Fix span placement on extern functions

macro/src/expand.rs

@@ -632,22 +632,26 @@ fn expand_cxx_function_shim(efn: &ExternFn, types: &Types) -> TokenStream {
         }
     };
     let mut dispatch = quote!(#setup #expr);
+    let visibility = efn.visibility;
     let unsafety = &efn.sig.unsafety;
     if unsafety.is_none() {
         dispatch = quote!(unsafe { #dispatch });
     }
+    let fn_token = efn.sig.fn_token;
     let ident = &efn.name.rust;
     let generics = &efn.generics;
+    let arg_list = quote_spanned!(efn.sig.paren_token.span=> (#(#all_args,)*));
+    let fn_body = quote_spanned!(efn.semi_token.span=> {
+        extern "C" {
+            #decl
+        }
+        #trampolines
+        #dispatch
+    });
     let function_shim = quote! {
         #doc
         #attrs
-        pub #unsafety fn #ident #generics(#(#all_args,)*) #ret {
-            extern "C" {
-                #decl
-            }
-            #trampolines
-            #dispatch
-        }
+        #visibility #unsafety #fn_token #ident #generics #arg_list #ret #fn_body
     };
     match &efn.receiver {
         None => function_shim,

syntax/mod.rs

@@ -113,6 +113,7 @@ pub struct ExternFn {
     pub lang: Lang,
     pub doc: Doc,
     pub attrs: OtherAttrs,
+    pub visibility: Token![pub],
     pub name: Pair,
     pub sig: Signature,
     pub semi_token: Token![;],

syntax/parse.rs

@@ -597,6 +597,12 @@ fn parse_extern_fn(
     let mut throws_tokens = None;
     let ret = parse_return_type(&foreign_fn.sig.output, &mut throws_tokens)?;
     let throws = throws_tokens.is_some();
+    let visibility = Token![pub](match foreign_fn.vis {
+        Visibility::Public(vis) => vis.pub_token.span,
+        Visibility::Crate(vis) => vis.crate_token.span,
+        Visibility::Restricted(vis) => vis.pub_token.span,
+        Visibility::Inherited => foreign_fn.sig.ident.span(),
+    });
     let unsafety = foreign_fn.sig.unsafety;
     let fn_token = foreign_fn.sig.fn_token;
     let name = pair(namespace, &foreign_fn.sig.ident, cxx_name, rust_name);
@@ -611,6 +617,7 @@ fn parse_extern_fn(
         lang,
         doc,
         attrs,
+        visibility,
         name,
         sig: Signature {
             unsafety,

tests/ui/deny_missing_docs.stderr

@@ -41,9 +41,7 @@ error: missing documentation for a type alias
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
- --> $DIR/deny_missing_docs.rs:9:1
-  |
-9 | #[cxx::bridge]
-  | ^^^^^^^^^^^^^^
-  |
-  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)
+  --> $DIR/deny_missing_docs.rs:54:9
+   |
+54 |         pub fn undocumented_foreign_fn() -> u8;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^