diff --git a/clippy_dev/src/lib.rs b/clippy_dev/src/lib.rs
index 83f60f15906f..1f8510f43a61 100644
--- a/clippy_dev/src/lib.rs
+++ b/clippy_dev/src/lib.rs
@@ -62,110 +62,89 @@ impl Lint {
     }
 
     /// Returns all non-deprecated lints and non-internal lints
-    pub fn usable_lints(lints: impl Iterator<Item = Self>) -> impl Iterator<Item = Self> {
-        lints.filter(|l| l.deprecation.is_none() && !l.is_internal())
+    #[must_use]
+    pub fn usable_lints(lints: &[Self]) -> Vec<Self> {
+        lints
+            .iter()
+            .filter(|l| l.deprecation.is_none() && !l.group.starts_with("internal"))
+            .cloned()
+            .collect()
     }
 
     /// Returns all internal lints (not `internal_warn` lints)
-    pub fn internal_lints(lints: impl Iterator<Item = Self>) -> impl Iterator<Item = Self> {
-        lints.filter(|l| l.group == "internal")
+    #[must_use]
+    pub fn internal_lints(lints: &[Self]) -> Vec<Self> {
+        lints.iter().filter(|l| l.group == "internal").cloned().collect()
     }
 
-    /// Returns the lints in a `HashMap`, grouped by the different lint groups
+    /// Returns all deprecated lints
     #[must_use]
-    pub fn by_lint_group(lints: impl Iterator<Item = Self>) -> HashMap<String, Vec<Self>> {
-        lints.map(|lint| (lint.group.to_string(), lint)).into_group_map()
+    pub fn deprecated_lints(lints: &[Self]) -> Vec<Self> {
+        lints.iter().filter(|l| l.deprecation.is_some()).cloned().collect()
     }
 
+    /// Returns the lints in a `HashMap`, grouped by the different lint groups
     #[must_use]
-    pub fn is_internal(&self) -> bool {
-        self.group.starts_with("internal")
+    pub fn by_lint_group(lints: impl Iterator<Item = Self>) -> HashMap<String, Vec<Self>> {
+        lints.map(|lint| (lint.group.to_string(), lint)).into_group_map()
     }
 }
 
 /// Generates the Vec items for `register_lint_group` calls in `clippy_lints/src/lib.rs`.
 #[must_use]
-pub fn gen_lint_group_list(lints: Vec<Lint>) -> Vec<String> {
+pub fn gen_lint_group_list<'a>(lints: impl Iterator<Item = &'a Lint>) -> Vec<String> {
     lints
-        .into_iter()
-        .filter_map(|l| {
-            if l.deprecation.is_some() {
-                None
-            } else {
-                Some(format!("        LintId::of(&{}::{}),", l.module, l.name.to_uppercase()))
-            }
-        })
+        .map(|l| format!("        LintId::of(&{}::{}),", l.module, l.name.to_uppercase()))
         .sorted()
         .collect::<Vec<String>>()
 }
 
 /// Generates the `pub mod module_name` list in `clippy_lints/src/lib.rs`.
 #[must_use]
-pub fn gen_modules_list(lints: Vec<Lint>) -> Vec<String> {
+pub fn gen_modules_list<'a>(lints: impl Iterator<Item = &'a Lint>) -> Vec<String> {
     lints
-        .into_iter()
-        .filter_map(|l| {
-            if l.is_internal() || l.deprecation.is_some() {
-                None
-            } else {
-                Some(l.module)
-            }
-        })
+        .map(|l| &l.module)
         .unique()
-        .map(|module| format!("pub mod {};", module))
+        .map(|module| format!("mod {};", module))
         .sorted()
         .collect::<Vec<String>>()
 }
 
