Fix escaping for objective-C identifiers (#2587)

* Escape keywords that cannot be raw identifiers

* Update tests

* Update changelog

Author: pvdrz

CHANGELOG.md

@@ -176,6 +176,9 @@
   the `incorrect_clone_impl_on_copy_type` Clippy lint.
 ## Removed
 ## Fixed
+- Bindgen no longer panics when parsing an objective-C header that includes a
+  Rust keyword that cannot be a raw identifier, such as: `self`, `crate`,
+  `super` or `Self`.
 ## Security
 
 # 0.66.1

bindgen-tests/tests/expectations/tests/objc_escape.rs

@@ -3,4 +3,5 @@
 
 @interface A
 -(void)f:(int)arg1 as:(int)arg2;
+-(void)crate:(int)self;
 @end

bindgen-tests/tests/headers/objc_escape.h

@@ -257,15 +257,21 @@ impl ObjCMethod {
                 if name.is_empty() {
                     None
                 } else {
-                    // Try to parse the current name as an identifier. This might fail if the
-                    // name is a keyword so we try to prepend "r#" to it and parse again. If
-                    // this also fails, we panic with the first error.
+                    // Try to parse the current name as an identifier. This might fail if the name
+                    // is a keyword, so we try to  "r#" to it and parse again, this could also fail
+                    // if the name is `crate`, `self`, `super` or `Self`, so we try to add the `_`
+                    // suffix to it and parse again. If this also fails, we panic with the first
+                    // error.
                     Some(
                         syn::parse_str::<Ident>(name)
                             .or_else(|err| {
                                 syn::parse_str::<Ident>(&format!("r#{}", name))
                                     .map_err(|_| err)
                             })
+                            .or_else(|err| {
+                                syn::parse_str::<Ident>(&format!("{}_", name))
+                                    .map_err(|_| err)
+                            })
                             .expect("Invalid identifier"),
                     )
                 }