7 files changed, 33 insertions, 37 deletions

diff --git a/crates/ra_hir/src/code_model_api.rs b/crates/ra_hir/src/code_model_api.rs
index 28de9e76a..8f1ed1086 100644
--- a/crates/ra_hir/src/code_model_api.rs
+++ b/crates/ra_hir/src/code_model_api.rs
@@ -11,7 +11,7 @@ use crate::{
     expr::{Body, BodySourceMap},
     ty::InferenceResult,
     adt::{EnumVariantId, StructFieldId, VariantDef},
-    generics::GenericParams,
+    generics::HasGenericParams,
     docs::{Documentation, Docs, docs_from_ast},
     ids::{FunctionId, StructId, EnumId, AstItemDef, ConstId, StaticId, TraitId, TypeAliasId},
     impl_block::ImplBlock,
@@ -299,10 +299,6 @@ impl Struct {
             .map(|(id, _)| StructField { parent: (*self).into(), id })
     }
 
-    pub fn generic_params(&self, db: &impl DefDatabase) -> Arc<GenericParams> {
-        db.generic_params((*self).into())
-    }
-
     pub fn ty(&self, db: &impl HirDatabase) -> Ty {
         db.type_for_def((*self).into(), Namespace::Types)
     }
@@ -363,10 +359,6 @@ impl Enum {
             .map(|(id, _)| EnumVariant { parent: *self, id })
     }
 
-    pub fn generic_params(&self, db: &impl DefDatabase) -> Arc<GenericParams> {
-        db.generic_params((*self).into())
-    }
-
     pub fn ty(&self, db: &impl HirDatabase) -> Ty {
         db.type_for_def((*self).into(), Namespace::Types)
     }
@@ -537,10 +529,6 @@ impl Function {
         db.infer((*self).into())
     }
 
-    pub fn generic_params(&self, db: &impl DefDatabase) -> Arc<GenericParams> {
-        db.generic_params((*self).into())
-    }
-
     /// The containing impl block, if this is a method.
     pub fn impl_block(&self, db: &impl DefDatabase) -> Option<ImplBlock> {
         let module_impls = db.impls_in_module(self.module(db));
@@ -696,10 +684,6 @@ impl Trait {
         self.id.module(db)
     }
 
-    pub fn generic_params(&self, db: &impl DefDatabase) -> Arc<GenericParams> {
-        db.generic_params((*self).into())
-    }
-
     pub fn name(self, db: &impl DefDatabase) -> Option<Name> {
         self.trait_data(db).name().clone()
     }
@@ -737,10 +721,6 @@ impl TypeAlias {
         self.id.source(db)
     }
 
-    pub fn generic_params(&self, db: &impl DefDatabase) -> Arc<GenericParams> {
-        db.generic_params((*self).into())
-    }
-
     pub fn module(&self, db: &impl DefDatabase) -> Module {
         self.id.module(db)
     }
diff --git a/crates/ra_hir/src/generics.rs b/crates/ra_hir/src/generics.rs
index f92b146ef..5625c2459 100644
--- a/crates/ra_hir/src/generics.rs
+++ b/crates/ra_hir/src/generics.rs
@@ -118,3 +118,16 @@ impl From<Container> for GenericDef {
         }
     }
 }
+
+pub trait HasGenericParams {
+    fn generic_params(self, db: &impl DefDatabase) -> Arc<GenericParams>;
+}
+
+impl<T> HasGenericParams for T
+where
+    T: Into<GenericDef>,
+{
+    fn generic_params(self, db: &impl DefDatabase) -> Arc<GenericParams> {
+        db.generic_params(self.into())
+    }
+}
diff --git a/crates/ra_hir/src/impl_block.rs b/crates/ra_hir/src/impl_block.rs
index 71486aa2d..a8a466e43 100644
--- a/crates/ra_hir/src/impl_block.rs
+++ b/crates/ra_hir/src/impl_block.rs
@@ -9,12 +9,13 @@ use ra_syntax::{
 
 use crate::{
     Const, TypeAlias, Function, HirFileId,
-    HirDatabase, DefDatabase,
+    HirDatabase, DefDatabase, TraitRef,
     type_ref::TypeRef,
     ids::LocationCtx,
     resolve::Resolver,
-    ty::Ty, generics::GenericParams,
-    TraitRef, code_model_api::{Module, ModuleSource}
+    ty::Ty,
+    generics::HasGenericParams,
+    code_model_api::{Module, ModuleSource}
 };
 
