Add "better" edition handling on lint-docs tool

Author: spastorino

compiler/rustc_lint_defs/src/builtin.rs

@@ -3803,7 +3803,7 @@ declare_lint! {
 ///
 /// ### Example
 ///
-/// ```rust,compile_fail
+/// ```rust,edition2018,compile_fail
 /// #![deny(rust_2021_incompatible_or_patterns)]
 ///
 /// macro_rules! match_any {
@@ -3843,7 +3843,7 @@ declare_lint! {
 ///
 /// ### Example
 ///
-/// ```rust,compile_fail
+/// ```rust,edition2018,compile_fail
 /// #![deny(rust_2021_prelude_collisions)]
 ///
 /// trait Foo {

src/tools/lint-docs/src/lib.rs

@@ -441,10 +441,19 @@ impl<'a> LintExtractor<'a> {
  fs::write(&tempfile, source)
 .map_err(|e| format!("failed to write {}: {}", tempfile.display(), e))?;
 letmut cmd = Command::new(self.rustc_path);
-if options.contains(&"edition2015"){
+if options.contains(&"edition2024"){
+ cmd.arg("--edition=2024");
+}elseif options.contains(&"edition2021"){
+ cmd.arg("--edition=2021");
+}elseif options.contains(&"edition2018"){
+ cmd.arg("--edition=2018");
+}elseif options.contains(&"edition2015"){
  cmd.arg("--edition=2015");
+}elseif options.contains(&"edition"){
+panic!("lint-docs: unknown edition");
 }else{
- cmd.arg("--edition=2018");
+// defaults to latest edition
+ cmd.arg("--edition=2021");
 }
  cmd.arg("--error-format=json");
  cmd.arg("--target").arg(self.rustc_target);