From a9e13fa5533df7fc004aeab00d45822eacb8461e Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Thu, 10 Mar 2022 23:12:35 +0100
Subject: Lint elided lifetimes in path on the AST.

---
 compiler/rustc_errors/src/lib.rs | 38 ++++++++++----------------------------
 1 file changed, 10 insertions(+), 28 deletions(-)

(limited to 'compiler/rustc_errors/src')

diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 416bc4e2e3b..d7c5df7d8e2 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -1511,35 +1511,17 @@ pub fn add_elided_lifetime_in_path_suggestion(
     path_span: Span,
     incl_angl_brckt: bool,
     insertion_span: Span,
-    anon_lts: String,
 ) {
-    let (replace_span, suggestion) = if incl_angl_brckt {
-        (insertion_span, anon_lts)
-    } else {
-        // When possible, prefer a suggestion that replaces the whole
-        // `Path<T>` expression with `Path<'_, T>`, rather than inserting `'_, `
-        // at a point (which makes for an ugly/confusing label)
-        if let Ok(snippet) = source_map.span_to_snippet(path_span) {
-            // But our spans can get out of whack due to macros; if the place we think
-            // we want to insert `'_` isn't even within the path expression's span, we
-            // should bail out of making any suggestion rather than panicking on a
-            // subtract-with-overflow or string-slice-out-out-bounds (!)
-            // FIXME: can we do better?
-            if insertion_span.lo().0 < path_span.lo().0 {
-                return;
-            }
-            let insertion_index = (insertion_span.lo().0 - path_span.lo().0) as usize;
-            if insertion_index > snippet.len() {
-                return;
-            }
-            let (before, after) = snippet.split_at(insertion_index);
-            (path_span, format!("{}{}{}", before, anon_lts, after))
-        } else {
-            (insertion_span, anon_lts)
-        }
-    };
-    diag.span_suggestion(
-        replace_span,
+    diag.span_label(path_span, format!("expected lifetime parameter{}", pluralize!(n)));
+    if source_map.span_to_snippet(insertion_span).is_err() {
+        // Do not try to suggest anything if generated by a proc-macro.
+        return;
+    }
+    let anon_lts = vec!["'_"; n].join(", ");
+    let suggestion =
+        if incl_angl_brckt { format!("<{}>", anon_lts) } else { format!("{}, ", anon_lts) };
+    diag.span_suggestion_verbose(
+        insertion_span.shrink_to_hi(),
         &format!("indicate the anonymous lifetime{}", pluralize!(n)),
         suggestion,
         Applicability::MachineApplicable,
-- 
cgit 1.4.1-3-g733a5