4 files changed, 49 insertions, 27 deletions

diff --git a/crates/ra_assists/src/assists/add_new.rs b/crates/ra_assists/src/assists/add_new.rs
index aedcd6286..8db63f762 100644
--- a/crates/ra_assists/src/assists/add_new.rs
+++ b/crates/ra_assists/src/assists/add_new.rs
@@ -140,12 +140,12 @@ fn find_struct_impl(
 
     let struct_ty = {
         let src = InFile { file_id: ctx.frange.file_id.into(), value: strukt.clone() };
-        sb.to_def::<hir::Struct, _>(src)?.ty(db)
+        sb.to_def(src)?.ty(db)
     };
 
     let block = module.descendants().filter_map(ast::ImplBlock::cast).find_map(|impl_blk| {
         let src = InFile { file_id: ctx.frange.file_id.into(), value: impl_blk.clone() };
-        let blk = sb.to_def::<hir::ImplBlock, _>(src)?;
+        let blk = sb.to_def(src)?;
 
         let same_ty = blk.target_ty(db) == struct_ty;
         let not_trait_impl = blk.target_trait(db).is_none();
diff --git a/crates/ra_hir/src/from_source.rs b/crates/ra_hir/src/from_source.rs
index 30e818892..caaff012a 100644
--- a/crates/ra_hir/src/from_source.rs
+++ b/crates/ra_hir/src/from_source.rs
@@ -14,8 +14,7 @@ use ra_syntax::{
 
 use crate::{
     db::{DefDatabase, HirDatabase},
-    Const, DefWithBody, Enum, Function, ImplBlock, InFile, Local, Module, SourceBinder, Static,
-    Struct, Trait, TypeAlias, TypeParam,
+    DefWithBody, InFile, Local, Module, SourceBinder, TypeParam,
 };
 
 impl Local {
@@ -25,9 +24,9 @@ impl Local {
         let parent: DefWithBody = src.value.syntax().ancestors().find_map(|it| {
             let res = match_ast! {
                 match it {
-                    ast::ConstDef(value) => { sb.to_def::<Const, _>(InFile { value, file_id})?.into() },
-                    ast::StaticDef(value) => { sb.to_def::<Static, _>(InFile { value, file_id})?.into() },
-                    ast::FnDef(value) => { sb.to_def::<Function, _>(InFile { value, file_id})?.into() },
+                    ast::ConstDef(value) => { sb.to_def(InFile { value, file_id})?.into() },
+                    ast::StaticDef(value) => { sb.to_def(InFile { value, file_id})?.into() },
+                    ast::FnDef(value) => { sb.to_def(InFile { value, file_id})?.into() },
                     _ => return None,
                 }
             };
@@ -47,12 +46,12 @@ impl TypeParam {
         let parent: GenericDefId = src.value.syntax().ancestors().find_map(|it| {
             let res = match_ast! {
                 match it {
-                    ast::FnDef(value) => { sb.to_def::<Function, _>(InFile { value, file_id})?.id.into() },
-                    ast::StructDef(value) => { sb.to_def::<Struct, _>(InFile { value, file_id})?.id.into() },
-                    ast::EnumDef(value) => { sb.to_def::<Enum, _>(InFile { value, file_id})?.id.into() },
-                    ast::TraitDef(value) => { sb.to_def::<Trait, _>(InFile { value, file_id})?.id.into() },
-                    ast::TypeAliasDef(value) => { sb.to_def::<TypeAlias, _>(InFile { value, file_id})?.id.into() },
-                    ast::ImplBlock(value) => { sb.to_def::<ImplBlock, _>(InFile { value, file_id})?.id.into() },
+                    ast::FnDef(value) => { sb.to_def(InFile { value, file_id})?.id.into() },
+                    ast::StructDef(value) => { sb.to_def(InFile { value, file_id})?.id.into() },
+                    ast::EnumDef(value) => { sb.to_def(InFile { value, file_id})?.id.into() },
+                    ast::TraitDef(value) => { sb.to_def(InFile { value, file_id})?.id.into() },
+                    ast::TypeAliasDef(value) => { sb.to_def(InFile { value, file_id})?.id.into() },
+                    ast::ImplBlock(value) => { sb.to_def(InFile { value, file_id})?.id.into() },
                     _ => return None,
                 }
             };
diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index 66930e492..c02175c06 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -52,11 +52,7 @@ impl<DB: HirDatabase> SourceBinder<'_, DB> {
         SourceAnalyzer::new_for_resolver(resolver, src)
     }
 
