move needless_doctest_main to separate file

Author: y21

clippy_lints/src/doc/mod.rs

@@ -9,37 +9,31 @@ use pulldown_cmark::Event::{
 };
 use pulldown_cmark::Tag::{CodeBlock, Heading, Item, Link, Paragraph};
 use pulldown_cmark::{BrokenLink, CodeBlockKind, CowStr, Options};
-use rustc_ast::ast::{Async, Attribute, Fn, FnRetTy, ItemKind};
+use rustc_ast::ast::Attribute;
 use rustc_ast::token::CommentKind;
 use rustc_ast::{AttrKind, AttrStyle};
 use rustc_data_structures::fx::FxHashSet;
-use rustc_data_structures::sync::Lrc;
-use rustc_errors::emitter::EmitterWriter;
-use rustc_errors::{Applicability, Handler};
+use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{AnonConst, Expr};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
-use rustc_parse::maybe_new_parser_from_source_str;
-use rustc_parse::parser::ForceCollect;
 use rustc_resolve::rustdoc::{
     add_doc_fragment, attrs_to_doc_fragments, main_body_opts, source_span_for_markdown_range, DocFragment,
 };
-use rustc_session::parse::ParseSess;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::edition::Edition;
-use rustc_span::source_map::{FilePathMapping, SourceMap};
-use rustc_span::{sym, FileName, Span};
+use rustc_span::{sym, Span};
 use std::ops::Range;
-use std::{io, thread};
 use url::Url;
 
 mod link_with_quotes;
 mod markdown;
 mod missing_headers;
+mod needless_doctest_main;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -624,7 +618,7 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
                 if in_code {
                     if is_rust && !no_test {
                         let edition = edition.unwrap_or_else(|| cx.tcx.sess.edition());
-                        check_code(cx, &text, edition, range.clone(), fragments);
+                        needless_doctest_main::check(cx, &text, edition, range.clone(), fragments);
                     }
                 } else {
                     if in_link.is_some() {
@@ -645,88 +639,6 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
     headers
 }
 
-fn check_code(cx: &LateContext<'_>, text: &str, edition: Edition, range: Range<usize>, fragments: Fragments<'_>) {
-    fn has_needless_main(code: String, edition: Edition) -> bool {
-        rustc_driver::catch_fatal_errors(|| {
-            rustc_span::create_session_globals_then(edition, || {
-                let filename = FileName::anon_source_code(&code);
-
-                let fallback_bundle =
-                    rustc_errors::fallback_fluent_bundle(rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(), false);
-                let emitter = EmitterWriter::new(Box::new(io::sink()), fallback_bundle);
-                let handler = Handler::with_emitter(Box::new(emitter)).disable_warnings();
-                #[expect(clippy::arc_with_non_send_sync)] // `Lrc` is expected by with_span_handler
-                let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
-                let sess = ParseSess::with_span_handler(handler, sm);
-
-                let mut parser = match maybe_new_parser_from_source_str(&sess, filename, code) {
-                    Ok(p) => p,
-                    Err(errs) => {
-                        drop(errs);
-                        return false;
-                    },
-                };
-
-                let mut relevant_main_found = false;
-                loop {
-                    match parser.parse_item(ForceCollect::No) {
-                        Ok(Some(item)) => match &item.kind {
-                            ItemKind::Fn(box Fn {
-                                sig, body: Some(block), ..
-                            }) if item.ident.name == sym::main => {
-                                let is_async = matches!(sig.header.asyncness, Async::Yes { .. });
-                                let returns_nothing = match &sig.decl.output {
-                                    FnRetTy::Default(..) => true,
-                                    FnRetTy::Ty(ty) if ty.kind.is_unit() => true,
-                                    FnRetTy::Ty(_) => false,
-                                };
-
-                                if returns_nothing && !is_async && !block.stmts.is_empty() {
-                                    // This main function should be linted, but only if there are no other functions
-                                    relevant_main_found = true;
-                                } else {
-                                    // This main function should not be linted, we're done
-                                    return false;
-                                }
-                            },
-                            // Tests with one of these items are ignored
-                            ItemKind::Static(..)
-                            | ItemKind::Const(..)
-                            | ItemKind::ExternCrate(..)
-                            | ItemKind::ForeignMod(..)
-                            // Another function was found; this case is ignored
-                            | ItemKind::Fn(..) => return false,
-                            _ => {},
-                        },
-                        Ok(None) => break,
-                        Err(e) => {
-                            e.cancel();
-                            return false;
-                        },
-                    }
-                }
-
-                relevant_main_found
-            })
-        })
-        .ok()
-        .unwrap_or_default()
-    }
-
-    let trailing_whitespace = text.len() - text.trim_end().len();
-
-    // Because of the global session, we need to create a new session in a different thread with
-    // the edition we need.
-    let text = text.to_owned();
-    if thread::spawn(move || has_needless_main(text, edition))
-        .join()
-        .expect("thread::spawn failed")
-        && let Some(span) = fragments.span(cx, range.start..range.end - trailing_whitespace)
-    {
-        span_lint(cx, NEEDLESS_DOCTEST_MAIN, span, "needless `fn main` in doctest");
-    }
-}
-
 struct FindPanicUnwrap<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     panic_span: Option<Span>,