 #[derive(Debug, Default, PartialEq, Eq)]
@@ -92,10 +93,6 @@ impl ImplBlock {
         db.impls_in_module(self.module).impls[self.impl_id].items().to_vec()
     }
 
-    pub fn generic_params(&self, db: &impl DefDatabase) -> Arc<GenericParams> {
-        db.generic_params((*self).into())
-    }
-
     pub(crate) fn resolver(&self, db: &impl DefDatabase) -> Resolver {
         let r = self.module().resolver(db);
         // add generic params, if present
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 24e08f8cc..9292de1b5 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -67,6 +67,7 @@ pub use self::{
     adt::AdtDef,
     expr::ExprScopes,
     resolve::Resolution,
+    generics::{GenericParams, GenericParam, HasGenericParams},
     source_binder::{SourceAnalyzer, PathResolution, ScopeEntryWithSyntax},
 };
 
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 28459d750..651a78fe5 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -20,9 +20,9 @@ use std::sync::Arc;
 use std::mem;
 
 use ena::unify::{InPlaceUnificationTable, UnifyKey, UnifyValue, NoError};
-use ra_arena::map::ArenaMap;
 use rustc_hash::FxHashMap;
 
+use ra_arena::map::ArenaMap;
 use test_utils::tested_by;
 
 use crate::{
@@ -33,15 +33,18 @@ use crate::{
     ImplItem,
     type_ref::{TypeRef, Mutability},
     expr::{Body, Expr, BindingAnnotation, Literal, ExprId, Pat, PatId, UnaryOp, BinaryOp, Statement, FieldPat,Array, self},
-    generics::GenericParams,
+    generics::{GenericParams, HasGenericParams},
     path::{GenericArgs, GenericArg},
     adt::VariantDef,
     resolve::{Resolver, Resolution},
     nameres::Namespace,
-    ty::infer::diagnostics::InferenceDiagnostic,
     diagnostics::DiagnosticSink,
 };
-use super::{Ty, TypableDef, Substs, primitive, op, ApplicationTy, TypeCtor, traits::{ Solution, Obligation, Guidance}, CallableDef, TraitRef};
+use super::{
+    Ty, TypableDef, Substs, primitive, op, ApplicationTy, TypeCtor, CallableDef, TraitRef,
+    traits::{ Solution, Obligation, Guidance},
+};
+use self::diagnostics::InferenceDiagnostic;
 
 /// The entry point of type inference.
 pub fn infer(db: &impl HirDatabase, def: DefWithBody) -> Arc<InferenceResult> {
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index bb8fdd8c7..7fac084ce 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -16,8 +16,8 @@ use crate::{
     name::KnownName,
     nameres::Namespace,
     resolve::{Resolver, Resolution},
-    path::{ PathSegment, GenericArg},
-    generics::GenericParams,
+    path::{PathSegment, GenericArg},
+    generics::{GenericParams, HasGenericParams},
     adt::VariantDef, Trait
 };
 use super::{Ty, primitive, FnSig, Substs, TypeCtor, TraitRef};
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 126edeaff..6b7918187 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -10,10 +10,12 @@ use crate::{
     HirDatabase, Module, Crate, Name, Function, Trait,
     impl_block::{ImplId, ImplBlock, ImplItem},
     ty::{Ty, TypeCtor},
-    nameres::CrateModuleId, resolve::Resolver, traits::TraitItem
-
+    nameres::CrateModuleId,
+    resolve::Resolver,
+    traits::TraitItem,
+    generics::HasGenericParams,
 };
-use super::{ TraitRef, Substs};
+use super::{TraitRef, Substs};
 
 /// This is used as a key for indexing impls.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]