Use diagnostic items for `Into`, `IntoIterator`, `LinkedList`, `ptr::null`, `prt::null_mut`

2 files changed, 22 insertions, 4 deletions

diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index 364ae536ecd..b19d1430b6e 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -411,12 +411,22 @@ pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId,
 }
 
 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
+///
+/// Please use `is_expr_diagnostic_item` if the target is a diagnostic item.
 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
     expr_path_res(cx, expr)
         .opt_def_id()
         .map_or(false, |id| match_def_path(cx, id, segments))
 }
 
+/// If the expression is a path, resolves it to a `DefId` and checks if it matches the given
+/// diagnostic item.
+pub fn is_expr_diagnostic_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
+    expr_path_res(cx, expr)
+        .opt_def_id()
+        .map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
+}
+
 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
 /// `QPath::Resolved.1.res.opt_def_id()`.
@@ -1249,6 +1259,8 @@ 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.
 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
     let search_path = cx.get_def_path(did);
     paths
@@ -1256,6 +1268,14 @@ 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.
diff --git a/clippy_utils/src/paths.rs b/clippy_utils/src/paths.rs
index 3acde01b8c9..e9e371e3e3e 100644
--- a/clippy_utils/src/paths.rs
+++ b/clippy_utils/src/paths.rs
@@ -73,8 +73,6 @@ pub const IDENT_AS_STR: [&str; 4] = ["rustc_span", "symbol", "Ident", "as_str"];
 pub const INDEX: [&str; 3] = ["core", "ops", "Index"];
 pub const INDEX_MUT: [&str; 3] = ["core", "ops", "IndexMut"];
 pub const INSERT_STR: [&str; 4] = ["alloc", "string", "String", "insert_str"];
-pub const INTO: [&str; 3] = ["core", "convert", "Into"];
-pub const INTO_ITERATOR: [&str; 5] = ["core", "iter", "traits", "collect", "IntoIterator"];
 pub const IO_READ: [&str; 3] = ["std", "io", "Read"];
 pub const IO_WRITE: [&str; 3] = ["std", "io", "Write"];
 pub const IPADDR_V4: [&str; 5] = ["std", "net", "ip", "IpAddr", "V4"];
@@ -85,6 +83,7 @@ pub const KW_MODULE: [&str; 3] = ["rustc_span", "symbol", "kw"];
 #[cfg(feature = "internal-lints")]
 pub const LATE_CONTEXT: [&str; 2] = ["rustc_lint", "LateContext"];
 pub const LIBC_STRLEN: [&str; 2] = ["libc", "strlen"];
+/// Preferably use the diagnostic item `sym::LinkedList` where possible
 pub const LINKED_LIST: [&str; 4] = ["alloc", "collections", "linked_list", "LinkedList"];
 #[cfg(any(feature = "internal-lints", feature = "metadata-collector-lint"))]
 pub const LINT: [&str; 2] = ["rustc_lint_defs", "Lint"];
@@ -99,6 +98,7 @@ pub const MEM_SIZE_OF_VAL: [&str; 3] = ["core", "mem", "size_of_val"];
 pub const MUTEX_GUARD: [&str; 4] = ["std", "sync", "mutex", "MutexGuard"];
 pub const OPEN_OPTIONS: [&str; 3] = ["std", "fs", "OpenOptions"];
 pub const OPS_MODULE: [&str; 2] = ["core", "ops"];
+/// Preferably use the diagnostic item `sym::option_type` where possible
 pub const OPTION: [&str; 3] = ["core", "option", "Option"];
 pub const OPTION_NONE: [&str; 4] = ["core", "option", "Option", "None"];
 pub const OPTION_SOME: [&str; 4] = ["core", "option", "Option", "Some"];
@@ -122,8 +122,6 @@ pub const POLL_READY: [&str; 5] = ["core", "task", "poll", "Poll", "Ready"];
 pub const PTR_COPY: [&str; 3] = ["core", "intrinsics", "copy"];
 pub const PTR_COPY_NONOVERLAPPING: [&str; 3] = ["core", "intrinsics", "copy_nonoverlapping"];
 pub const PTR_EQ: [&str; 3] = ["core", "ptr", "eq"];
-pub const PTR_NULL: [&str; 3] = ["core", "ptr", "null"];
-pub const PTR_NULL_MUT: [&str; 3] = ["core", "ptr", "null_mut"];
 pub const PTR_SLICE_FROM_RAW_PARTS: [&str; 3] = ["core", "ptr", "slice_from_raw_parts"];
 pub const PTR_SLICE_FROM_RAW_PARTS_MUT: [&str; 3] = ["core", "ptr", "slice_from_raw_parts_mut"];
 pub const PTR_SWAP_NONOVERLAPPING: [&str; 3] = ["core", "ptr", "swap_nonoverlapping"];