From ece7fa4f9c4e934a3176de9abcf9ab3b71a6dd7c Mon Sep 17 00:00:00 2001
From: Cameron Steffen <cam.steffen94@gmail.com>
Date: Thu, 6 Jan 2022 09:39:46 -0600
Subject: [PATCH] Factor out match_any_diagnostic_items

---
 clippy_lints/src/ptr.rs                       |  5 +---
 .../transmute/unsound_collection_transmute.rs | 30 ++++++++++---------
 clippy_utils/src/lib.rs                       | 10 +------
 3 files changed, 18 insertions(+), 27 deletions(-)

diff --git a/clippy_lints/src/ptr.rs b/clippy_lints/src/ptr.rs
index 26717c0c0fd..6decd18b0a3 100644
--- a/clippy_lints/src/ptr.rs
+++ b/clippy_lints/src/ptr.rs
@@ -3,10 +3,7 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::expr_sig;
-use clippy_utils::{
-    expr_path_res, get_expr_use_or_unification_node, is_lint_allowed, is_lint_allowed, match_any_diagnostic_items,
-    path_def_id, path_to_local, paths, paths,
-};
+use clippy_utils::{get_expr_use_or_unification_node, is_lint_allowed, path_def_id, path_to_local, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
diff --git a/clippy_lints/src/transmute/unsound_collection_transmute.rs b/clippy_lints/src/transmute/unsound_collection_transmute.rs
index 2ce8d4031d7..2d67401a15f 100644
--- a/clippy_lints/src/transmute/unsound_collection_transmute.rs
+++ b/clippy_lints/src/transmute/unsound_collection_transmute.rs
@@ -1,29 +1,31 @@
 use super::utils::is_layout_incompatible;
 use super::UNSOUND_COLLECTION_TRANSMUTE;
 use clippy_utils::diagnostics::span_lint;
-use clippy_utils::match_any_diagnostic_items;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty};
-use rustc_span::symbol::{sym, Symbol};
-
-// used to check for UNSOUND_COLLECTION_TRANSMUTE
-static COLLECTIONS: &[Symbol] = &[
-    sym::Vec,
-    sym::VecDeque,
-    sym::BinaryHeap,
-    sym::BTreeSet,
-    sym::BTreeMap,
-    sym::HashSet,
-    sym::HashMap,
-];
+use rustc_span::symbol::sym;
 
 /// Checks for `unsound_collection_transmute` lint.
 /// Returns `true` if it's triggered, otherwise returns `false`.
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) -> bool {
     match (&from_ty.kind(), &to_ty.kind()) {
         (ty::Adt(from_adt, from_substs), ty::Adt(to_adt, to_substs)) => {
-            if from_adt.did != to_adt.did || match_any_diagnostic_items(cx, to_adt.did, COLLECTIONS).is_none() {
+            if from_adt.did != to_adt.did {
+                return false;
+            }
+            if !matches!(
+                cx.tcx.get_diagnostic_name(to_adt.did),
+                Some(
+                    sym::BTreeMap
+                        | sym::BTreeSet
+                        | sym::BinaryHeap
+                        | sym::HashMap
+                        | sym::HashSet
+                        | sym::Vec
+                        | sym::VecDeque
+                )
+            ) {
                 return false;
             }
             if from_substs
diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index eeadc6d4dda..62066987232 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -1615,7 +1615,7 @@ pub fn match_function_call<'tcx>(
 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
 /// any.
 ///
-/// Please use `match_any_diagnostic_items` if the targets are all diagnostic items.
+/// Please use `tcx.get_diagnostic_name` if the targets are all diagnostic items.
 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
     let search_path = cx.get_def_path(did);
     paths
@@ -1623,14 +1623,6 @@ pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]])
         .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
 }
 
-/// Checks if the given `DefId` matches any of provided diagnostic items. Returns the index of
-/// matching path, if any.
-pub fn match_any_diagnostic_items(cx: &LateContext<'_>, def_id: DefId, diag_items: &[Symbol]) -> Option<usize> {
-    diag_items
-        .iter()
-        .position(|item| cx.tcx.is_diagnostic_item(*item, def_id))
-}
-
 /// Checks if the given `DefId` matches the path.
 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
     // We should probably move to Symbols in Clippy as well rather than interning every time.