 /// Generates the list of lint links at the bottom of the README
 #[must_use]
-pub fn gen_changelog_lint_list(lints: Vec<Lint>) -> Vec<String> {
-    let mut lint_list_sorted: Vec<Lint> = lints;
-    lint_list_sorted.sort_by_key(|l| l.name.clone());
-    lint_list_sorted
-        .iter()
-        .filter_map(|l| {
-            if l.is_internal() {
-                None
-            } else {
-                Some(format!("[`{}`]: {}#{}", l.name, DOCS_LINK, l.name))
-            }
-        })
+pub fn gen_changelog_lint_list<'a>(lints: impl Iterator<Item = &'a Lint>) -> Vec<String> {
+    lints
+        .sorted_by_key(|l| &l.name)
+        .map(|l| format!("[`{}`]: {}#{}", l.name, DOCS_LINK, l.name))
         .collect()
 }
 
 /// Generates the `register_removed` code in `./clippy_lints/src/lib.rs`.
 #[must_use]
-pub fn gen_deprecated(lints: &[Lint]) -> Vec<String> {
+pub fn gen_deprecated<'a>(lints: impl Iterator<Item = &'a Lint>) -> Vec<String> {
     lints
-        .iter()
-        .filter_map(|l| {
-            l.clone().deprecation.map(|depr_text| {
-                vec![
-                    "    store.register_removed(".to_string(),
-                    format!("        \"clippy::{}\",", l.name),
-                    format!("        \"{}\",", depr_text),
-                    "    );".to_string(),
-                ]
-            })
+        .flat_map(|l| {
+            l.deprecation
+                .clone()
+                .map(|depr_text| {
+                    vec![
+                        "    store.register_removed(".to_string(),
+                        format!("        \"clippy::{}\",", l.name),
+                        format!("        \"{}\",", depr_text),
+                        "    );".to_string(),
+                    ]
+                })
+                .expect("only deprecated lints should be passed")
         })
-        .flatten()
         .collect::<Vec<String>>()
 }
 
 #[must_use]
-pub fn gen_register_lint_list(lints: &[Lint]) -> Vec<String> {
+pub fn gen_register_lint_list<'a>(lints: impl Iterator<Item = &'a Lint>) -> Vec<String> {
     let pre = "    store.register_lints(&[".to_string();
     let post = "    ]);".to_string();
     let mut inner = lints
-        .iter()
-        .filter_map(|l| {
-            if !l.is_internal() && l.deprecation.is_none() {
-                Some(format!("        &{}::{},", l.module, l.name.to_uppercase()))
-            } else {
-                None
-            }
-        })
+        .map(|l| format!("        &{}::{},", l.module, l.name.to_uppercase()))
         .sorted()
         .collect::<Vec<String>>();
     inner.insert(0, pre);
@@ -439,7 +418,7 @@ fn test_usable_lints() {
         None,
         "module_name",
     )];
-    assert_eq!(expected, Lint::usable_lints(lints.into_iter()).collect::<Vec<Lint>>());
+    assert_eq!(expected, Lint::usable_lints(&lints));
 }
 
 #[test]
@@ -469,13 +448,12 @@ fn test_gen_changelog_lint_list() {
     let lints = vec![
         Lint::new("should_assert_eq", "group1", "abc", None, "module_name"),
         Lint::new("should_assert_eq2", "group2", "abc", None, "module_name"),
-        Lint::new("incorrect_internal", "internal_style", "abc", None, "module_name"),
     ];
     let expected = vec![
         format!("[`should_assert_eq`]: {}#should_assert_eq", DOCS_LINK.to_string()),
         format!("[`should_assert_eq2`]: {}#should_assert_eq2", DOCS_LINK.to_string()),
     ];
-    assert_eq!(expected, gen_changelog_lint_list(lints));
+    assert_eq!(expected, gen_changelog_lint_list(lints.iter()));
 }
 
