78 lines
2.0 KiB
Rust
78 lines
2.0 KiB
Rust
//@ run-pass
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// Check that item-less traits do not cause dropck to inject extra
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// region constraints.
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#![allow(non_camel_case_types)]
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#![feature(dropck_eyepatch)]
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trait UserDefined { }
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impl UserDefined for i32 { }
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impl<'a, T> UserDefined for &'a T { }
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// e.g., `impl_drop!(Send, D_Send)` expands to:
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// ```rust
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// struct D_Send<T:Send>(T);
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// impl<T:Send> Drop for D_Send<T> { fn drop(&mut self) { } }
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// ```
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macro_rules! impl_drop {
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($Bound:ident, $Id:ident) => {
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struct $Id<T: $Bound>(#[allow(dead_code)] T);
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unsafe impl <#[may_dangle] T: $Bound> Drop for $Id<T> {
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fn drop(&mut self) { }
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}
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}
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}
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impl_drop!{Send, D_Send}
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impl_drop!{Sized, D_Sized}
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// See note below regarding Issue 24895
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// impl_drop!{Copy, D_Copy}
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impl_drop!{Sync, D_Sync}
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impl_drop!{UserDefined, D_UserDefined}
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macro_rules! body {
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($id:ident) => { {
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// `_d` and `d1` are assigned the *same* lifetime by region inference ...
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let (_d, d1);
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d1 = $id(1);
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// ... we store a reference to `d1` within `_d` ...
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_d = $id(&d1);
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// ... a *conservative* dropck will thus complain, because it
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// thinks Drop of _d could access the already dropped `d1`.
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} }
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}
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fn f_send() { body!(D_Send) }
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fn f_sized() { body!(D_Sized) }
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fn f_sync() { body!(D_Sync) }
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// Issue 24895: Copy: Clone implies `impl<T:Copy> Drop for ...` can
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// access a user-defined clone() method, which causes this test case
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// to fail.
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//
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// If 24895 is resolved by removing the `Copy: Clone` relationship,
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// then this definition and the call below should be uncommented. If
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// it is resolved by deciding to keep the `Copy: Clone` relationship,
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// then this comment and the associated bits of code can all be
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// removed.
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// fn f_copy() { body!(D_Copy) }
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fn f_userdefined() { body!(D_UserDefined) }
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fn main() {
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f_send();
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f_sized();
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// See note above regarding Issue 24895.
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// f_copy();
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f_sync();
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f_userdefined();
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}
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