--enable-cxx-namespaces panics on namespace [[deprecated]] { ("[" is not a valid Ident)

Input C/C++ Header

int take(int t);
namespace [[deprecated]] {
    int helper(int t);
}

Bindgen Invocation

$ bindgen input.h --enable-cxx-namespaces -- -x c++ -std=c++17

Actual Results

bindgen aborts before emitting take:

clang diag: ... warning: 'deprecated' attribute on anonymous namespace ignored [-Wignored-attributes]
panicked at bindgen/ir/context.rs:903:9:
"[" is not a valid Ident

tokenize_namespace takes the next token after namespace as the module name. For an unnamed namespace the next token is [ from [[deprecated]].

namespace [[deprecated]] Foo does not panic (cursor spelling is Foo). Without --enable-cxx-namespaces there is no module Ident and take is emitted.

This is not #1676 (macro prefix) or #2293 (inline nested namespaces).

Expected Results

Do not abort. Ignore the attribute-specifier-seq on an unnamed namespace (clang already ignores deprecated here) and treat it like namespace { ... }.

Environment

bindgen: 0.73.1 (rust-lang/rust-bindgen 77cbc723)
clang/libclang: Homebrew clang 21.1.8
rustc: 1.97.1
target: aarch64-apple-darwin
OS: macOS

Start in bindgen/ir/context.rs at tokenize_namespace and the panic near line 903, then reproduce the issue with the shown C++ header and bindgen invocation. Done means an unnamed namespace with [[deprecated]] no longer panics, the attribute is ignored, and the take declaration is emitted.