Auto merge of rust-lang#8783 - flip1995:ouir-nursery, r=llogiq

Move only_used_in_recursion to nursery

r? `@llogiq`

I still think this is the right thing to do for this lint. See: rust-lang#8782

I want to get this merged before the sync on Thursday, because I want to backport this and the last fix rust-lang#8691 to beta.

changelog: Move [`only_used_in_recursion`] to nursery

Author: bors

clippy_lints/src/lib.register_all.rs

@@ -248,7 +248,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(non_expressive_names::JUST_UNDERSCORES_AND_DIGITS),
     LintId::of(non_octal_unix_permissions::NON_OCTAL_UNIX_PERMISSIONS),
     LintId::of(octal_escapes::OCTAL_ESCAPES),
-    LintId::of(only_used_in_recursion::ONLY_USED_IN_RECURSION),
     LintId::of(open_options::NONSENSICAL_OPEN_OPTIONS),
     LintId::of(option_env_unwrap::OPTION_ENV_UNWRAP),
     LintId::of(overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL),

clippy_lints/src/lib.register_complexity.rs

@@ -68,7 +68,6 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(neg_cmp_op_on_partial_ord::NEG_CMP_OP_ON_PARTIAL_ORD),
     LintId::of(no_effect::NO_EFFECT),
     LintId::of(no_effect::UNNECESSARY_OPERATION),
-    LintId::of(only_used_in_recursion::ONLY_USED_IN_RECURSION),
     LintId::of(overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL),
     LintId::of(partialeq_ne_impl::PARTIALEQ_NE_IMPL),
     LintId::of(precedence::PRECEDENCE),

clippy_lints/src/lib.register_nursery.rs

@@ -20,6 +20,7 @@ store.register_group(true, "clippy::nursery", Some("clippy_nursery"), vec![
     LintId::of(mutex_atomic::MUTEX_INTEGER),
     LintId::of(non_send_fields_in_send_ty::NON_SEND_FIELDS_IN_SEND_TY),
     LintId::of(nonstandard_macro_braces::NONSTANDARD_MACRO_BRACES),
+    LintId::of(only_used_in_recursion::ONLY_USED_IN_RECURSION),
     LintId::of(option_if_let_else::OPTION_IF_LET_ELSE),
     LintId::of(path_buf_push_overwrite::PATH_BUF_PUSH_OVERWRITE),
     LintId::of(redundant_pub_crate::REDUNDANT_PUB_CRATE),

clippy_lints/src/only_used_in_recursion.rs

@@ -1,6 +1,7 @@
 use std::collections::VecDeque;
 
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_lint_allowed;
 use itertools::{izip, Itertools};
 use rustc_ast::{walk_list, Label, Mutability};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -33,6 +34,9 @@ declare_clippy_lint! {
     /// and the assigned variables are also only in recursion, it is useless.
     ///
     /// ### Known problems
+    /// Too many code paths in the linting code are currently untested and prone to produce false
+    /// positives or are prone to have performance implications.
+    ///
     /// In some cases, this would not catch all useless arguments.
     ///
     /// ```rust
@@ -85,7 +89,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.60.0"]
     pub ONLY_USED_IN_RECURSION,
-    complexity,
+    nursery,
     "arguments that is only used in recursion can be removed"
 }
 declare_lint_pass!(OnlyUsedInRecursion => [ONLY_USED_IN_RECURSION]);
@@ -100,6 +104,9 @@ impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion {
         _: Span,
         id: HirId,
     ) {
+        if is_lint_allowed(cx, ONLY_USED_IN_RECURSION, id) {
+            return;
+        }
         if let FnKind::ItemFn(ident, ..) | FnKind::Method(ident, ..) = kind {
             let def_id = id.owner.to_def_id();
             let data = cx.tcx.def_path(def_id).data;