diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 81e6b8da1d630..e83e10a68c325 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -734,7 +734,7 @@ impl Diagnostic {
         &mut self,
         sp: Span,
         msg: impl Into<SubdiagnosticMessage>,
-        suggestions: impl Iterator<Item = String>,
+        suggestions: impl IntoIterator<Item = String>,
         applicability: Applicability,
         style: SuggestionStyle,
     ) -> &mut Self {
@@ -768,7 +768,7 @@ impl Diagnostic {
         suggestions: impl IntoIterator<Item = Vec<(Span, String)>>,
         applicability: Applicability,
     ) -> &mut Self {
-        let suggestions: Vec<_> = suggestions.collect();
+        let suggestions: Vec<_> = suggestions.into_iter().collect();
         debug_assert!(
             !(suggestions
                 .iter()