diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs
index 82fe2a21d0876..ab8015c4a43b6 100644
--- a/compiler/rustc_ast_passes/src/errors.rs
+++ b/compiler/rustc_ast_passes/src/errors.rs
@@ -77,13 +77,6 @@ pub struct ForbiddenLifetimeBound {
     pub spans: Vec<Span>,
 }
 
-#[derive(Diagnostic)]
-#[diag(ast_passes_forbidden_non_lifetime_param)]
-pub struct ForbiddenNonLifetimeParam {
-    #[primary_span]
-    pub spans: Vec<Span>,
-}
-
 #[derive(Diagnostic)]
 #[diag(ast_passes_fn_param_too_many)]
 pub struct FnParamTooMany {
diff --git a/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs b/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs
index 2a32f0b504737..7293de4c6c5e5 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs
@@ -139,7 +139,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                                     tcx,
                                     generics,
                                     diag,
-                                    &format!("{}", proj.self_ty()),
+                                    &proj.self_ty().to_string(),
                                     &path,
                                     None,
                                     matching_span,
@@ -153,7 +153,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                                     tcx,
                                     generics,
                                     diag,
-                                    &format!("{}", proj.self_ty()),
+                                    &proj.self_ty().to_string(),
                                     &path,
                                     None,
                                     matching_span,