 #[test]
@@ -495,7 +473,6 @@ fn test_gen_deprecated() {
             Some("will be removed"),
             "module_name",
         ),
-        Lint::new("should_assert_eq2", "group2", "abc", None, "module_name"),
     ];
     let expected: Vec<String> = vec![
         "    store.register_removed(",
@@ -510,22 +487,24 @@ fn test_gen_deprecated() {
     .into_iter()
     .map(String::from)
     .collect();
-    assert_eq!(expected, gen_deprecated(&lints));
+    assert_eq!(expected, gen_deprecated(lints.iter()));
+}
+
+#[test]
+#[should_panic]
+fn test_gen_deprecated_fail() {
+    let lints = vec![Lint::new("should_assert_eq2", "group2", "abc", None, "module_name")];
+    let _ = gen_deprecated(lints.iter());
 }
 
 #[test]
 fn test_gen_modules_list() {
     let lints = vec![
         Lint::new("should_assert_eq", "group1", "abc", None, "module_name"),
-        Lint::new("should_assert_eq2", "group2", "abc", Some("abc"), "deprecated"),
         Lint::new("incorrect_stuff", "group3", "abc", None, "another_module"),
-        Lint::new("incorrect_internal", "internal_style", "abc", None, "module_name"),
-    ];
-    let expected = vec![
-        "pub mod another_module;".to_string(),
-        "pub mod module_name;".to_string(),
     ];
-    assert_eq!(expected, gen_modules_list(lints));
+    let expected = vec!["mod another_module;".to_string(), "mod module_name;".to_string()];
+    assert_eq!(expected, gen_modules_list(lints.iter()));
 }
 
 #[test]
@@ -533,7 +512,6 @@ fn test_gen_lint_group_list() {
     let lints = vec![
         Lint::new("abc", "group1", "abc", None, "module_name"),
         Lint::new("should_assert_eq", "group1", "abc", None, "module_name"),
-        Lint::new("should_assert_eq2", "group2", "abc", Some("abc"), "deprecated"),
         Lint::new("internal", "internal_style", "abc", None, "module_name"),
     ];
     let expected = vec![
@@ -541,5 +519,5 @@ fn test_gen_lint_group_list() {
         "        LintId::of(&module_name::INTERNAL),".to_string(),
         "        LintId::of(&module_name::SHOULD_ASSERT_EQ),".to_string(),
     ];
-    assert_eq!(expected, gen_lint_group_list(lints));
+    assert_eq!(expected, gen_lint_group_list(lints.iter()));
 }
diff --git a/clippy_dev/src/update_lints.rs b/clippy_dev/src/update_lints.rs
index d30d6f97a2f7..a9a709299426 100644
--- a/clippy_dev/src/update_lints.rs
+++ b/clippy_dev/src/update_lints.rs
@@ -14,14 +14,14 @@ pub enum UpdateMode {
 pub fn run(update_mode: UpdateMode) {
     let lint_list: Vec<Lint> = gather_all().collect();
 
-    let internal_lints = Lint::internal_lints(lint_list.clone().into_iter());
-
-    let usable_lints: Vec<Lint> = Lint::usable_lints(lint_list.clone().into_iter()).collect();
-    let usable_lint_count = round_to_fifty(usable_lints.len());
-
+    let internal_lints = Lint::internal_lints(&lint_list);
+    let deprecated_lints = Lint::deprecated_lints(&lint_list);
+    let usable_lints = Lint::usable_lints(&lint_list);
     let mut sorted_usable_lints = usable_lints.clone();
     sorted_usable_lints.sort_by_key(|lint| lint.name.clone());
 
+    let usable_lint_count = round_to_fifty(usable_lints.len());
+
     let mut file_change = replace_region_in_file(
         Path::new("src/lintlist/mod.rs"),
         "begin lint list",
@@ -61,7 +61,7 @@ pub fn run(update_mode: UpdateMode) {
         "<!-- end autogenerated links to lint list -->",
         false,
         update_mode == UpdateMode::Change,
-        || gen_changelog_lint_list(lint_list.clone()),
+        || gen_changelog_lint_list(usable_lints.iter().chain(deprecated_lints.iter())),
     )
     .changed;
 
