Check config options in test suite (#15397)

Check that all configuration options reference existing lints. This was
prompted by a discussion on a PR review in which a non-detected
discrepancy was introduced.

While adding and testing this test, references to two non-existing lints
were removed.

This test doesn't run as part of the rustc test suite.

changelog: none

Author: flip1995

book/src/lint_configuration.md

@@ -873,15 +873,13 @@ The minimum rust version that the project supports. Defaults to the `rust-versio
 * [`needless_borrow`](https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow)
 * [`non_std_lazy_statics`](https://rust-lang.github.io/rust-clippy/master/index.html#non_std_lazy_statics)
 * [`option_as_ref_deref`](https://rust-lang.github.io/rust-clippy/master/index.html#option_as_ref_deref)
-* [`option_map_unwrap_or`](https://rust-lang.github.io/rust-clippy/master/index.html#option_map_unwrap_or)
 * [`ptr_as_ptr`](https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr)
 * [`question_mark`](https://rust-lang.github.io/rust-clippy/master/index.html#question_mark)
 * [`redundant_field_names`](https://rust-lang.github.io/rust-clippy/master/index.html#redundant_field_names)
 * [`redundant_static_lifetimes`](https://rust-lang.github.io/rust-clippy/master/index.html#redundant_static_lifetimes)
 * [`repeat_vec_with_capacity`](https://rust-lang.github.io/rust-clippy/master/index.html#repeat_vec_with_capacity)
 * [`same_item_push`](https://rust-lang.github.io/rust-clippy/master/index.html#same_item_push)
 * [`seek_from_current`](https://rust-lang.github.io/rust-clippy/master/index.html#seek_from_current)
-* [`seek_rewind`](https://rust-lang.github.io/rust-clippy/master/index.html#seek_rewind)
 * [`to_digit_is_some`](https://rust-lang.github.io/rust-clippy/master/index.html#to_digit_is_some)
 * [`transmute_ptr_to_ref`](https://rust-lang.github.io/rust-clippy/master/index.html#transmute_ptr_to_ref)
 * [`tuple_array_conversions`](https://rust-lang.github.io/rust-clippy/master/index.html#tuple_array_conversions)

clippy_config/src/conf.rs

@@ -775,15 +775,13 @@ define_Conf! {
         needless_borrow,
         non_std_lazy_statics,
         option_as_ref_deref,
-        option_map_unwrap_or,
         ptr_as_ptr,
         question_mark,
         redundant_field_names,
         redundant_static_lifetimes,
         repeat_vec_with_capacity,
         same_item_push,
         seek_from_current,
-        seek_rewind,
         to_digit_is_some,
         transmute_ptr_to_ref,
         tuple_array_conversions,

tests/config-consistency.rs

@@ -0,0 +1,30 @@
+#![feature(rustc_private)]
+
+// This test checks that all lints defined in `clippy_config::conf` in `#[lints]`
+// attributes exist as Clippy lints.
+//
+// This test is a no-op if run as part of the compiler test suite
+// and will always succeed.
+
+use std::collections::HashSet;
+
+#[test]
+fn config_consistency() {
+    if option_env!("RUSTC_TEST_SUITE").is_some() {
+        return;
+    }
+
+    let lint_names: HashSet<String> = clippy_lints::declared_lints::LINTS
+        .iter()
+        .map(|lint_info| lint_info.lint.name.strip_prefix("clippy::").unwrap().to_lowercase())
+        .collect();
+    for conf in clippy_config::get_configuration_metadata() {
+        for lint in conf.lints {
+            assert!(
+                lint_names.contains(*lint),
+                "Configuration option {} references lint `{lint}` which does not exist",
+                conf.name
+            );
+        }
+    }
+}