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[slow_vector_initialization]: only warn on vec![] expn

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y21 2023-09-02 16:21:46 +02:00
parent 78983d9e3f
commit 51206323a1
3 changed files with 35 additions and 3 deletions
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10
clippy_lints/src/slow_vector_initialization.rs
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@ -1,4 +1,5 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::macros::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,
@ -148,6 +149,15 @@ impl SlowVectorInit {
/// - `Some(InitializedSize::Uninitialized)` for `Vec::new()`
/// - `None` for other, unrelated kinds of expressions
fn as_vec_initializer<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<InitializedSize<'tcx>> {
// Generally don't warn if the vec initializer comes from an expansion, except for the vec! macro.
// This lets us still warn on `vec![]`, while ignoring other kinds of macros that may output an
// empty vec
if expr.span.from_expansion()
&& root_macro_call(expr.span).map(|m| m.def_id) != cx.tcx.get_diagnostic_item(sym::vec_macro)
{
return None;
}
if let ExprKind::Call(func, [len_expr]) = expr.kind
&& is_expr_path_def_path(cx, func, &paths::VEC_WITH_CAPACITY)
{