From 17a4a68ab0ffa0e8736d5ccf71f6e56794a0320a Mon Sep 17 00:00:00 2001
From: rdvdev2 <rdvdev2@gmail.com>
Date: Fri, 2 Sep 2022 00:11:44 +0200
Subject: [PATCH] Migrate derivable diagnostics in lang_items.rs

---
 .../locales/en-US/passes.ftl                  |  8 +++++
 compiler/rustc_passes/src/errors.rs           | 21 +++++++++++++
 compiler/rustc_passes/src/lang_items.rs       | 30 +++++--------------
 3 files changed, 37 insertions(+), 22 deletions(-)

diff --git a/compiler/rustc_error_messages/locales/en-US/passes.ftl b/compiler/rustc_error_messages/locales/en-US/passes.ftl
index bfe22727483..6512af1d14c 100644
--- a/compiler/rustc_error_messages/locales/en-US/passes.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/passes.ftl
@@ -280,3 +280,11 @@ passes_missing_alloc_error_handler = `#[alloc_error_handler]` function required,
 passes_missing_lang_item = language item required, but not found: `{$name}`
     .note = this can occur when a binary crate with `#![no_std]` is compiled for a target where `{$name}` is defined in the standard library
     .help = you may be able to compile for a target that doesn't need `{$name}`, specify a target with `--target` or in `.cargo/config`
+
+passes_lang_item_on_incorrect_target = `{$name}` language item must be applied to a {$expected_target}
+    .label = attribute should be applied to a {$expected_target}, not a {$actual_target}
+
+passes_unknown_lang_item = definition of an unknown language item: `{$name}`
+    .label = definition of unknown language item `{$name}`
+
+passes_local_duplicate_lang_item = found duplicate lang item `{$name}`
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 7dbdee8a87a..cd05784cd53 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -1,4 +1,5 @@
 use rustc_errors::{Applicability, MultiSpan};
+use rustc_hir::Target;
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
@@ -682,3 +683,23 @@ pub struct MissingAllocErrorHandler;
 pub struct MissingLangItem {
     pub name: Symbol,
 }
+
+#[derive(Diagnostic)]
+#[diag(passes::lang_item_on_incorrect_target, code = "E0718")]
+pub struct LangItemOnIncorrectTarget {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub name: Symbol,
+    pub expected_target: Target,
+    pub actual_target: Target,
+}
+
+#[derive(Diagnostic)]
+#[diag(passes::unknown_lang_item, code = "E0522")]
+pub struct UnknownLangItem {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub name: Symbol,
+}
diff --git a/compiler/rustc_passes/src/lang_items.rs b/compiler/rustc_passes/src/lang_items.rs
index 79900a90aed..98ff625d094 100644
--- a/compiler/rustc_passes/src/lang_items.rs
+++ b/compiler/rustc_passes/src/lang_items.rs
@@ -7,6 +7,7 @@
 //! * Traits that represent operators; e.g., `Add`, `Sub`, `Index`.
 //! * Functions called by the compiler itself.
 
+use crate::errors::{LangItemOnIncorrectTarget, UnknownLangItem};
 use crate::check_attr::target_from_impl_item;
 use crate::weak_lang_items;
 
@@ -42,34 +43,19 @@ impl<'tcx> LanguageItemCollector<'tcx> {
                 }
                 // Known lang item with attribute on incorrect target.
                 Some((_, expected_target)) => {
-                    struct_span_err!(
-                        self.tcx.sess,
+                    self.tcx.sess.emit_err(LangItemOnIncorrectTarget {
                         span,
-                        E0718,
-                        "`{}` language item must be applied to a {}",
-                        value,
+                        name: value,
                         expected_target,
-                    )
-                    .span_label(
-                        span,
-                        format!(
-                            "attribute should be applied to a {}, not a {}",
-                            expected_target, actual_target,
-                        ),
-                    )
-                    .emit();
+                        actual_target,
+                    });
                 }
                 // Unknown lang item.
                 _ => {
-                    struct_span_err!(
-                        self.tcx.sess,
+                    self.tcx.sess.emit_err(UnknownLangItem {
                         span,
-                        E0522,
-                        "definition of an unknown language item: `{}`",
-                        value
-                    )
-                    .span_label(span, format!("definition of unknown language item `{}`", value))
-                    .emit();
+                        name: value,
+                    });
                 }
             }
         }