|| self.module(db).resolver(db));
+        let r = self.container(db).map_or_else(|| self.module(db).resolver(db), |c| c.resolver(db));
         // ...and add generic params, if present
         let p = self.generic_params(db);
         let r = if !p.params.is_empty() { r.push_generic_params_scope(p) } else { r };
@@ -707,7 +712,7 @@ impl Trait {
         db.trait_data(self)
     }
 
-    pub fn resolver(&self, db: &impl HirDatabase) -> Resolver {
+    pub(crate) fn resolver(&self, db: &impl DefDatabase) -> Resolver {
         let r = self.module(db).resolver(db);
         // add generic params, if present
         let p = self.generic_params(db);
@@ -746,6 +751,21 @@ impl TypeAlias {
         ImplBlock::containing(module_impls, (*self).into())
     }
 
+    /// The containing trait, if this is a trait method definition.
+    pub fn parent_trait(&self, db: &impl DefDatabase) -> Option<Trait> {
+        db.trait_items_index(self.module(db)).get_parent_trait((*self).into())
+    }
+
+    pub fn container(&self, db: &impl DefDatabase) -> Option<Container> {
+        if let Some(impl_block) = self.impl_block(db) {
+            Some(impl_block.into())
+        } else if let Some(trait_) = self.parent_trait(db) {
+            Some(trait_.into())
+        } else {
+            None
+        }
+    }
+
     pub fn type_ref(self, db: &impl DefDatabase) -> Arc<TypeRef> {
         db.type_alias_ref(self)
     }
@@ -769,3 +789,18 @@ impl Docs for TypeAlias {
         docs_from_ast(&*self.source(db).1)
     }
 }
+
+pub enum Container {
+    Trait(Trait),
+    ImplBlock(ImplBlock),
+}
+impl_froms!(Container: Trait, ImplBlock);
+
+impl Container {
+    pub(crate) fn resolver(&self, db: &impl DefDatabase) -> Resolver {
+        match self {
+            Container::Trait(trait_) => trait_.resolver(db),
+            Container::ImplBlock(impl_block) => impl_block.resolver(db),
+        }
+    }
+}
diff --git a/crates/ra_hir/src/generics.rs b/crates/ra_hir/src/generics.rs
index 51c846e91..f92b146ef 100644
--- a/crates/ra_hir/src/generics.rs
+++ b/crates/ra_hir/src/generics.rs
@@ -9,7 +9,7 @@ use ra_syntax::ast::{self, NameOwner, TypeParamsOwner};
 
 use crate::{
     db::DefDatabase,
-    Name, AsName, Function, Struct, Enum, Trait, TypeAlias, ImplBlock
+    Name, AsName, Function, Struct, Enum, Trait, TypeAlias, ImplBlock, Container
 };
 
 /// Data about a generic parameter (to a function, struct, impl, ...).
@@ -27,6 +27,7 @@ pub struct GenericParams {
     pub(crate) params: Vec<GenericParam>,
 }
 
+// FIXME: consts can have type parameters from their parents (i.e. associated consts of traits)
 #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
 pub enum GenericDef {
     Function(Function),
@@ -45,12 +46,8 @@ impl GenericParams {
     ) -> Arc<GenericParams> {
         let mut generics = GenericParams::default();
         let parent = match def {
-            // FIXME abstract over containers (trait/impl)
-            GenericDef::Function(it) => it
-                .impl_block(db)
-                .map(GenericDef::from)
-                .or_else(|| it.parent_trait(db).map(GenericDef::from)),
-            GenericDef::TypeAlias(it) => it.impl_block(db).map(GenericDef::from),
+            GenericDef::Function(it) => it.container(db).map(GenericDef::from),
+            GenericDef::TypeAlias(it) => it.container(db).map(GenericDef::from),
             GenericDef::Struct(_) | GenericDef::Enum(_) | GenericDef::Trait(_) => None,
             GenericDef::ImplBlock(_) => None,
         };
@@ -112,3 +109,12 @@ impl GenericParams {
         vec
     }
 }
+
+impl From<Container> for GenericDef {
+    fn from(c: Container) -> Self {
+        match c {
+            Container::Trait(trait_) => trait_.into(),
+            Container::ImplBlock(impl_block) => impl_block.into(),
+        }
+    }
+}
diff --git a/crates/ra_hir/src/impl_block.rs b/crates/ra_hir/src/impl_block.rs
index 42c02c9fb..71486aa2d 100644
--- a/crates/ra_hir/src/impl_block.rs
+++ b/crates/ra_hir/src/impl_block.rs
@@ -96,7 +96,7 @@ impl ImplBlock {
         db.generic_params((*self).into())
     }
 
-    pub(crate) fn resolver(&self, db: &impl HirDatabase) -> Resolver {
+    pub(crate) fn resolver(&self, db: &impl DefDatabase) -> Resolver {
         let r = self.module().resolver(db);
         // add generic params, if present
         let p = self.generic_params(db);
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index c284d1693..24e08f8cc 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -78,5 +78,5 @@ pub use self::code_model_api::{
     Function, FnSignature,
     StructField, FieldSource,
     Static, Const, ConstSignature,
-    Trait, TypeAlias,
+    Trait, TypeAlias, Container,
 };