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::symbol::sym;
6 use crate::utils::{is_entrypoint_fn, snippet, span_help_and_lint};
7 use if_chain::if_chain;
10 /// **What it does:** Checks for recursion using the entrypoint.
12 /// **Why is this bad?** Apart from special setups (which we could detect following attributes like #![no_std]),
13 /// recursing into main() seems like an unintuitive antipattern we should be able to detect.
15 /// **Known problems:** None.
25 "recursion using the entrypoint"
29 pub struct MainRecursion {
30 has_no_std_attr: bool,
33 impl_lint_pass!(MainRecursion => [MAIN_RECURSION]);
35 impl LateLintPass<'_, '_> for MainRecursion {
36 fn check_crate(&mut self, _: &LateContext<'_, '_>, krate: &Crate) {
37 self.has_no_std_attr = krate.attrs.iter().any(|attr| attr.path == sym::no_std);
40 fn check_expr_post(&mut self, cx: &LateContext<'_, '_>, expr: &Expr) {
41 if self.has_no_std_attr {
46 if let ExprKind::Call(func, _) = &expr.kind;
47 if let ExprKind::Path(path) = &func.kind;
48 if let QPath::Resolved(_, path) = &path;
49 if let Some(def_id) = path.res.opt_def_id();
50 if is_entrypoint_fn(cx, def_id);
56 &format!("recursing into entrypoint `{}`", snippet(cx, func.span, "main")),
57 "consider using another function for this recursion"