[Clippy] Swap repeat_vec_with_capacity to use diagnostic item instead of path

Author: GnomedDev

compiler/rustc_span/src/symbol.rs

@@ -2094,6 +2094,7 @@ symbols! {
         vec_from_elem,
         vec_macro,
         vec_new,
+        vec_with_capacity,
         vecdeque_iter,
         version,
         vfp2,

library/alloc/src/vec/mod.rs

@@ -477,6 +477,7 @@ impl<T> Vec<T> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "vec_with_capacity")]
     pub fn with_capacity(capacity: usize) -> Self {
         Self::with_capacity_in(capacity, Global)
     }

src/tools/clippy/clippy_lints/src/repeat_vec_with_capacity.rs

@@ -3,7 +3,7 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::higher::VecArgs;
 use clippy_utils::macros::matching_root_macro_call;
 use clippy_utils::source::snippet;
-use clippy_utils::{expr_or_init, fn_def_id, match_def_path, paths};
+use clippy_utils::{expr_or_init, fn_def_id};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -67,7 +67,7 @@ fn emit_lint(cx: &LateContext<'_>, span: Span, kind: &str, note: &'static str, s
 fn check_vec_macro(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if matching_root_macro_call(cx, expr.span, sym::vec_macro).is_some()
         && let Some(VecArgs::Repeat(repeat_expr, len_expr)) = VecArgs::hir(cx, expr)
-        && fn_def_id(cx, repeat_expr).is_some_and(|did| match_def_path(cx, did, &paths::VEC_WITH_CAPACITY))
+        && fn_def_id(cx, repeat_expr).is_some_and(|did| cx.tcx.is_diagnostic_item(sym::vec_with_capacity, did))
         && !len_expr.span.from_expansion()
         && let Some(Constant::Int(2..)) = ConstEvalCtxt::new(cx).eval(expr_or_init(cx, len_expr))
     {
@@ -91,7 +91,7 @@ fn check_repeat_fn(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if !expr.span.from_expansion()
         && fn_def_id(cx, expr).is_some_and(|did| cx.tcx.is_diagnostic_item(sym::iter_repeat, did))
         && let ExprKind::Call(_, [repeat_expr]) = expr.kind
-        && fn_def_id(cx, repeat_expr).is_some_and(|did| match_def_path(cx, did, &paths::VEC_WITH_CAPACITY))
+        && fn_def_id(cx, repeat_expr).is_some_and(|did| cx.tcx.is_diagnostic_item(sym::vec_with_capacity, did))
         && !repeat_expr.span.from_expansion()
     {
         emit_lint(

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

@@ -2,8 +2,8 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::macros::matching_root_macro_call;
 use clippy_utils::sugg::Sugg;
 use clippy_utils::{
-    get_enclosing_block, is_expr_path_def_path, is_integer_literal, is_path_diagnostic_item, path_to_local,
-    path_to_local_id, paths, SpanlessEq,
+    get_enclosing_block, is_integer_literal, is_path_diagnostic_item, path_to_local,
+    path_to_local_id, SpanlessEq,
 };
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_block, walk_expr, walk_stmt, Visitor};
@@ -150,7 +150,7 @@ impl SlowVectorInit {
         }
 
         if let ExprKind::Call(func, [len_expr]) = expr.kind
-            && is_expr_path_def_path(cx, func, &paths::VEC_WITH_CAPACITY)
+            && is_path_diagnostic_item(cx, func, sym::vec_with_capacity)
         {
             Some(InitializedSize::Initialized(len_expr))
         } else if matches!(expr.kind, ExprKind::Call(func, _) if is_path_diagnostic_item(cx, func, sym::vec_new)) {

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

@@ -72,7 +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_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"];
 pub const VEC_POP: [&str; 4] = ["alloc", "vec", "Vec", "pop"];