Make vtables non-zero-size to fix a rustc warning. #597
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r=me |
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This fails with: Compiling tests_expectations v0.1.0 (file:///home/simon/projects/servo-deps/rust-bindgen/tests/expectations)
error[E0277]: the trait bound `std::os::raw::c_void: std::default::Default` is not satisfied
--> tests/vtable_recursive_sig.rs:27:33
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27 | pub struct Base__bindgen_vtable(::std::os::raw::c_void);
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= note: required by `std::default::Default::default`I think it’s some |
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Seems like that would prevent us from deriving What about making it |
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How was |
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Specifically, the code generated before this PR was: #[repr(C)]
#[derive(Default)]
pub struct Base__bindgen_vtable {
}
#[repr(C)]
#[derive(Debug, Copy)]
pub struct Base {
pub vtable_: *const Base__bindgen_vtable,
}
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It's |
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Right, but it's needed to derive |
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Is it? That would require |
| @@ -716,7 +716,9 @@ impl<'a> CodeGenerator for Vtable<'a> { | |||
| .item() | |||
| .pub_() | |||
| .with_attrs(attributes) | |||
There was a problem hiding this comment.
Whoops, you're totally right, you only need to remove the if a few lines above this one that pushes the Default attr :)
``` warning: found non-foreign-function-safe member in struct marked #[repr(C)]: found zero-size struct in foreign module, consider adding a member to this struct ```
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@bors-servo r=fitzgen,emilio Thanks! |
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📌 Commit f67967a has been approved by |
Make vtables non-zero-size to fix a rustc warning. ``` warning: found non-foreign-function-safe member in struct marked #[repr(C)]: found zero-size struct in foreign module, consider adding a member to this struct ``` Emilio said on IRC: > the empty vtable means that we don't care of figuring out the proper vtable layout, so we create an empty struct Sounds like all that matters is to have a pointer, we don’t look at the data behind it. Using `c_void` seems appropriate, then.
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☀️ Test successful - status-travis |
Emilio said on IRC:
Sounds like all that matters is to have a pointer, we don’t look at the data behind it. Using
c_voidseems appropriate, then.