@@ -71,7 +71,7 @@ pub fn run(update_mode: UpdateMode) {
         "end deprecated lints",
         false,
         update_mode == UpdateMode::Change,
-        || gen_deprecated(&lint_list),
+        || gen_deprecated(deprecated_lints.iter()),
     )
     .changed;
 
@@ -81,7 +81,7 @@ pub fn run(update_mode: UpdateMode) {
         "end register lints",
         false,
         update_mode == UpdateMode::Change,
-        || gen_register_lint_list(&lint_list),
+        || gen_register_lint_list(usable_lints.iter().chain(internal_lints.iter())),
     )
     .changed;
 
@@ -91,7 +91,7 @@ pub fn run(update_mode: UpdateMode) {
         "end lints modules",
         false,
         update_mode == UpdateMode::Change,
-        || gen_modules_list(lint_list.clone()),
+        || gen_modules_list(usable_lints.iter()),
     )
     .changed;
 
@@ -104,13 +104,9 @@ pub fn run(update_mode: UpdateMode) {
         update_mode == UpdateMode::Change,
         || {
             // clippy::all should only include the following lint groups:
-            let all_group_lints = usable_lints
-                .clone()
-                .into_iter()
-                .filter(|l| {
-                    l.group == "correctness" || l.group == "style" || l.group == "complexity" || l.group == "perf"
-                })
-                .collect();
+            let all_group_lints = usable_lints.iter().filter(|l| {
+                l.group == "correctness" || l.group == "style" || l.group == "complexity" || l.group == "perf"
+            });
 
             gen_lint_group_list(all_group_lints)
         },
@@ -125,7 +121,7 @@ pub fn run(update_mode: UpdateMode) {
             r#"\]\);"#,
             false,
             update_mode == UpdateMode::Change,
-            || gen_lint_group_list(lints.clone()),
+            || gen_lint_group_list(lints.iter()),
         )
         .changed;
     }
@@ -140,8 +136,8 @@ pub fn run(update_mode: UpdateMode) {
 }
 
 pub fn print_lints() {
-    let lint_list = gather_all();
-    let usable_lints: Vec<Lint> = Lint::usable_lints(lint_list).collect();
+    let lint_list: Vec<Lint> = gather_all().collect();
+    let usable_lints = Lint::usable_lints(&lint_list);
     let usable_lint_count = usable_lints.len();
     let grouped_by_lint_group = Lint::by_lint_group(usable_lints.into_iter());
 
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index dfc2a26b06b2..b24110fc1844 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -170,157 +170,157 @@ mod consts;
 mod utils;
 
