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Diffstat (limited to '')
-rw-r--r-- | src/test/ui/regions/regions-variance-covariant-use-contravariant.rs | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/src/test/ui/regions/regions-variance-covariant-use-contravariant.rs b/src/test/ui/regions/regions-variance-covariant-use-contravariant.rs new file mode 100644 index 000000000..a2183b491 --- /dev/null +++ b/src/test/ui/regions/regions-variance-covariant-use-contravariant.rs @@ -0,0 +1,27 @@ +// Test that a type which is covariant with respect to its region +// parameter yields an error when used in a contravariant way. +// +// Note: see variance-regions-*.rs for the tests that check that the +// variance inference works in the first place. + +// This is covariant with respect to 'a, meaning that +// Covariant<'foo> <: Covariant<'static> because +// 'foo <= 'static +struct Covariant<'a> { + f: extern "Rust" fn(&'a isize) +} + +fn use_<'short,'long>(c: Covariant<'long>, + s: &'short isize, + l: &'long isize, + _where:Option<&'short &'long ()>) { + + // Test whether Covariant<'long> <: Covariant<'short>. Since + // 'short <= 'long, this would be true if the Covariant type were + // contravariant with respect to its parameter 'a. + + let _: Covariant<'short> = c; + //~^ ERROR lifetime may not live long enough +} + +fn main() {} |