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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/hr-subtype/hr-subtype.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/hr-subtype/hr-subtype.rs')
-rw-r--r-- | src/test/ui/hr-subtype/hr-subtype.rs | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/src/test/ui/hr-subtype/hr-subtype.rs b/src/test/ui/hr-subtype/hr-subtype.rs new file mode 100644 index 000000000..c770e0de8 --- /dev/null +++ b/src/test/ui/hr-subtype/hr-subtype.rs @@ -0,0 +1,111 @@ +// Targeted tests for the higher-ranked subtyping code. + +#![allow(dead_code)] + +// revisions: bound_a_vs_bound_a +// revisions: bound_a_vs_bound_b +// revisions: bound_inv_a_vs_bound_inv_b +// revisions: bound_co_a_vs_bound_co_b +// revisions: bound_a_vs_free_x +// revisions: free_x_vs_free_x +// revisions: free_x_vs_free_y +// revisions: free_inv_x_vs_free_inv_y +// revisions: bound_a_b_vs_bound_a +// revisions: bound_co_a_b_vs_bound_co_a +// revisions: bound_contra_a_contra_b_ret_co_a +// revisions: bound_co_a_co_b_ret_contra_a +// revisions: bound_inv_a_b_vs_bound_inv_a +// revisions: bound_a_b_ret_a_vs_bound_a_ret_a + +//[bound_a_vs_bound_a] check-pass +//[bound_a_vs_bound_b] check-pass +//[bound_inv_a_vs_bound_inv_b] check-pass +//[bound_co_a_vs_bound_co_b] check-pass +//[free_x_vs_free_x] check-pass +//[bound_co_a_b_vs_bound_co_a] check-pass +//[bound_co_a_co_b_ret_contra_a] check-pass +//[bound_a_b_vs_bound_a] check-pass +//[bound_contra_a_contra_b_ret_co_a] check-pass + +fn gimme<T>(_: Option<T>) {} + +struct Inv<'a> { + x: *mut &'a u32, +} + +struct Co<'a> { + x: fn(&'a u32), +} + +struct Contra<'a> { + x: &'a u32, +} + +macro_rules! check { + ($rev:ident: ($t1:ty, $t2:ty)) => { + #[cfg($rev)] + fn subtype<'x, 'y: 'x, 'z: 'y>() { + gimme::<$t2>(None::<$t1>); + //[free_inv_x_vs_free_inv_y]~^ ERROR + } + + #[cfg($rev)] + fn supertype<'x, 'y: 'x, 'z: 'y>() { + gimme::<$t1>(None::<$t2>); + //[bound_a_vs_free_x]~^ ERROR + //[free_x_vs_free_y]~^^ ERROR + //[bound_inv_a_b_vs_bound_inv_a]~^^^ ERROR + //[bound_inv_a_b_vs_bound_inv_a]~| ERROR + //[bound_a_b_ret_a_vs_bound_a_ret_a]~^^^^^ ERROR + //[free_inv_x_vs_free_inv_y]~^^^^^^ ERROR + } + }; +} + +// If both have bound regions, they are equivalent, regardless of +// variant. +check! { bound_a_vs_bound_a: (for<'a> fn(&'a u32), +for<'a> fn(&'a u32)) } +check! { bound_a_vs_bound_b: (for<'a> fn(&'a u32), +for<'b> fn(&'b u32)) } +check! { bound_inv_a_vs_bound_inv_b: (for<'a> fn(Inv<'a>), +for<'b> fn(Inv<'b>)) } +check! { bound_co_a_vs_bound_co_b: (for<'a> fn(Co<'a>), +for<'b> fn(Co<'b>)) } + +// Bound is a subtype of free. +check! { bound_a_vs_free_x: (for<'a> fn(&'a u32), +fn(&'x u32)) } + +// Two free regions are relatable if subtyping holds. +check! { free_x_vs_free_x: (fn(&'x u32), +fn(&'x u32)) } +check! { free_x_vs_free_y: (fn(&'x u32), +fn(&'y u32)) } +check! { free_inv_x_vs_free_inv_y: (fn(Inv<'x>), +fn(Inv<'y>)) } + +// Somewhat surprisingly, a fn taking two distinct bound lifetimes and +// a fn taking one bound lifetime can be interchangeable, but only if +// we are co- or contra-variant with respect to both lifetimes. +// +// The reason is: +// - if we are covariant, then 'a and 'b can be set to the call-site +// intersection; +// - if we are contravariant, then 'a can be inferred to 'static. +check! { bound_a_b_vs_bound_a: (for<'a,'b> fn(&'a u32, &'b u32), +for<'a> fn(&'a u32, &'a u32)) } +check! { bound_co_a_b_vs_bound_co_a: (for<'a,'b> fn(Co<'a>, Co<'b>), +for<'a> fn(Co<'a>, Co<'a>)) } +check! { bound_contra_a_contra_b_ret_co_a: (for<'a,'b> fn(Contra<'a>, Contra<'b>) -> Co<'a>, +for<'a> fn(Contra<'a>, Contra<'a>) -> Co<'a>) } +check! { bound_co_a_co_b_ret_contra_a: (for<'a,'b> fn(Co<'a>, Co<'b>) -> Contra<'a>, +for<'a> fn(Co<'a>, Co<'a>) -> Contra<'a>) } + +// If we make those lifetimes invariant, then the two types are not interchangeable. +check! { bound_inv_a_b_vs_bound_inv_a: (for<'a,'b> fn(Inv<'a>, Inv<'b>), +for<'a> fn(Inv<'a>, Inv<'a>)) } +check! { bound_a_b_ret_a_vs_bound_a_ret_a: (for<'a,'b> fn(&'a u32, &'b u32) -> &'a u32, +for<'a> fn(&'a u32, &'a u32) -> &'a u32) } + +fn main() {} |