[Clippy] Swap VecArgs::hir to use diagnostic items instead of paths

compiler/rustc_span/src/symbol.rs

@@ -1836,6 +1836,7 @@ symbols! {
         slice,
         slice_from_raw_parts,
         slice_from_raw_parts_mut,
+        slice_into_vec,
         slice_iter,
         slice_len_fn,
         slice_patterns,
@@ -2090,7 +2091,9 @@ symbols! {
         vec,
         vec_as_mut_slice,
         vec_as_slice,
+        vec_from_elem,
         vec_macro,
+        vec_new,
         vecdeque_iter,
         version,
         vfp2,

library/alloc/src/slice.rs

@@ -496,6 +496,7 @@ impl<T> [T] {
     #[rustc_allow_incoherent_impl]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "slice_into_vec")]
     pub fn into_vec<A: Allocator>(self: Box<Self, A>) -> Vec<T, A> {
         // N.B., see the `hack` module in this file for more details.
         hack::into_vec(self)

library/alloc/src/vec/mod.rs

@@ -416,6 +416,7 @@ impl<T> Vec<T> {
     /// ```
     #[inline]
     #[rustc_const_stable(feature = "const_vec_new", since = "1.39.0")]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "vec_new")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
     pub const fn new() -> Self {
@@ -3046,6 +3047,7 @@ impl<T: PartialEq, A: Allocator> Vec<T, A> {
 #[doc(hidden)]
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "vec_from_elem")]
 pub fn from_elem<T: Clone>(elem: T, n: usize) -> Vec<T> {
     <T as SpecFromElem>::from_elem(elem, n, Global)
 }

src/tools/clippy/clippy_lints/src/slow_vector_initialization.rs

@@ -153,7 +153,7 @@ impl SlowVectorInit {
             && is_expr_path_def_path(cx, func, &paths::VEC_WITH_CAPACITY)
         {
             Some(InitializedSize::Initialized(len_expr))
-        } else if matches!(expr.kind, ExprKind::Call(func, _) if is_expr_path_def_path(cx, func, &paths::VEC_NEW)) {
+        } else if matches!(expr.kind, ExprKind::Call(func, _) if is_path_diagnostic_item(cx, func, sym::vec_new)) {
             Some(InitializedSize::Uninitialized)
         } else {
             None

src/tools/clippy/clippy_utils/src/higher.rs

@@ -4,7 +4,7 @@
 
 use crate::consts::{ConstEvalCtxt, Constant};
 use crate::ty::is_type_diagnostic_item;
-use crate::{is_expn_of, match_def_path, paths};
+use crate::is_expn_of;
 
 use rustc_ast::ast;
 use rustc_hir as hir;
@@ -297,10 +297,10 @@ impl<'a> VecArgs<'a> {
             && is_expn_of(fun.span, "vec").is_some()
             && let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id()
         {
-            return if match_def_path(cx, fun_def_id, &paths::VEC_FROM_ELEM) && args.len() == 2 {
+            return if cx.tcx.is_diagnostic_item(sym::vec_from_elem, fun_def_id) && args.len() == 2 {
                 // `vec![elem; size]` case
                 Some(VecArgs::Repeat(&args[0], &args[1]))
-            } else if match_def_path(cx, fun_def_id, &paths::SLICE_INTO_VEC) && args.len() == 1 {
+            } else if cx.tcx.is_diagnostic_item(sym::slice_into_vec, fun_def_id) && args.len() == 1 {
                 // `vec![a, b, c]` case
                 if let ExprKind::Call(_, [arg]) = &args[0].kind
                     && let ExprKind::Array(args) = arg.kind
@@ -309,7 +309,7 @@ impl<'a> VecArgs<'a> {
                 } else {
                     None
                 }
-            } else if match_def_path(cx, fun_def_id, &paths::VEC_NEW) && args.is_empty() {
+            } else if cx.tcx.is_diagnostic_item(sym::vec_new, fun_def_id) && args.is_empty() {
                 Some(VecArgs::Vec(&[]))
             } else {
                 None

src/tools/clippy/clippy_utils/src/paths.rs

@@ -49,7 +49,6 @@ pub const REGEX_NEW: [&str; 3] = ["regex", "Regex", "new"];
 pub const REGEX_SET_NEW: [&str; 3] = ["regex", "RegexSet", "new"];
 pub const SERDE_DESERIALIZE: [&str; 3] = ["serde", "de", "Deserialize"];
 pub const SERDE_DE_VISITOR: [&str; 3] = ["serde", "de", "Visitor"];
-pub const SLICE_INTO_VEC: [&str; 4] = ["alloc", "slice", "<impl [T]>", "into_vec"];
 pub const STD_IO_SEEK_FROM_CURRENT: [&str; 4] = ["std", "io", "SeekFrom", "Current"];
 pub const STD_IO_SEEKFROM_START: [&str; 4] = ["std", "io", "SeekFrom", "Start"];
 pub const STRING_NEW: [&str; 4] = ["alloc", "string", "String", "new"];
@@ -73,8 +72,6 @@ pub const TOKIO_IO_ASYNCWRITEEXT: [&str; 5] = ["tokio", "io", "util", "async_wri
 pub const TOKIO_IO_OPEN_OPTIONS: [&str; 4] = ["tokio", "fs", "open_options", "OpenOptions"];
 #[expect(clippy::invalid_paths)] // internal lints do not know about all external crates
 pub const TOKIO_IO_OPEN_OPTIONS_NEW: [&str; 5] = ["tokio", "fs", "open_options", "OpenOptions", "new"];
-pub const VEC_FROM_ELEM: [&str; 3] = ["alloc", "vec", "from_elem"];
-pub const VEC_NEW: [&str; 4] = ["alloc", "vec", "Vec", "new"];
 pub const VEC_WITH_CAPACITY: [&str; 4] = ["alloc", "vec", "Vec", "with_capacity"];
 pub const INSTANT_NOW: [&str; 4] = ["std", "time", "Instant", "now"];
 pub const VEC_IS_EMPTY: [&str; 4] = ["alloc", "vec", "Vec", "is_empty"];