86 lines
1.6 KiB
Rust
86 lines
1.6 KiB
Rust
trait Mirror {
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type Image;
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fn coerce(self) -> Self::Image;
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}
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impl<T> Mirror for T {
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type Image = T;
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fn coerce(self) -> Self { self }
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}
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trait Foo<'x, T> {
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fn foo(self) -> &'x T;
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}
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impl<'s, 'x, T: 'x> Foo<'x, T> for &'s T where &'s T: Foo2<'x, T> {
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fn foo(self) -> &'x T { self.foo2() }
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}
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trait Foo2<'x, T> {
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fn foo2(self) -> &'x T;
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}
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// example 1 - fails leak check
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impl<'x> Foo2<'x, u32> for &'x u32
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{
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fn foo2(self) -> &'x u32 { self }
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}
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// example 2 - OK with this issue
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impl<'x, 'a: 'x> Foo2<'x, i32> for &'a i32
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{
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fn foo2(self) -> &'x i32 { self }
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}
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// example 3 - fails due to issue #XYZ + Leak-check
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impl<'x, T> Foo2<'x, u64> for T
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where T: Mirror<Image=&'x u64>
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{
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fn foo2(self) -> &'x u64 { self.coerce() }
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}
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// example 4 - fails due to issue #XYZ
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impl<'x, 'a: 'x, T> Foo2<'x, i64> for T
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where T: Mirror<Image=&'a i64>
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{
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fn foo2(self) -> &'x i64 { self.coerce() }
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}
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trait RefFoo<T> {
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fn ref_foo(&self) -> &'static T;
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}
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impl<T> RefFoo<T> for T where for<'a> &'a T: Foo<'static, T> {
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fn ref_foo(&self) -> &'static T {
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self.foo()
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}
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}
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fn coerce_lifetime1(a: &u32) -> &'static u32
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{
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<u32 as RefFoo<u32>>::ref_foo(a)
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//~^ ERROR not general enough
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}
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fn coerce_lifetime2(a: &i32) -> &'static i32
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{
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<i32 as RefFoo<i32>>::ref_foo(a)
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//~^ ERROR not general enough
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}
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fn coerce_lifetime3(a: &u64) -> &'static u64
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{
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<u64 as RefFoo<u64>>::ref_foo(a)
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//~^ ERROR not general enough
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}
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fn coerce_lifetime4(a: &i64) -> &'static i64
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{
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<i64 as RefFoo<i64>>::ref_foo(a)
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//~^ ERROR not general enough
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}
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fn main() {}
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