Move option_option to its own module

Author: Y-Nak

clippy_lints/src/types/mod.rs

@@ -1,6 +1,7 @@
 #![allow(rustc::default_hash_types)]
 
 mod box_vec;
+mod option_option;
 mod rc_buffer;
 mod redundant_allocation;
 mod utils;
@@ -327,19 +328,9 @@ impl Types {
                     triggered |= redundant_allocation::check(cx, hir_ty, qpath, def_id);
                     triggered |= rc_buffer::check(cx, hir_ty, qpath, def_id);
                     triggered |= vec_box::check(cx, hir_ty, qpath, def_id, self.vec_box_size_threshold);
+                    triggered |= option_option::check(cx, hir_ty, qpath, def_id);
 
-                    if cx.tcx.is_diagnostic_item(sym::option_type, def_id) {
-                        if is_ty_param_diagnostic_item(cx, qpath, sym::option_type).is_some() {
-                            span_lint(
-                                cx,
-                                OPTION_OPTION,
-                                hir_ty.span,
-                                "consider using `Option<T>` instead of `Option<Option<T>>` or a custom \
-                                 enum if you need to distinguish all 3 cases",
-                            );
-                            return; // don't recurse into the type
-                        }
-                    } else if match_def_path(cx, def_id, &paths::LINKED_LIST) {
+                    if match_def_path(cx, def_id, &paths::LINKED_LIST) {
                         span_lint_and_help(
                             cx,
                             LINKEDLIST,

clippy_lints/src/types/option_option.rs

@@ -0,0 +1,23 @@
+use rustc_hir::{self as hir, def_id::DefId, QPath};
+use rustc_lint::LateContext;
+use rustc_span::symbol::sym;
+
+use crate::utils::span_lint;
+
+use super::utils;
+
+pub(super) fn check(cx: &LateContext<'_>, hir_ty: &hir::Ty<'_>, qpath: &QPath<'_>, def_id: DefId) -> bool {
+    if cx.tcx.is_diagnostic_item(sym::option_type, def_id) {
+        if utils::is_ty_param_diagnostic_item(cx, qpath, sym::option_type).is_some() {
+            span_lint(
+                cx,
+                super::OPTION_OPTION,
+                hir_ty.span,
+                "consider using `Option<T>` instead of `Option<Option<T>>` or a custom \
+                                 enum if you need to distinguish all 3 cases",
+            );
+            return true;
+        }
+    }
+    false
+}