clippy_lints/src/doc/needless_doctest_main.rs

@@ -0,0 +1,100 @@
+use std::ops::Range;
+use std::{io, thread};
+
+use crate::doc::NEEDLESS_DOCTEST_MAIN;
+use clippy_utils::diagnostics::span_lint;
+use rustc_ast::{Async, Fn, FnRetTy, ItemKind};
+use rustc_data_structures::sync::Lrc;
+use rustc_errors::emitter::EmitterWriter;
+use rustc_errors::Handler;
+use rustc_lint::LateContext;
+use rustc_parse::maybe_new_parser_from_source_str;
+use rustc_parse::parser::ForceCollect;
+use rustc_session::parse::ParseSess;
+use rustc_span::edition::Edition;
+use rustc_span::source_map::{FilePathMapping, SourceMap};
+use rustc_span::{sym, FileName};
+
+use super::Fragments;
+
+pub fn check(cx: &LateContext<'_>, text: &str, edition: Edition, range: Range<usize>, fragments: Fragments<'_>) {
+    fn has_needless_main(code: String, edition: Edition) -> bool {
+        rustc_driver::catch_fatal_errors(|| {
+            rustc_span::create_session_globals_then(edition, || {
+                let filename = FileName::anon_source_code(&code);
+
+                let fallback_bundle =
+                    rustc_errors::fallback_fluent_bundle(rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(), false);
+                let emitter = EmitterWriter::new(Box::new(io::sink()), fallback_bundle);
+                let handler = Handler::with_emitter(Box::new(emitter)).disable_warnings();
+                #[expect(clippy::arc_with_non_send_sync)] // `Lrc` is expected by with_span_handler
+                let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
+                let sess = ParseSess::with_span_handler(handler, sm);
+
+                let mut parser = match maybe_new_parser_from_source_str(&sess, filename, code) {
+                    Ok(p) => p,
+                    Err(errs) => {
+                        drop(errs);
+                        return false;
+                    },
+                };
+
+                let mut relevant_main_found = false;
+                loop {
+                    match parser.parse_item(ForceCollect::No) {
+                        Ok(Some(item)) => match &item.kind {
+                            ItemKind::Fn(box Fn {
+                                sig, body: Some(block), ..
+                            }) if item.ident.name == sym::main => {
+                                let is_async = matches!(sig.header.asyncness, Async::Yes { .. });
+                                let returns_nothing = match &sig.decl.output {
+                                    FnRetTy::Default(..) => true,
+                                    FnRetTy::Ty(ty) if ty.kind.is_unit() => true,
+                                    FnRetTy::Ty(_) => false,
+                                };
+
+                                if returns_nothing && !is_async && !block.stmts.is_empty() {
+                                    // This main function should be linted, but only if there are no other functions
+                                    relevant_main_found = true;
+                                } else {
+                                    // This main function should not be linted, we're done
+                                    return false;
+                                }
+                            },
+                            // Tests with one of these items are ignored
+                            ItemKind::Static(..)
+                            | ItemKind::Const(..)
+                            | ItemKind::ExternCrate(..)
+                            | ItemKind::ForeignMod(..)
+                            // Another function was found; this case is ignored
+                            | ItemKind::Fn(..) => return false,
+                            _ => {},
+                        },
+                        Ok(None) => break,
+                        Err(e) => {
+                            e.cancel();
+                            return false;
+                        },
+                    }
+                }
+
+                relevant_main_found
+            })
+        })
+        .ok()
+        .unwrap_or_default()
+    }
+
+    let trailing_whitespace = text.len() - text.trim_end().len();
+
+    // Because of the global session, we need to create a new session in a different thread with
+    // the edition we need.
+    let text = text.to_owned();
+    if thread::spawn(move || has_needless_main(text, edition))
+        .join()
+        .expect("thread::spawn failed")
+        && let Some(span) = fragments.span(cx, range.start..range.end - trailing_whitespace)
+    {
+        span_lint(cx, NEEDLESS_DOCTEST_MAIN, span, "needless `fn main` in doctest");
+    }
+}