`_Accum` globals and constants panic (`CXType_Accum` fails the var.rs Auto/Unexposed assert)

Input C/C++ Header

const _Accum K = 7;
extern _Accum G;

Bindgen Invocation

$ bindgen input.h -- -ffixed-point

Actual Results

bindgen aborts while parsing the variable. _Accum is ISO TR 18037 / clang -ffixed-point. libclang reports CXType_Accum. Function parameters of type _Accum already go through the opaque integer fallback (u32; see #3398). Globals and const objects do not: Item::from_ty fails, and ir/var.rs then asserts that the failed type must be CXType_Auto or CXType_Unexposed.

panicked at bindgen/ir/var.rs:312:25:
Couldn't resolve constant type, and it wasn't an nondeductible auto type or unexposed type: Type(const _Accum, kind: Accum, ...)
panic in a function that cannot unwind
thread caused non-unwinding panic. aborting.

extern short _Accum and extern unsigned _Accum abort the same way. A function-only header int take(_Accum a); does not abort.

This is the same assertion text as the old _Atomic crashes (#2882 / #2920), but the type here is CXType_Accum, not _Atomic.

Expected Results

Do not abort. Skip the variable, or use the same opaque integer fallback already used for _Accum parameters.

Environment

bindgen: 0.72.1 and 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

Reproduce the panic with the provided header and bindgen invocation, then start in bindgen/ir/var.rs around the assertion and trace the failed Item::from_ty resolution for CXType_Accum. Compare this path with the existing _Accum handling for function parameters. Done means globals and const objects no longer abort and follow one of the expected outcomes: skipping the variable or using the opaque integer fallback.