From 7ef610c003f8072ec4ca4ecf195922a9a44e48dd Mon Sep 17 00:00:00 2001
From: David Wood <david.wood@huawei.com>
Date: Mon, 27 Jun 2022 17:11:53 +0100
Subject: [PATCH] lint: port drop trait/glue diagnostics

Signed-off-by: David Wood <david.wood@huawei.com>
---
 .../locales/en-US/lint.ftl                    |  6 ++++++
 compiler/rustc_lint/src/traits.rs             | 21 +++++++------------
 compiler/rustc_middle/src/ty/mod.rs           |  6 ++++++
 3 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/compiler/rustc_error_messages/locales/en-US/lint.ftl b/compiler/rustc_error_messages/locales/en-US/lint.ftl
index 511c0baaeca9..621af76f6958 100644
--- a/compiler/rustc_error_messages/locales/en-US/lint.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/lint.ftl
@@ -141,3 +141,9 @@ lint-redundant-semicolons =
         [true] these semicolons
         *[false] this semicolon
     }
+
+lint-drop-trait-constraints =
+    bounds on `{$predicate}` are most likely incorrect, consider instead using `{$needs_drop}` to detect whether a type can be trivially dropped
+
+lint-drop-glue =
+    types that do not implement `Drop` can still have drop glue, consider instead using `{$needs_drop}` to detect whether a type is trivially dropped
diff --git a/compiler/rustc_lint/src/traits.rs b/compiler/rustc_lint/src/traits.rs
index 81d308ee3470..df1587c5948f 100644
--- a/compiler/rustc_lint/src/traits.rs
+++ b/compiler/rustc_lint/src/traits.rs
@@ -1,6 +1,7 @@
 use crate::LateContext;
 use crate::LateLintPass;
 use crate::LintContext;
+use rustc_errors::fluent;
 use rustc_hir as hir;
 use rustc_span::symbol::sym;
 
@@ -103,13 +104,10 @@ impl<'tcx> LateLintPass<'tcx> for DropTraitConstraints {
                     let Some(needs_drop) = cx.tcx.get_diagnostic_item(sym::needs_drop) else {
                         return
                     };
-                    let msg = format!(
-                        "bounds on `{}` are most likely incorrect, consider instead \
-                         using `{}` to detect whether a type can be trivially dropped",
-                        predicate,
-                        cx.tcx.def_path_str(needs_drop)
-                    );
-                    lint.build(&msg).emit();
+                    lint.build(fluent::lint::drop_trait_constraints)
+                        .set_arg("predicate", predicate)
+                        .set_arg("needs_drop", cx.tcx.def_path_str(needs_drop))
+                        .emit();
                 });
             }
         }
@@ -126,12 +124,9 @@ impl<'tcx> LateLintPass<'tcx> for DropTraitConstraints {
                     let Some(needs_drop) = cx.tcx.get_diagnostic_item(sym::needs_drop) else {
                         return
                     };
-                    let msg = format!(
-                        "types that do not implement `Drop` can still have drop glue, consider \
-                        instead using `{}` to detect whether a type is trivially dropped",
-                        cx.tcx.def_path_str(needs_drop)
-                    );
-                    lint.build(&msg).emit();
+                    lint.build(fluent::lint::drop_glue)
+                        .set_arg("needs_drop", cx.tcx.def_path_str(needs_drop))
+                        .emit();
                 });
             }
         }
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 00403ff044c4..1b2d95073d06 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -611,6 +611,12 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {
     }
 }
 
+impl rustc_errors::IntoDiagnosticArg for Predicate<'_> {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        rustc_errors::DiagnosticArgValue::Str(std::borrow::Cow::Owned(self.to_string()))
+    }
+}
+
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
 #[derive(HashStable, TypeFoldable)]
 pub enum PredicateKind<'tcx> {