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book: size and align in trait object vtables are used #39191

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Jan 24, 2017
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book: size and align in trait object vtables are used #39191

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book: size and align in trait object vtables are used
cesarb Jan 19, 2017
c7b092b
No need to mention how these fields are used
cesarb Jan 20, 2017
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5 changes: 1 addition & 4 deletions src/doc/book/trait-objects.md
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Expand Up @@ -263,10 +263,7 @@ any resources of the vtable’s type: for `u8` it is trivial, but for `String` i
will free the memory. This is necessary for owning trait objects like
`Box<Foo>`, which need to clean-up both the `Box` allocation as well as the
internal type when they go out of scope. The `size` and `align` fields store
the size of the erased type, and its alignment requirements; these are
essentially unused at the moment since the information is embedded in the
destructor, but will be used in the future, as trait objects are progressively
made more flexible.
the size of the erased type, and its alignment requirements.

Suppose we’ve got some values that implement `Foo`. The explicit form of
construction and use of `Foo` trait objects might look a bit like (ignoring the
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