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50 lines
1.3 KiB
Rust
50 lines
1.3 KiB
Rust
// Test that we consider equal regions when checking for hidden regions in
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// opaque types
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// check-pass
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// `'a == 'static` so `&'a i32` is fine as the return type
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fn equal_regions_static<'a: 'static>(x: &'a i32) -> impl Sized {
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//~^ WARNING unnecessary lifetime parameter `'a`
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x
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}
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// `'a == 'b` so `&'b i32` is fine as the return type
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fn equal_regions<'a: 'b, 'b: 'a>(x: &'b i32) -> impl Sized + 'a {
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let y: &'a i32 = x;
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let z: &'b i32 = y;
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x
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}
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// `'a == 'b` so `&'a i32` is fine as the return type
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fn equal_regions_rev<'a: 'b, 'b: 'a>(x: &'a i32) -> impl Sized + 'b {
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let y: &'a i32 = x;
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let z: &'b i32 = y;
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x
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}
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// `'a == 'b` so `*mut &'b i32` is fine as the return type
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fn equal_regions_inv<'a: 'b, 'b: 'a>(x: *mut &'b i32) -> impl Sized + 'a {
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let y: *mut &'a i32 = x;
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let z: *mut &'b i32 = y;
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x
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}
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// `'a == 'b` so `*mut &'a i32` is fine as the return type
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fn equal_regions_inv_rev<'a: 'b, 'b: 'a>(x: *mut &'a i32) -> impl Sized + 'b {
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let y: *mut &'a i32 = x;
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let z: *mut &'b i32 = y;
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x
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}
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// Should be able to infer `fn(&'static ())` as the return type.
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fn contravariant_lub<'a, 'b: 'a, 'c: 'a, 'd: 'b + 'c>(
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x: fn(&'b ()),
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y: fn(&'c ()),
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c: bool,
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) -> impl Sized + 'a {
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if c { x } else { y }
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}
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fn main() {}
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