From 11825ac5fee8616ea7de2c80b5298978e7906bf1 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Sun, 23 May 2021 16:28:23 +0200
Subject: Explain why nested `TypeRef` aren't interned

---
 crates/hir_def/src/type_ref.rs | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'crates/hir_def/src')

diff --git a/crates/hir_def/src/type_ref.rs b/crates/hir_def/src/type_ref.rs
index 9e44547cb..cdcab7110 100644
--- a/crates/hir_def/src/type_ref.rs
+++ b/crates/hir_def/src/type_ref.rs
@@ -72,6 +72,10 @@ impl TraitRef {
 }
 
 /// Compare ty::Ty
+///
+/// Note: Most users of `TypeRef` that end up in the salsa database intern it using
+/// `Interned<TypeRef>` to save space. But notably, nested `TypeRef`s are not interned, since that
+/// does not seem to save any noticeable amount of memory.
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub enum TypeRef {
     Never,
-- 
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