Does not compile if objc has verify_message feature turned on

[bryanlarsen]

How to reproduce:

create an app that depends on both cocoa-foundation and objc with the "verify_message" feature turned on. cocoa-foundation fails to compile.

Example error (there are dozens very similar):

error[E0277]: the trait bound `*mut *mut Object: Encode` is not satisfied
    --> /Users/blarsen/.cargo/registry/src/index.crates.io-6f17d22bba15001f/cocoa-foundation-0.1.2/src/foundation.rs:1588:9
     |
1588 |         msg_send![self, writeToURL:aURL options:mask error:errorPtr]
     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |         |
     |         the trait `Encode` is not implemented for `*mut *mut Object`
     |         required by a bound introduced by this call
     |
     = help: the following other types implement trait `Encode`:
               *const Object
               *mut Object
               &'a Object
               &'a mut Object
     = note: required for `(*mut Object, NSDataWritingOptions, *mut *mut Object)` to implement `EncodeArguments`
note: required by a bound in `__send_message`
    --> /Users/blarsen/.cargo/registry/src/index.crates.io-6f17d22bba15001f/objc-0.2.7/src/message/mod.rs:186:49
     |
184  | pub unsafe fn send_message<T, A, R>(obj: *const T, sel: Sel, args: A)
     |               ------------ required by a bound in this function
185  |         -> Result<R, MessageError>
186  |         where T: Message, A: MessageArguments + EncodeArguments,
     |                                                 ^^^^^^^^^^^^^^^ required by this bound in `send_message`
     = note: this error originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)

Rationale:

I'm getting a segfault in objc::message::platform::send_unverified in a Tauri application of mine. The interwebs tell me that in this situation I should turn on the "verify_message" flag in objc, which should convert my runtime segfault into a compile time error.

And unfortunately the way rust feature flags work I believe I can't turn it on for some crates and turn it off for cocoa-foundation.

Repro specifics:

x86 Mac, MacOS 12.7.1, Rust 1.73

cargo new foo, replace Cargo.toml with

[package]
name = "foo"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
cocoa-foundation = "0.1.2"
objc = {version = "0.2.7", features = [ "verify_message" ]}

and then cargo build.