diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 21515aa3b9f62..5346dcccdc71f 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -835,12 +835,12 @@ impl From<NestedSpan> for FieldDeclSpan {
 
 struct FieldUniquenessCheckContext<'tcx> {
     tcx: TyCtxt<'tcx>,
-    seen_fields: FxHashMap<Ident, FieldDeclSpan>,
+    seen_fields: FxIndexMap<Ident, FieldDeclSpan>,
 }
 
 impl<'tcx> FieldUniquenessCheckContext<'tcx> {
     fn new(tcx: TyCtxt<'tcx>) -> Self {
-        Self { tcx, seen_fields: FxHashMap::default() }
+        Self { tcx, seen_fields: FxIndexMap::default() }
     }
 
     /// Check if a given field `ident` declared at `field_decl` has been declared elsewhere before.