Fill in long diagnostic
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@ -4698,6 +4698,55 @@ element type `T`. Also note that the error is conservatively reported even when
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the alignment of the zero-sized type is less than or equal to the data field's
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alignment.
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"##,
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E0908: r##"
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A method was called on a raw pointer whose inner type wasn't completely known.
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For example, you may have done something like:
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```compile_fail
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# #![deny(warnings)]
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let foo = &1;
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let bar = foo as *const _;
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if bar.is_null() {
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// ...
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}
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```
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Here, the type of `bar` isn't known; it could be a pointer to anything. Instead,
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specify a type for the pointer (preferably something that makes sense for the
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thing you're pointing to):
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```
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let foo = &1;
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let bar = foo as *const i32;
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if bar.is_null() {
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// ...
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}
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```
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Even though `is_null()` exists as a method on any raw pointer, Rust shows this
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error because Rust allows for `self` to have arbitrary types (behind the
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arbitrary_self_types feature flag).
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This means that someone can specify such a function:
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```ignore (cannot-doctest-feature-doesnt-exist-yet)
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impl Foo {
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fn is_null(self: *const Self) -> bool {
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// do something else
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}
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}
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```
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and now when you call `.is_null()` on a raw pointer to `Foo`, there's ambiguity.
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Given that we don't know what type the pointer is, and there's potential
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ambiguity for some types, we disallow calling methods on raw pointers when
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the type is unknown.
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"##,
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}
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register_diagnostics! {
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@ -4777,5 +4826,4 @@ register_diagnostics! {
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E0641, // cannot cast to/from a pointer with an unknown kind
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E0645, // trait aliases not finished
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E0907, // type inside generator must be known in this context
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E0908, // methods on raw pointers can only be called if the pointer type is fully known
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}
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