rustdoc: make main more like rustc's.

By making non-unicode arguments a fatal error instead of a warning, we
don't need to handle what comes after, which avoids the need for an
`unchecked_claim_error_was_emitted` call.

Author: nnethercote

src/librustdoc/lib.rs

@@ -177,13 +177,16 @@ pub fn main() {
     init_logging(&early_dcx);
     rustc_driver::init_logger(&early_dcx, rustc_log::LoggerConfig::from_env("RUSTDOC_LOG"));
 
-    let exit_code = rustc_driver::catch_with_exit_code(|| match get_args(&early_dcx) {
-        Some(args) => main_args(&mut early_dcx, &args, using_internal_features),
-        _ =>
-        {
-            #[allow(deprecated)]
-            Err(ErrorGuaranteed::unchecked_claim_error_was_emitted())
-        }
+    let exit_code = rustc_driver::catch_with_exit_code(|| {
+        let args = env::args_os()
+            .enumerate()
+            .map(|(i, arg)| {
+                arg.into_string().unwrap_or_else(|arg| {
+                    early_dcx.early_fatal(format!("argument {i} is not valid Unicode: {arg:?}"))
+                })
+            })
+            .collect::<Vec<_>>();
+        main_args(&mut early_dcx, &args, using_internal_features)
     });
     process::exit(exit_code);
 }
@@ -219,19 +222,6 @@ fn init_logging(early_dcx: &EarlyDiagCtxt) {
     tracing::subscriber::set_global_default(subscriber).unwrap();
 }
 
-fn get_args(early_dcx: &EarlyDiagCtxt) -> Option<Vec<String>> {
-    env::args_os()
-        .enumerate()
-        .map(|(i, arg)| {
-            arg.into_string()
-                .map_err(|arg| {
-                    early_dcx.early_warn(format!("Argument {i} is not valid Unicode: {arg:?}"));
-                })
-                .ok()
-        })
-        .collect()
-}
-
 fn opts() -> Vec<RustcOptGroup> {
     let stable: fn(_, fn(&mut getopts::Options) -> &mut _) -> _ = RustcOptGroup::stable;
     let unstable: fn(_, fn(&mut getopts::Options) -> &mut _) -> _ = RustcOptGroup::unstable;