1 use rustc::hir::{Crate, Expr, ExprKind, QPath};
2 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
3 use rustc::{declare_tool_lint, impl_lint_pass};
4 use syntax::ast::AttrKind;
5 use syntax::symbol::sym;
7 use crate::utils::{is_entrypoint_fn, snippet, span_help_and_lint};
8 use if_chain::if_chain;
10 declare_clippy_lint! {
11 /// **What it does:** Checks for recursion using the entrypoint.
13 /// **Why is this bad?** Apart from special setups (which we could detect following attributes like #![no_std]),
14 /// recursing into main() seems like an unintuitive antipattern we should be able to detect.
16 /// **Known problems:** None.
26 "recursion using the entrypoint"
30 pub struct MainRecursion {
31 has_no_std_attr: bool,
34 impl_lint_pass!(MainRecursion => [MAIN_RECURSION]);
36 impl LateLintPass<'_, '_> for MainRecursion {
37 fn check_crate(&mut self, _: &LateContext<'_, '_>, krate: &Crate) {
38 self.has_no_std_attr = krate.attrs.iter().any(|attr| {
39 if let AttrKind::Normal(ref attr) = attr.kind {
40 attr.path == sym::no_std
47 fn check_expr_post(&mut self, cx: &LateContext<'_, '_>, expr: &Expr) {
48 if self.has_no_std_attr {
53 if let ExprKind::Call(func, _) = &expr.kind;
54 if let ExprKind::Path(path) = &func.kind;
55 if let QPath::Resolved(_, path) = &path;
56 if let Some(def_id) = path.res.opt_def_id();
57 if is_entrypoint_fn(cx, def_id);
63 &format!("recursing into entrypoint `{}`", snippet(cx, func.span, "main")),
64 "consider using another function for this recursion"