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Diffstat (limited to '')
-rw-r--r-- | src/test/ui/issues/issue-41936-variance-coerce-unsized-cycle.rs | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/test/ui/issues/issue-41936-variance-coerce-unsized-cycle.rs b/src/test/ui/issues/issue-41936-variance-coerce-unsized-cycle.rs new file mode 100644 index 000000000..3d678ba04 --- /dev/null +++ b/src/test/ui/issues/issue-41936-variance-coerce-unsized-cycle.rs @@ -0,0 +1,30 @@ +// check-pass +#![allow(dead_code)] +// Regression test for #41936. The coerce-unsized trait check in +// coherence was using subtyping, which triggered variance +// computation, which failed because it required type info for fields +// that had not (yet) been computed. + +#![feature(unsize)] +#![feature(coerce_unsized)] + +use std::{marker,ops}; + +// Change the array to a non-array, and error disappears +// Adding a new field to the end keeps the error +struct LogDataBuf([u8;8]); + +struct Aref<T: ?Sized> +{ + // Inner structure triggers the error, removing the inner removes the message. + ptr: Box<ArefInner<T>>, +} +impl<T: ?Sized + marker::Unsize<U>, U: ?Sized> ops::CoerceUnsized<Aref<U>> for Aref<T> {} + +struct ArefInner<T: ?Sized> +{ + // Even with this field commented out, the error is raised. + data: T, +} + +fn main(){} |