From 3a748330af35ec9da4b07f55b78e8f08f2af0888 Mon Sep 17 00:00:00 2001
From: Nathan Stocks <cleancut@github.com>
Date: Thu, 22 Sep 2022 10:15:51 -0600
Subject: [PATCH] use cherry-picked commit from #100754 to emit note without
 error

---
 compiler/rustc_error_messages/locales/en-US/passes.ftl | 6 ++++--
 compiler/rustc_passes/src/errors.rs                    | 5 ++++-
 compiler/rustc_passes/src/weak_lang_items.rs           | 6 ++++--
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_error_messages/locales/en-US/passes.ftl b/compiler/rustc_error_messages/locales/en-US/passes.ftl
index 7dddc6e10b65..49cd2ee17588 100644
--- a/compiler/rustc_error_messages/locales/en-US/passes.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/passes.ftl
@@ -364,9 +364,11 @@ passes_unknown_external_lang_item =
 passes_missing_panic_handler =
     `#[panic_handler]` function required, but not found
 
-passes_missing_alloc_error_handler =
+passes_alloc_func_required =
     `#[alloc_error_handler]` function required, but not found
-    .note = use `#![feature(default_alloc_error_handler)]` for a default error handler
+
+passes_missing_alloc_error_handler =
+    use `#![feature(default_alloc_error_handler)]` for a default error handler
 
 passes_missing_lang_item =
     language item required, but not found: `{$name}`
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 0fabbb206cf9..26190af03587 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -690,9 +690,12 @@ pub struct UnknownExternLangItem {
 #[diag(passes::missing_panic_handler)]
 pub struct MissingPanicHandler;
 
+#[derive(Diagnostic)]
+#[diag(passes::alloc_func_required)]
+pub struct AllocFuncRequired;
+
 #[derive(Diagnostic)]
 #[diag(passes::missing_alloc_error_handler)]
-#[note]
 pub struct MissingAllocErrorHandler;
 
 #[derive(Diagnostic)]
diff --git a/compiler/rustc_passes/src/weak_lang_items.rs b/compiler/rustc_passes/src/weak_lang_items.rs
index 0d2745fb5f40..92024989a75e 100644
--- a/compiler/rustc_passes/src/weak_lang_items.rs
+++ b/compiler/rustc_passes/src/weak_lang_items.rs
@@ -8,7 +8,8 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::config::CrateType;
 
 use crate::errors::{
-    MissingAllocErrorHandler, MissingLangItem, MissingPanicHandler, UnknownExternLangItem,
+    AllocFuncRequired, MissingAllocErrorHandler, MissingLangItem, MissingPanicHandler,
+    UnknownExternLangItem,
 };
 
 /// Checks the crate for usage of weak lang items, returning a vector of all the
@@ -70,7 +71,8 @@ fn verify<'tcx>(tcx: TyCtxt<'tcx>, items: &lang_items::LanguageItems) {
                 tcx.sess.emit_err(MissingPanicHandler);
             } else if item == LangItem::Oom {
                 if !tcx.features().default_alloc_error_handler {
-                    tcx.sess.emit_err(MissingAllocErrorHandler);
+                    tcx.sess.emit_err(AllocFuncRequired);
+                    tcx.sess.emit_note(MissingAllocErrorHandler);
                 }
             } else {
                 tcx.sess.emit_err(MissingLangItem { name: *name });