More minor fixes suggested by @jackh726

compiler/rustc_errors/src/diagnostic.rs

@@ -283,20 +283,12 @@ impl Diagnostic {
         suggestion: Vec<(Span, String)>,
         applicability: Applicability,
     ) -> &mut Self {
-        assert!(!suggestion.is_empty());
-        self.suggestions.push(CodeSuggestion {
-            substitutions: vec![Substitution {
-                parts: suggestion
-                    .into_iter()
-                    .map(|(span, snippet)| SubstitutionPart { snippet, span })
-                    .collect(),
-            }],
-            msg: msg.to_owned(),
-            style: SuggestionStyle::ShowCode,
+        self.multipart_suggestion_with_style(
+            msg,
+            suggestion,
             applicability,
-            tool_metadata: Default::default(),
-        });
-        self
+            SuggestionStyle::ShowCode,
+        )
     }
 
     /// [`Diagnostic::multipart_suggestion()`] but you can set the [`SuggestionStyle`].

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1905,9 +1905,11 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
 
                 let spans_suggs: Vec<_> = formatters
                     .into_iter()
-                    .filter_map(|fmt| fmt)
                     .zip(spans_with_counts.iter())
-                    .map(|(formatter, (span, _))| (*span, formatter(name)))
+                    .filter_map(|(fmt, (span, _))| {
+                        if let Some(formatter) = fmt { Some((formatter, span)) } else { None }
+                    })
+                    .map(|(formatter, span)| (*span, formatter(name)))
                     .collect();
                 err.multipart_suggestion_with_style(
                     &format!(