From f564d7abba53648a92b2d1f654d920cf78afc0c6 Mon Sep 17 00:00:00 2001
From: Mark Rousskov <mark.simulacrum@gmail.com>
Date: Mon, 8 Feb 2021 17:20:41 -0500
Subject: [PATCH] Switch query descriptions to just String

In practice we never used the borrowed variant anyway.
---
 compiler/rustc_macros/src/query.rs              | 4 ++--
 compiler/rustc_middle/src/query/mod.rs          | 1 -
 compiler/rustc_middle/src/ty/query/mod.rs       | 1 -
 compiler/rustc_middle/src/ty/query/plumbing.rs  | 4 ++--
 compiler/rustc_query_system/src/query/config.rs | 3 +--
 5 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/compiler/rustc_macros/src/query.rs b/compiler/rustc_macros/src/query.rs
index cff8e983318..bd20c7689ea 100644
--- a/compiler/rustc_macros/src/query.rs
+++ b/compiler/rustc_macros/src/query.rs
@@ -417,8 +417,8 @@ fn cache_on_disk(
         fn describe(
             #tcx: TyCtxt<'tcx>,
             #key: #arg,
-        ) -> Cow<'static, str> {
-            ::rustc_middle::ty::print::with_no_trimmed_paths(|| format!(#desc).into())
+        ) -> String {
+            ::rustc_middle::ty::print::with_no_trimmed_paths(|| format!(#desc))
         }
     };
 
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index ca528b2f091..f3f3368b090 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -13,7 +13,6 @@
 use rustc_query_system::query::QueryDescription;
 
 use rustc_span::symbol::Symbol;
-use std::borrow::Cow;
 
 fn describe_as_module(def_id: LocalDefId, tcx: TyCtxt<'_>) -> String {
     if def_id.is_top_level_module() {
diff --git a/compiler/rustc_middle/src/ty/query/mod.rs b/compiler/rustc_middle/src/ty/query/mod.rs
index f580cb14dc9..804c045a690 100644
--- a/compiler/rustc_middle/src/ty/query/mod.rs
+++ b/compiler/rustc_middle/src/ty/query/mod.rs
@@ -53,7 +53,6 @@
 use rustc_attr as attr;
 use rustc_span::symbol::Symbol;
 use rustc_span::{Span, DUMMY_SP};
-use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::ops::Deref;
 use std::path::PathBuf;
diff --git a/compiler/rustc_middle/src/ty/query/plumbing.rs b/compiler/rustc_middle/src/ty/query/plumbing.rs
index d0730bd121c..46addcdaead 100644
--- a/compiler/rustc_middle/src/ty/query/plumbing.rs
+++ b/compiler/rustc_middle/src/ty/query/plumbing.rs
@@ -277,14 +277,14 @@ pub fn name(&self) -> &'static str {
                 }
             }
 
-            pub fn describe(&self, tcx: TyCtxt<$tcx>) -> Cow<'static, str> {
+            pub fn describe(&self, tcx: TyCtxt<$tcx>) -> String {
                 let (r, name) = match *self {
                     $(Query::$name(key) => {
                         (queries::$name::describe(tcx, key), stringify!($name))
                     })*
                 };
                 if tcx.sess.verbose() {
-                    format!("{} [{}]", r, name).into()
+                    format!("{} [{}]", r, name)
                 } else {
                     r
                 }
diff --git a/compiler/rustc_query_system/src/query/config.rs b/compiler/rustc_query_system/src/query/config.rs
index 0f0684b3547..94e906fc433 100644
--- a/compiler/rustc_query_system/src/query/config.rs
+++ b/compiler/rustc_query_system/src/query/config.rs
@@ -7,7 +7,6 @@
 use crate::query::{QueryContext, QueryState};
 
 use rustc_data_structures::fingerprint::Fingerprint;
-use std::borrow::Cow;
 use std::fmt::Debug;
 use std::hash::Hash;
 
@@ -95,7 +94,7 @@ fn hash_result(
 }
 
 pub trait QueryDescription<CTX: QueryContext>: QueryAccessors<CTX> {
-    fn describe(tcx: CTX, key: Self::Key) -> Cow<'static, str>;
+    fn describe(tcx: CTX, key: Self::Key) -> String;
 
     #[inline]
     fn cache_on_disk(_: CTX, _: &Self::Key, _: Option<&Self::Value>) -> bool {