 // begin lints modules, do not remove this comment, it’s used in `update_lints`
-pub mod approx_const;
-pub mod arithmetic;
-pub mod as_conversions;
-pub mod assertions_on_constants;
-pub mod assign_ops;
-pub mod atomic_ordering;
-pub mod attrs;
-pub mod bit_mask;
-pub mod blacklisted_name;
-pub mod block_in_if_condition;
-pub mod booleans;
-pub mod bytecount;
-pub mod cargo_common_metadata;
-pub mod checked_conversions;
-pub mod cognitive_complexity;
-pub mod collapsible_if;
-pub mod comparison_chain;
-pub mod copies;
-pub mod copy_iterator;
-pub mod dbg_macro;
-pub mod default_trait_access;
-pub mod derive;
-pub mod doc;
-pub mod double_comparison;
-pub mod double_parens;
-pub mod drop_bounds;
-pub mod drop_forget_ref;
-pub mod duration_subsec;
-pub mod else_if_without_else;
-pub mod empty_enum;
-pub mod entry;
-pub mod enum_clike;
-pub mod enum_variants;
-pub mod eq_op;
-pub mod erasing_op;
-pub mod escape;
-pub mod eta_reduction;
-pub mod eval_order_dependence;
-pub mod excessive_bools;
-pub mod exit;
-pub mod explicit_write;
-pub mod fallible_impl_from;
-pub mod float_literal;
-pub mod floating_point_arithmetic;
-pub mod format;
-pub mod formatting;
-pub mod functions;
-pub mod get_last_with_len;
-pub mod identity_conversion;
-pub mod identity_op;
-pub mod if_let_some_result;
-pub mod if_not_else;
-pub mod implicit_return;
-pub mod indexing_slicing;
-pub mod infinite_iter;
-pub mod inherent_impl;
-pub mod inherent_to_string;
-pub mod inline_fn_without_body;
-pub mod int_plus_one;
-pub mod integer_division;
-pub mod items_after_statements;
-pub mod large_enum_variant;
-pub mod large_stack_arrays;
-pub mod len_zero;
-pub mod let_if_seq;
-pub mod let_underscore;
-pub mod lifetimes;
-pub mod literal_representation;
-pub mod loops;
-pub mod macro_use;
-pub mod main_recursion;
-pub mod map_clone;
-pub mod map_unit_fn;
-pub mod matches;
-pub mod mem_discriminant;
-pub mod mem_forget;
-pub mod mem_replace;
-pub mod methods;
-pub mod minmax;
-pub mod misc;
-pub mod misc_early;
-pub mod missing_const_for_fn;
-pub mod missing_doc;
-pub mod missing_inline;
-pub mod modulo_arithmetic;
-pub mod multiple_crate_versions;
-pub mod mut_key;
-pub mod mut_mut;
-pub mod mut_reference;
-pub mod mutable_debug_assertion;
-pub mod mutex_atomic;
-pub mod needless_bool;
-pub mod needless_borrow;
-pub mod needless_borrowed_ref;
-pub mod needless_continue;
-pub mod needless_pass_by_value;
-pub mod needless_update;
-pub mod neg_cmp_op_on_partial_ord;
-pub mod neg_multiply;
-pub mod new_without_default;
-pub mod no_effect;
-pub mod non_copy_const;
-pub mod non_expressive_names;
-pub mod open_options;
-pub mod option_env_unwrap;
-pub mod overflow_check_conditional;
-pub mod panic_unimplemented;
-pub mod partialeq_ne_impl;
-pub mod path_buf_push_overwrite;
-pub mod precedence;
-pub mod ptr;
-pub mod ptr_offset_with_cast;
-pub mod question_mark;
-pub mod ranges;
-pub mod redundant_clone;
-pub mod redundant_field_names;
-pub mod redundant_pattern_matching;
-pub mod redundant_pub_crate;
-pub mod redundant_static_lifetimes;
-pub mod reference;
-pub mod regex;
-pub mod returns;
-pub mod serde_api;
-pub mod shadow;
-pub mod single_component_path_imports;
-pub mod slow_vector_initialization;
-pub mod strings;
-pub mod suspicious_trait_impl;
-pub mod swap;
-pub mod tabs_in_doc_comments;
-pub mod temporary_assignment;
-pub mod to_digit_is_some;
-pub mod trait_bounds;
-pub mod transmute;
-pub mod transmuting_null;
-pub mod trivially_copy_pass_by_ref;
-pub mod try_err;
-pub mod types;
