Merge #3656

3656: Simplify arenas r=matklad a=matklad

At the moment, Arena is paranetrized by two types: index and data. The original motivation was to allow index to be defined in the downstream crate, so that you can add inherent impls to the index. 

However, it seems like we've never actually used that capability, so perhaps we should switch to a generic Index impl? This PR tries this out, switching only `raw.rs` and parts of `hir_def`. 

wdyt?

Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/crates/ra_hir_def/src/nameres.rs b/crates/ra_hir_def/src/nameres.rs
index be53313ee..40bdc34f5 100644
--- a/crates/ra_hir_def/src/nameres.rs
+++ b/crates/ra_hir_def/src/nameres.rs
@@ -77,7 +77,7 @@ use crate::{
 #[derive(Debug, PartialEq, Eq)]
 pub struct CrateDefMap {
     pub root: LocalModuleId,
-    pub modules: Arena<LocalModuleId, ModuleData>,
+    pub modules: Arena<ModuleData>,
     pub(crate) krate: CrateId,
     /// The prelude module for this crate. This either comes from an import
     /// marked with the `prelude_import` attribute, or (in the normal case) from
@@ -187,7 +187,7 @@ impl CrateDefMap {
         });
         let def_map = {
             let edition = db.crate_graph()[krate].edition;
-            let mut modules: Arena<LocalModuleId, ModuleData> = Arena::default();
+            let mut modules: Arena<ModuleData> = Arena::default();
             let root = modules.alloc(ModuleData::default());
             CrateDefMap {
                 krate,