From c63ba52562a0c6c8d19b320c558d437bb8d87bd8 Mon Sep 17 00:00:00 2001
From: Rejyr <jerrylwang123@gmail.com>
Date: Sun, 18 Sep 2022 10:03:35 -0400
Subject: [PATCH] migrate: `array_into_iter.rs`

---
 compiler/rustc_lint/src/array_into_iter.rs | 52 ++++++++--------------
 compiler/rustc_lint/src/lints.rs           | 32 ++++++++++---
 2 files changed, 45 insertions(+), 39 deletions(-)

diff --git a/compiler/rustc_lint/src/array_into_iter.rs b/compiler/rustc_lint/src/array_into_iter.rs
index abebc533cc1..ea5975ed4f0 100644
--- a/compiler/rustc_lint/src/array_into_iter.rs
+++ b/compiler/rustc_lint/src/array_into_iter.rs
@@ -1,5 +1,7 @@
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
+use crate::lints::{ArrayIntoIterDiag, ArrayIntoIterDiagSub};
 use crate::{LateContext, LateLintPass, LintContext};
-use rustc_errors::{fluent, Applicability};
 use rustc_hir as hir;
 use rustc_middle::ty;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment};
@@ -118,41 +120,23 @@ impl<'tcx> LateLintPass<'tcx> for ArrayIntoIter {
                 // to an array or to a slice.
                 _ => bug!("array type coerced to something other than array or slice"),
             };
-            cx.struct_span_lint(
+            let sub = if self.for_expr_span == expr.span {
+                Some(ArrayIntoIterDiagSub::RemoveIntoIter {
+                    span: receiver_arg.span.shrink_to_hi().to(expr.span.shrink_to_hi()),
+                })
+            } else if receiver_ty.is_array() {
+                Some(ArrayIntoIterDiagSub::UseExplicitIntoIter {
+                    start_span: expr.span.shrink_to_lo(),
+                    end_span: receiver_arg.span.shrink_to_hi().to(expr.span.shrink_to_hi()),
+                })
+            } else {
+                None
+            };
+            cx.emit_spanned_lint(
                 ARRAY_INTO_ITER,
                 call.ident.span,
-                fluent::lint_array_into_iter,
-                |diag| {
-                    diag.set_arg("target", target);
-                    diag.span_suggestion(
-                        call.ident.span,
-                        fluent::use_iter_suggestion,
-                        "iter",
-                        Applicability::MachineApplicable,
-                    );
-                    if self.for_expr_span == expr.span {
-                        diag.span_suggestion(
-                            receiver_arg.span.shrink_to_hi().to(expr.span.shrink_to_hi()),
-                            fluent::remove_into_iter_suggestion,
-                            "",
-                            Applicability::MaybeIncorrect,
-                        );
-                    } else if receiver_ty.is_array() {
-                        diag.multipart_suggestion(
-                            fluent::use_explicit_into_iter_suggestion,
-                            vec![
-                                (expr.span.shrink_to_lo(), "IntoIterator::into_iter(".into()),
-                                (
-                                    receiver_arg.span.shrink_to_hi().to(expr.span.shrink_to_hi()),
-                                    ")".into(),
-                                ),
-                            ],
-                            Applicability::MaybeIncorrect,
-                        );
-                    }
-                    diag
-                },
-            )
+                ArrayIntoIterDiag { target, suggestion: call.ident.span, sub },
+            );
         }
     }
 }
diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
index 8ad62672f6e..9bfd000351a 100644
--- a/compiler/rustc_lint/src/lints.rs
+++ b/compiler/rustc_lint/src/lints.rs
@@ -6,6 +6,32 @@ use rustc_span::{symbol::Ident, Span, Symbol};
 
 use crate::LateContext;
 
+#[derive(LintDiagnostic)]
+#[diag(lint_array_into_iter)]
+pub struct ArrayIntoIterDiag<'a> {
+    pub target: &'a str,
+    #[suggestion(use_iter_suggestion, code = "iter", applicability = "machine-applicable")]
+    pub suggestion: Span,
+    #[subdiagnostic]
+    pub sub: Option<ArrayIntoIterDiagSub>,
+}
+
+#[derive(SessionSubdiagnostic)]
+pub enum ArrayIntoIterDiagSub {
+    #[suggestion(remove_into_iter_suggestion, code = "", applicability = "maybe-incorrect")]
+    RemoveIntoIter {
+        #[primary_span]
+        span: Span,
+    },
+    #[multipart_suggestion(use_explicit_into_iter_suggestion, applicability = "maybe-incorrect")]
+    UseExplicitIntoIter {
+        #[suggestion_part(code = "IntoIterator::into_iter(")]
+        start_span: Span,
+        #[suggestion_part(code = ")")]
+        end_span: Span,
+    },
+}
+
 #[derive(LintDiagnostic)]
 #[diag(lint_cstring_ptr)]
 #[note]
@@ -454,11 +480,7 @@ pub struct PathStatementDrop {
 
 #[derive(SessionSubdiagnostic)]
 pub enum PathStatementDropSub {
-    #[suggestion(
-        suggestion,
-        code = "drop({snippet});",
-        applicability = "machine-applicable"
-    )]
+    #[suggestion(suggestion, code = "drop({snippet});", applicability = "machine-applicable")]
     Suggestion {
         #[primary_span]
         span: Span,