Rollup merge of #130149 - GrigorenkoPV:lifetime-suggestion, r=cjgillot

Helper function for formatting with `LifetimeSuggestionPosition`

Author: workingjubilee

compiler/rustc_hir/src/hir.rs

@@ -168,6 +168,19 @@ impl Lifetime {
             (LifetimeSuggestionPosition::Normal, self.ident.span)
         }
     }
+
+    pub fn suggestion(&self, new_lifetime: &str) -> (Span, String) {
+        debug_assert!(new_lifetime.starts_with('\''));
+        let (pos, span) = self.suggestion_position();
+        let code = match pos {
+            LifetimeSuggestionPosition::Normal => format!("{new_lifetime}"),
+            LifetimeSuggestionPosition::Ampersand => format!("{new_lifetime} "),
+            LifetimeSuggestionPosition::ElidedPath => format!("<{new_lifetime}>"),
+            LifetimeSuggestionPosition::ElidedPathArgument => format!("{new_lifetime}, "),
+            LifetimeSuggestionPosition::ObjectDefault => format!("+ {new_lifetime}"),
+        };
+        (span, code)
+    }
 }
 
 /// A `Path` is essentially Rust's notion of a name; for instance,

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -1191,23 +1191,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                                     (generics.span, "<'a>".to_owned())
                                 };
 
-                            let lifetime_sugg = match lifetime_ref.suggestion_position() {
-                                (hir::LifetimeSuggestionPosition::Normal, span) => {
-                                    (span, "'a".to_owned())
-                                }
-                                (hir::LifetimeSuggestionPosition::Ampersand, span) => {
-                                    (span, "'a ".to_owned())
-                                }
-                                (hir::LifetimeSuggestionPosition::ElidedPath, span) => {
-                                    (span, "<'a>".to_owned())
-                                }
-                                (hir::LifetimeSuggestionPosition::ElidedPathArgument, span) => {
-                                    (span, "'a, ".to_owned())
-                                }
-                                (hir::LifetimeSuggestionPosition::ObjectDefault, span) => {
-                                    (span, "+ 'a".to_owned())
-                                }
-                            };
+                            let lifetime_sugg = lifetime_ref.suggestion("'a");
                             let suggestions = vec![lifetime_sugg, new_param_sugg];
 
                             diag.span_label(

compiler/rustc_trait_selection/src/error_reporting/infer/region.rs

@@ -852,18 +852,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         impl<'hir, 'tcx> hir::intravisit::Visitor<'hir> for LifetimeReplaceVisitor<'tcx, '_> {
             fn visit_lifetime(&mut self, lt: &'hir hir::Lifetime) {
                 if lt.res == self.needle {
-                    let (pos, span) = lt.suggestion_position();
-                    let new_lt = &self.new_lt;
-                    let sugg = match pos {
-                        hir::LifetimeSuggestionPosition::Normal => format!("{new_lt}"),
-                        hir::LifetimeSuggestionPosition::Ampersand => format!("{new_lt} "),
-                        hir::LifetimeSuggestionPosition::ElidedPath => format!("<{new_lt}>"),
-                        hir::LifetimeSuggestionPosition::ElidedPathArgument => {
-                            format!("{new_lt}, ")
-                        }
-                        hir::LifetimeSuggestionPosition::ObjectDefault => format!("+ {new_lt}"),
-                    };
-                    self.add_lt_suggs.push((span, sugg));
+                    self.add_lt_suggs.push(lt.suggestion(self.new_lt));
                 }
             }