From de184a63a64127516468fea9cf5f662974e5bcf6 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume.gomez@huawei.com>
Date: Tue, 13 Sep 2022 17:27:56 +0200
Subject: [PATCH] Add documentation for TyCtxt::visibility

---
 compiler/rustc_middle/src/query/mod.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index f72e7389fc606..e7e039d80de1e 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1611,6 +1611,16 @@ rustc_queries! {
         desc { "looking up late bound vars" }
     }
 
+    /// Computes the visibility of the provided `def_id`.
+    ///
+    /// If the item from the `def_id` doesn't have a visibility, it will panic. For example
+    /// a generic type parameter will panic if you call this method on it:
+    ///
+    /// ```
+    /// pub trait Foo<T: Debug> {}
+    /// ```
+    ///
+    /// In here, if you call `visibility` on `T`, it'll panic.
     query visibility(def_id: DefId) -> ty::Visibility<DefId> {
         desc { |tcx| "computing visibility of `{}`", tcx.def_path_str(def_id) }
         separate_provide_extern