Add toggle for `parse_meta_item` unsafe parsing

This makes it possible for the `unsafe(...)` syntax to only be
valid at the top level, and the `NestedMetaItem`s will automatically
reject `unsafe(...)`.

1 files changed, 3 insertions, 2 deletions

diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 886b043af24..04e2b7d45dc 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -15,6 +15,7 @@ use rustc_middle::ty;
 use rustc_middle::ty::CurrentGcx;
 use rustc_middle::util::Providers;
 use rustc_parse::new_parser_from_source_str;
+use rustc_parse::parser::attr::AllowLeadingUnsafe;
 use rustc_query_impl::QueryCtxt;
 use rustc_query_system::query::print_query_stack;
 use rustc_session::config::{self, Cfg, CheckCfg, ExpectedValues, Input, OutFileName};
@@ -67,7 +68,7 @@ pub(crate) fn parse_cfg(dcx: DiagCtxtHandle<'_>, cfgs: Vec<String>) -> Cfg {
             }
 
             match new_parser_from_source_str(&psess, filename, s.to_string()) {
-                Ok(mut parser) => match parser.parse_meta_item() {
+                Ok(mut parser) => match parser.parse_meta_item(AllowLeadingUnsafe::No) {
                     Ok(meta_item) if parser.token == token::Eof => {
                         if meta_item.path.segments.len() != 1 {
                             error!("argument key must be an identifier");
@@ -173,7 +174,7 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
             }
         };
 
-        let meta_item = match parser.parse_meta_item() {
+        let meta_item = match parser.parse_meta_item(AllowLeadingUnsafe::Yes) {
             Ok(meta_item) if parser.token == token::Eof => meta_item,
             Ok(..) => expected_error(),
             Err(err) => {