-pub mod unicode;
-pub mod unnamed_address;
-pub mod unsafe_removed_from_name;
-pub mod unused_io_amount;
-pub mod unused_self;
-pub mod unwrap;
-pub mod use_self;
-pub mod vec;
-pub mod verbose_file_reads;
-pub mod wildcard_dependencies;
-pub mod wildcard_imports;
-pub mod write;
-pub mod zero_div_zero;
+mod approx_const;
+mod arithmetic;
+mod as_conversions;
+mod assertions_on_constants;
+mod assign_ops;
+mod atomic_ordering;
+mod attrs;
+mod bit_mask;
+mod blacklisted_name;
+mod block_in_if_condition;
+mod booleans;
+mod bytecount;
+mod cargo_common_metadata;
+mod checked_conversions;
+mod cognitive_complexity;
+mod collapsible_if;
+mod comparison_chain;
+mod copies;
+mod copy_iterator;
+mod dbg_macro;
+mod default_trait_access;
+mod derive;
+mod doc;
+mod double_comparison;
+mod double_parens;
+mod drop_bounds;
+mod drop_forget_ref;
+mod duration_subsec;
+mod else_if_without_else;
+mod empty_enum;
+mod entry;
+mod enum_clike;
+mod enum_variants;
+mod eq_op;
+mod erasing_op;
+mod escape;
+mod eta_reduction;
+mod eval_order_dependence;
+mod excessive_bools;
+mod exit;
+mod explicit_write;
+mod fallible_impl_from;
+mod float_literal;
+mod floating_point_arithmetic;
+mod format;
+mod formatting;
+mod functions;
+mod get_last_with_len;
+mod identity_conversion;
+mod identity_op;
+mod if_let_some_result;
+mod if_not_else;
+mod implicit_return;
+mod indexing_slicing;
+mod infinite_iter;
+mod inherent_impl;
+mod inherent_to_string;
+mod inline_fn_without_body;
+mod int_plus_one;
+mod integer_division;
+mod items_after_statements;
+mod large_enum_variant;
+mod large_stack_arrays;
+mod len_zero;
+mod let_if_seq;
+mod let_underscore;
+mod lifetimes;
+mod literal_representation;
+mod loops;
+mod macro_use;
+mod main_recursion;
+mod map_clone;
+mod map_unit_fn;
+mod matches;
+mod mem_discriminant;
+mod mem_forget;
+mod mem_replace;
+mod methods;
+mod minmax;
+mod misc;
+mod misc_early;
+mod missing_const_for_fn;
+mod missing_doc;
+mod missing_inline;
+mod modulo_arithmetic;
+mod multiple_crate_versions;
+mod mut_key;
+mod mut_mut;
+mod mut_reference;
+mod mutable_debug_assertion;
+mod mutex_atomic;
+mod needless_bool;
+mod needless_borrow;
+mod needless_borrowed_ref;
+mod needless_continue;
+mod needless_pass_by_value;
+mod needless_update;
+mod neg_cmp_op_on_partial_ord;
+mod neg_multiply;
+mod new_without_default;
+mod no_effect;
+mod non_copy_const;
+mod non_expressive_names;
+mod open_options;
+mod option_env_unwrap;
+mod overflow_check_conditional;
+mod panic_unimplemented;
+mod partialeq_ne_impl;
+mod path_buf_push_overwrite;
+mod precedence;
+mod ptr;
+mod ptr_offset_with_cast;
+mod question_mark;
+mod ranges;
+mod redundant_clone;
+mod redundant_field_names;
+mod redundant_pattern_matching;
+mod redundant_pub_crate;
+mod redundant_static_lifetimes;
+mod reference;
+mod regex;
+mod returns;
+mod serde_api;
+mod shadow;
+mod single_component_path_imports;
+mod slow_vector_initialization;
+mod strings;
+mod suspicious_trait_impl;
+mod swap;
+mod tabs_in_doc_comments;
+mod temporary_assignment;
+mod to_digit_is_some;
+mod trait_bounds;
+mod transmute;
+mod transmuting_null;
+mod trivially_copy_pass_by_ref;
+mod try_err;
+mod types;
+mod unicode;
+mod unnamed_address;
+mod unsafe_removed_from_name;
+mod unused_io_amount;
+mod unused_self;
+mod unwrap;
+mod use_self;
+mod vec;
+mod verbose_file_reads;
+mod wildcard_dependencies;
+mod wildcard_imports;
+mod write;
+mod zero_div_zero;
 // end lints modules, do not remove this comment, it’s used in `update_lints`
 
