Fix flat_map_option lint

Author: nyurik

Cargo.toml

@@ -59,7 +59,6 @@ cast_precision_loss = "allow"
 cast_sign_loss = "allow"
 default_trait_access = "allow"
 explicit_into_iter_loop = "allow"
-flat_map_option = "allow"
 ignored_unit_patterns = "allow"
 implicit_hasher = "allow"
 items_after_statements = "allow"

bindgen/codegen/mod.rs

@@ -2630,12 +2630,9 @@ impl CodeGenerator for CompInfo {
                     } else {
                         self.fields()
                             .iter()
-                            .filter_map(|field| match *field {
-                                Field::DataMember(ref f) if f.name().is_some() => Some(f),
-                                _ => None,
-                            })
-                            .flat_map(|field| {
-                                let name = field.name().unwrap();
+                            .filter_map(|field| {
+                                let Field::DataMember(field) = field else { return None };
+                                let name = field.name()?;
                                 field.offset().map(|offset| {
                                     let field_offset = offset / 8;
                                     let field_name = ctx.rust_ident(name);