Do not suggest struct literal when fields are private

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1449,6 +1449,34 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                         ),
                         _ => (": val", "literal", Applicability::HasPlaceholders, None),
                     };
+
+                    let fields = match def_id.as_local() {
+                        Some(def_id) => {
+                            self.r.struct_constructors.get(&def_id).cloned().map(|(_, _, f)| f)
+                        }
+                        None => Some(
+                            self.r
+                                .tcx
+                                .associated_item_def_ids(def_id)
+                                .iter()
+                                .map(|field_id| self.r.tcx.visibility(field_id))
+                                .collect(),
+                        ),
+                    };
+
+                    let hidden_fields = fields.map_or(false, |fields| {
+                        fields
+                            .iter()
+                            .filter(|vis| {
+                                !self.r.is_accessible_from(**vis, self.parent_scope.module)
+                            })
+                            .next()
+                            .is_some()
+                    });
+
+                    if !hidden_fields {
+                        // If the fields of the type are private, we shouldn't be suggesting using
+                        // the struct literal syntax at all, as that will cause a subsequent error.
                         let field_ids = self.r.field_def_ids(def_id);
                         let (fields, applicability) = match field_ids {
                             Some(field_ids) => {
@@ -1488,6 +1516,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                             applicability,
                         );
                     }
+                }
                 _ => {
                     err.span_label(span, fallback_label.to_string());
                 }

tests/ui/xcrate/xcrate-unit-struct.stderr

@@ -13,7 +13,7 @@ error[E0423]: expected value, found struct `xcrate_unit_struct::StructWithPrivFi
   --> $DIR/xcrate-unit-struct.rs:11:13
    |
 LL |     let _ = xcrate_unit_struct::StructWithPrivFields;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use struct literal syntax instead: `xcrate_unit_struct::StructWithPrivFields { foo: val }`
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
   ::: $DIR/auxiliary/xcrate_unit_struct.rs:25:1
    |