Move assert_matches to planned stable path

clippy_utils/src/ty/mod.rs

@@ -29,7 +29,10 @@
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 use rustc_trait_selection::traits::query::normalize::QueryNormalizeExt;
 use rustc_trait_selection::traits::{Obligation, ObligationCause};
+#[cfg(bootstrap)]
 use std::assert_matches::debug_assert_matches;
+#[cfg(not(bootstrap))]
+use std::debug_assert_matches;
 use std::collections::hash_map::Entry;
 use std::{iter, mem};