From 7984e60d9e1ee36b943cc72e4e7b33d05e6ee83d Mon Sep 17 00:00:00 2001
From: Cameron Steffen <cam.steffen94@gmail.com>
Date: Fri, 26 Feb 2021 21:17:29 -0600
Subject: [PATCH] Use diagnostic items in into_iter_collections

---
 clippy_lints/src/methods/mod.rs |  4 ++--
 clippy_utils/src/lib.rs         | 40 ++++++++++++++++-----------------
 clippy_utils/src/paths.rs       |  2 --
 3 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs
index f101b6476f5..5163074453b 100644
--- a/clippy_lints/src/methods/mod.rs
+++ b/clippy_lints/src/methods/mod.rs
@@ -24,7 +24,7 @@
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
-use rustc_span::symbol::{sym, SymbolStr};
+use rustc_span::symbol::{sym, Symbol, SymbolStr};
 use rustc_typeck::hir_ty_to_ty;
 
 use crate::consts::{constant, Constant};
@@ -3619,7 +3619,7 @@ fn lint_asref(cx: &LateContext<'_>, expr: &hir::Expr<'_>, call_name: &str, as_re
     }
 }
 
-fn ty_has_iter_method(cx: &LateContext<'_>, self_ref_ty: Ty<'_>) -> Option<(&'static str, &'static str)> {
+fn ty_has_iter_method(cx: &LateContext<'_>, self_ref_ty: Ty<'_>) -> Option<(Symbol, &'static str)> {
     has_iter_method(cx, self_ref_ty).map(|ty_name| {
         let mutbl = match self_ref_ty.kind() {
             ty::Ref(_, _, mutbl) => mutbl,
diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index 94b7339c7eb..42512cadfb1 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -1295,24 +1295,24 @@ pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool
 }
 
 /// Returns true if ty has `iter` or `iter_mut` methods
-pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
+pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<Symbol> {
     // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
     // exists and has the desired signature. Unfortunately FnCtxt is not exported
     // so we can't use its `lookup_method` method.
-    let into_iter_collections: [&[&str]; 13] = [
-        &paths::VEC,
-        &paths::OPTION,
-        &paths::RESULT,
-        &paths::BTREESET,
-        &paths::BTREEMAP,
-        &paths::VEC_DEQUE,
-        &paths::LINKED_LIST,
-        &paths::BINARY_HEAP,
-        &paths::HASHSET,
-        &paths::HASHMAP,
-        &paths::PATH_BUF,
-        &paths::PATH,
-        &paths::RECEIVER,
+    let into_iter_collections: &[Symbol] = &[
+        sym::vec_type,
+        sym::option_type,
+        sym::result_type,
+        sym::BTreeMap,
+        sym::BTreeSet,
+        sym::vecdeque_type,
+        sym::LinkedList,
+        sym::BinaryHeap,
+        sym::hashset_type,
+        sym::hashmap_type,
+        sym::PathBuf,
+        sym::Path,
+        sym::Receiver,
     ];
 
     let ty_to_check = match probably_ref_ty.kind() {
@@ -1321,15 +1321,15 @@ pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<
     };
 
     let def_id = match ty_to_check.kind() {
-        ty::Array(..) => return Some("array"),
-        ty::Slice(..) => return Some("slice"),
+        ty::Array(..) => return Some(sym::array),
+        ty::Slice(..) => return Some(sym::slice),
         ty::Adt(adt, _) => adt.did,
         _ => return None,
     };
 
-    for path in &into_iter_collections {
-        if match_def_path(cx, def_id, path) {
-            return Some(*path.last().unwrap());
+    for &name in into_iter_collections {
+        if cx.tcx.is_diagnostic_item(name, def_id) {
+            return Some(cx.tcx.item_name(def_id));
         }
     }
     None
diff --git a/clippy_utils/src/paths.rs b/clippy_utils/src/paths.rs
index e6178679647..c2da1f9b7c9 100644
--- a/clippy_utils/src/paths.rs
+++ b/clippy_utils/src/paths.rs
@@ -99,7 +99,6 @@
 pub const PARKING_LOT_MUTEX_GUARD: [&str; 2] = ["parking_lot", "MutexGuard"];
 pub const PARKING_LOT_RWLOCK_READ_GUARD: [&str; 2] = ["parking_lot", "RwLockReadGuard"];
 pub const PARKING_LOT_RWLOCK_WRITE_GUARD: [&str; 2] = ["parking_lot", "RwLockWriteGuard"];
-pub const PATH: [&str; 3] = ["std", "path", "Path"];
 pub const PATH_BUF: [&str; 3] = ["std", "path", "PathBuf"];
 pub const PATH_BUF_AS_PATH: [&str; 4] = ["std", "path", "PathBuf", "as_path"];
 pub const PATH_TO_PATH_BUF: [&str; 4] = ["std", "path", "Path", "to_path_buf"];
@@ -116,7 +115,6 @@
 pub const RANGE_ARGUMENT_TRAIT: [&str; 3] = ["core", "ops", "RangeBounds"];
 pub const RC: [&str; 3] = ["alloc", "rc", "Rc"];
 pub const RC_PTR_EQ: [&str; 4] = ["alloc", "rc", "Rc", "ptr_eq"];
-pub const RECEIVER: [&str; 4] = ["std", "sync", "mpsc", "Receiver"];
 pub const REFCELL_REF: [&str; 3] = ["core", "cell", "Ref"];
 pub const REFCELL_REFMUT: [&str; 3] = ["core", "cell", "RefMut"];
 pub const REGEX_BUILDER_NEW: [&str; 5] = ["regex", "re_builder", "unicode", "RegexBuilder", "new"];