diff options
Diffstat (limited to 'src/test/ui/regions/regions-infer-contravariance-due-to-decl.rs')
-rw-r--r-- | src/test/ui/regions/regions-infer-contravariance-due-to-decl.rs | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/src/test/ui/regions/regions-infer-contravariance-due-to-decl.rs b/src/test/ui/regions/regions-infer-contravariance-due-to-decl.rs new file mode 100644 index 000000000..fbc0cec56 --- /dev/null +++ b/src/test/ui/regions/regions-infer-contravariance-due-to-decl.rs @@ -0,0 +1,29 @@ +// Test that a type which is contravariant with respect to its region +// parameter yields an error when used in a covariant way. +// +// Note: see variance-regions-*.rs for the tests that check that the +// variance inference works in the first place. + +use std::marker; + +// This is contravariant with respect to 'a, meaning that +// Contravariant<'foo> <: Contravariant<'static> because +// 'foo <= 'static +struct Contravariant<'a> { + marker: marker::PhantomData<&'a()> +} + +fn use_<'short,'long>(c: Contravariant<'short>, + s: &'short isize, + l: &'long isize, + _where:Option<&'short &'long ()>) { + + // Test whether Contravariant<'short> <: Contravariant<'long>. Since + // 'short <= 'long, this would be true if the Contravariant type were + // covariant with respect to its parameter 'a. + + let _: Contravariant<'long> = c; + //~^ ERROR lifetime may not live long enough +} + +fn main() {} |