Merge #623

623: WIP: module id is not def id r=matklad a=matklad

This achieves two things:

* makes module_tree & item_map per crate, not per source_root
* begins the refactoring to remove universal `DefId` in favor of having separate ids for each kind of `Def`. Currently, only modules get a differnt ID though. 

Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

crates/ra_syntax/src/ast.rs

@@ -430,6 +430,13 @@ impl StructDef {
 }
 
 impl EnumVariant {
+    pub fn parent_enum(&self) -> &EnumDef {
+        self.syntax()
+            .parent()
+            .and_then(|it| it.parent())
+            .and_then(EnumDef::cast)
+            .expect("EnumVariants are always nested in Enums")
+    }
     pub fn flavor(&self) -> StructFlavor {
         StructFlavor::from_node(self)
     }

crates/ra_syntax/src/ast/generated.rs

@@ -3229,6 +3229,7 @@ impl ast::VisibilityOwner for TraitDef {}
 impl ast::NameOwner for TraitDef {}
 impl ast::AttrsOwner for TraitDef {}
 impl ast::DocCommentsOwner for TraitDef {}
+impl ast::TypeParamsOwner for TraitDef {}
 impl TraitDef {}
 
 // TrueKw

crates/ra_syntax/src/grammar.ron

@@ -280,7 +280,7 @@ Grammar(
         ], options: [["variant_list", "EnumVariantList"]] ),
         "EnumVariantList": ( collections: [["variants", "EnumVariant"]] ),
         "EnumVariant": ( traits: ["NameOwner", "DocCommentsOwner"], options: ["Expr"] ),
-        "TraitDef": ( traits: ["VisibilityOwner", "NameOwner", "AttrsOwner", "DocCommentsOwner"] ),
+        "TraitDef": ( traits: ["VisibilityOwner", "NameOwner", "AttrsOwner", "DocCommentsOwner", "TypeParamsOwner"] ),
         "Module": (
             traits: ["VisibilityOwner", "NameOwner", "AttrsOwner", "DocCommentsOwner" ],
             options: [ "ItemList" ]
@@ -489,7 +489,7 @@ Grammar(
         ),
 
         "RefPat": ( options: [ "Pat" ]),
-        "BindPat": ( 
+        "BindPat": (
             options: [ "Pat" ],
             traits: ["NameOwner"]
         ),