 pub use crate::utils::conf::Conf;
@@ -828,6 +828,12 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &unwrap::PANICKING_UNWRAP,
         &unwrap::UNNECESSARY_UNWRAP,
         &use_self::USE_SELF,
+        &utils::internal_lints::CLIPPY_LINTS_INTERNAL,
+        &utils::internal_lints::COMPILER_LINT_FUNCTIONS,
+        &utils::internal_lints::DEFAULT_LINT,
+        &utils::internal_lints::LINT_WITHOUT_LINT_PASS,
+        &utils::internal_lints::OUTER_EXPN_EXPN_DATA,
+        &utils::internal_lints::PRODUCE_ICE,
         &vec::USELESS_VEC,
         &verbose_file_reads::VERBOSE_FILE_READS,
         &wildcard_dependencies::WILDCARD_DEPENDENCIES,
diff --git a/clippy_lints/src/matches.rs b/clippy_lints/src/matches.rs
index 20b793f95ded..4298e62b8037 100644
--- a/clippy_lints/src/matches.rs
+++ b/clippy_lints/src/matches.rs
@@ -1197,3 +1197,40 @@ where
 
     None
 }
+
+#[test]
+fn test_overlapping() {
+    use rustc_span::source_map::DUMMY_SP;
+
+    let sp = |s, e| SpannedRange {
+        span: DUMMY_SP,
+        node: (s, e),
+    };
+
+    assert_eq!(None, overlapping::<u8>(&[]));
+    assert_eq!(None, overlapping(&[sp(1, Bound::Included(4))]));
+    assert_eq!(
+        None,
+        overlapping(&[sp(1, Bound::Included(4)), sp(5, Bound::Included(6))])
+    );
+    assert_eq!(
+        None,
+        overlapping(&[
+            sp(1, Bound::Included(4)),
+            sp(5, Bound::Included(6)),
+            sp(10, Bound::Included(11))
+        ],)
+    );
+    assert_eq!(
+        Some((&sp(1, Bound::Included(4)), &sp(3, Bound::Included(6)))),
+        overlapping(&[sp(1, Bound::Included(4)), sp(3, Bound::Included(6))])
+    );
+    assert_eq!(
+        Some((&sp(5, Bound::Included(6)), &sp(6, Bound::Included(11)))),
+        overlapping(&[
+            sp(1, Bound::Included(4)),
+            sp(5, Bound::Included(6)),
+            sp(6, Bound::Included(11))
+        ],)
+    );
+}
diff --git a/tests/matches.rs b/tests/matches.rs
deleted file mode 100644
index 6691c074caf9..000000000000
--- a/tests/matches.rs
+++ /dev/null
@@ -1,42 +0,0 @@
-#![feature(rustc_private)]
-
-extern crate rustc_span;
-use std::collections::Bound;
-
-#[test]
-fn test_overlapping() {
-    use clippy_lints::matches::overlapping;
-    use rustc_span::source_map::DUMMY_SP;
-
-    let sp = |s, e| clippy_lints::matches::SpannedRange {
-        span: DUMMY_SP,
-        node: (s, e),
-    };
-
-    assert_eq!(None, overlapping::<u8>(&[]));
-    assert_eq!(None, overlapping(&[sp(1, Bound::Included(4))]));
-    assert_eq!(
-        None,
-        overlapping(&[sp(1, Bound::Included(4)), sp(5, Bound::Included(6))])
-    );
-    assert_eq!(
-        None,
-        overlapping(&[
-            sp(1, Bound::Included(4)),
-            sp(5, Bound::Included(6)),
-            sp(10, Bound::Included(11))
-        ],)
-    );
-    assert_eq!(
-        Some((&sp(1, Bound::Included(4)), &sp(3, Bound::Included(6)))),
-        overlapping(&[sp(1, Bound::Included(4)), sp(3, Bound::Included(6))])
-    );
-    assert_eq!(
-        Some((&sp(5, Bound::Included(6)), &sp(6, Bound::Included(11)))),
-        overlapping(&[
-            sp(1, Bound::Included(4)),
-            sp(5, Bound::Included(6)),
-            sp(6, Bound::Included(11))
-        ],)
-    );
-}