Auto merge of rust-lang#5023 - rust-lang:doc-main, r=phansch

Omit doc safety/errors header checking for main

This omits checking `main` methods, which are not usually documented in the way the others are.

changelog: none

Author: bors

clippy_lints/src/doc.rs

@@ -1,4 +1,4 @@
-use crate::utils::{match_type, paths, return_ty, span_lint};
+use crate::utils::{is_entrypoint_fn, match_type, paths, return_ty, span_lint};
 use itertools::Itertools;
 use rustc::lint::in_external_macro;
 use rustc_data_structures::fx::FxHashSet;
@@ -153,7 +153,9 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for DocMarkdown {
         let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
         match item.kind {
             hir::ItemKind::Fn(ref sig, ..) => {
-                if !in_external_macro(cx.tcx.sess, item.span) {
+                if !(is_entrypoint_fn(cx, cx.tcx.hir().local_def_id(item.hir_id))
+                    || in_external_macro(cx.tcx.sess, item.span))
+                {
                     lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers);
                 }
             },

tests/ui/doc_errors.rs

@@ -61,4 +61,6 @@ impl Trait1 for Struct1 {
     }
 }
 
-fn main() {}
+fn main() -> Result<(), ()> {
+    Ok(())
+}