Bindgen should not generate bindings for deleted member functions

[martinboehme]

Input C/C++ Header

class A {
 public:
      void foo() = delete;
};

Bindgen Invocation

bindgen input.h --generate-inline-functions -- -x c++

Actual Results

/* automatically generated by rust-bindgen 0.58.1 */

#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct A {
    pub _address: u8,
}
#[test]
fn bindgen_test_layout_A() {
    assert_eq!(
        ::std::mem::size_of::<A>(),
        1usize,
        concat!("Size of: ", stringify!(A))
    );
    assert_eq!(
        ::std::mem::align_of::<A>(),
        1usize,
        concat!("Alignment of ", stringify!(A))
    );
}
extern "C" {
    #[link_name = "\u{1}_ZN1A3fooEv"]
    pub fn A_foo(this: *mut A);
}
impl A {
    #[inline]
    pub unsafe fn foo(&mut self) {
        A_foo(self)
    }
}

Expected Results

Bindgen should not generate a binding for A::foo(). Attempting to compile and link this binding results in a linker error for an undefined symbol; this should not happen.

[martinboehme]

This may be hard to fix because, AFAICT, libclang doesn't currently offer a possibility to check whether a member function is deleted, but I thought I would report it anyway.

In the more common case where the --generate-inline-functions flag is not specified, bindgen does the right thing, somewhat coincidentally, because deleted functions are implicitly inline according to paragraph 4 of [dcl.fct.def.delete] in the C++ standard.

[martinboehme]

I think I have a plan for how to tackle this.

libclang doesn't have an API for checking if a member function is deleted, but I think we can get a good enough approximation by checking these three criteria:

• Is the member function inline (check with clang_Cursor_isFunctionInlined())?
• Does it lack a definition (check with clang_getCursorDefinition())?
• Is it not defaulted (check with clang_CXXMethod_isDefaulted())?

If these three criteria are true, I think we can relatively safely conclude that the member function is deleted and that we should therefore not generate a binding for it.