1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
use clippy_utils::diagnostics::span_lint_and_help;
use clippy_utils::source::snippet;
use clippy_utils::{is_entrypoint_fn, is_no_std_crate};
use rustc_hir::{Expr, ExprKind, QPath};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::impl_lint_pass;
declare_clippy_lint! {
/// ### What it does
/// Checks for recursion using the entrypoint.
///
/// ### Why is this bad?
/// Apart from special setups (which we could detect following attributes like #![no_std]),
/// recursing into main() seems like an unintuitive anti-pattern we should be able to detect.
///
/// ### Example
/// ```no_run
/// fn main() {
/// main();
/// }
/// ```
#[clippy::version = "1.38.0"]
pub MAIN_RECURSION,
style,
"recursion using the entrypoint"
}
#[derive(Default)]
pub struct MainRecursion {
has_no_std_attr: bool,
}
impl_lint_pass!(MainRecursion => [MAIN_RECURSION]);
impl LateLintPass<'_> for MainRecursion {
fn check_crate(&mut self, cx: &LateContext<'_>) {
self.has_no_std_attr = is_no_std_crate(cx);
}
fn check_expr_post(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
if self.has_no_std_attr {
return;
}
if let ExprKind::Call(func, []) = &expr.kind
&& let ExprKind::Path(QPath::Resolved(_, path)) = &func.kind
&& let Some(def_id) = path.res.opt_def_id()
&& is_entrypoint_fn(cx, def_id)
{
span_lint_and_help(
cx,
MAIN_RECURSION,
func.span,
format!("recursing into entrypoint `{}`", snippet(cx, func.span, "main")),
None,
"consider using another function for this recursion",
);
}
}
}
|