-    pub fn to_def<D, T>(&mut self, src: InFile<T>) -> Option<D>
-    where
-        D: From<T::ID>,
-        T: ToId,
-    {
+    pub fn to_def<T: ToDef>(&mut self, src: InFile<T>) -> Option<T::Def> {
         let id: T::ID = self.to_id(src)?;
         Some(id.into())
     }
@@ -114,6 +110,39 @@ impl<DB: HirDatabase> SourceBinder<'_, DB> {
     }
 }
 
+pub trait ToId: Sized + AstNode + 'static {
+    type ID: Sized + Copy + 'static;
+    fn to_id<DB: HirDatabase>(sb: &mut SourceBinder<'_, DB>, src: InFile<Self>)
+        -> Option<Self::ID>;
+}
+
+pub trait ToDef: ToId {
+    type Def: From<Self::ID>;
+}
+
+macro_rules! to_def_impls {
+    ($(($def:path, $ast:path)),* ,) => {$(
+        impl ToDef for $ast {
+            type Def = $def;
+        }
+    )*}
+}
+
+to_def_impls![
+    (crate::Struct, ast::StructDef),
+    (crate::Enum, ast::EnumDef),
+    (crate::Union, ast::UnionDef),
+    (crate::Trait, ast::TraitDef),
+    (crate::ImplBlock, ast::ImplBlock),
+    (crate::TypeAlias, ast::TypeAliasDef),
+    (crate::Const, ast::ConstDef),
+    (crate::Static, ast::StaticDef),
+    (crate::Function, ast::FnDef),
+    (crate::StructField, ast::RecordFieldDef),
+    (crate::EnumVariant, ast::EnumVariant),
+    (crate::MacroDef, ast::MacroCall), // this one is dubious, not all calls are macros
+];
+
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
 enum ChildContainer {
     DefWithBodyId(DefWithBodyId),
@@ -133,12 +162,6 @@ impl_froms! {
     VariantId,
 }
 
-pub trait ToId: Sized + AstNode + 'static {
-    type ID: Sized + Copy + 'static;
-    fn to_id<DB: HirDatabase>(sb: &mut SourceBinder<'_, DB>, src: InFile<Self>)
-        -> Option<Self::ID>;
-}
-
 pub trait ToIdByKey: Sized + AstNode + 'static {
     type ID: Sized + Copy + 'static;
     const KEY: Key<Self, Self::ID>;
diff --git a/crates/ra_ide/src/impls.rs b/crates/ra_ide/src/impls.rs
index bd14a6d13..fb9396195 100644
--- a/crates/ra_ide/src/impls.rs
+++ b/crates/ra_ide/src/impls.rs
@@ -44,15 +44,15 @@ fn impls_for_def(
     let ty = match node {
         ast::NominalDef::StructDef(def) => {
             let src = hir::InFile { file_id: position.file_id.into(), value: def.clone() };
-            sb.to_def::<hir::Struct, _>(src)?.ty(sb.db)
+            sb.to_def(src)?.ty(sb.db)
         }
         ast::NominalDef::EnumDef(def) => {
             let src = hir::InFile { file_id: position.file_id.into(), value: def.clone() };
-            sb.to_def::<hir::Enum, _>(src)?.ty(sb.db)
+            sb.to_def(src)?.ty(sb.db)
         }
         ast::NominalDef::UnionDef(def) => {
             let src = hir::InFile { file_id: position.file_id.into(), value: def.clone() };
-            sb.to_def::<hir::Union, _>(src)?.ty(sb.db)
+            sb.to_def(src)?.ty(sb.db)
         }
     };