diff options
Diffstat (limited to 'tests/ui/layout/issue-60431-unsized-tail-behind-projection.rs')
-rw-r--r-- | tests/ui/layout/issue-60431-unsized-tail-behind-projection.rs | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/tests/ui/layout/issue-60431-unsized-tail-behind-projection.rs b/tests/ui/layout/issue-60431-unsized-tail-behind-projection.rs new file mode 100644 index 000000000..65845d2c9 --- /dev/null +++ b/tests/ui/layout/issue-60431-unsized-tail-behind-projection.rs @@ -0,0 +1,35 @@ +// rust-lang/rust#60431: This is a scenario where to determine the size of +// `&Ref<Obstack>`, we need to know the concrete type of the last field in +// `Ref<Obstack>` (i.e. its "struct tail"), and determining that concrete type +// requires normalizing `Obstack::Dyn`. +// +// The old "struct tail" computation did not perform such normalization, and so +// the compiler would ICE when trying to figure out if `Ref<Obstack>` is a +// dynamically-sized type (DST). + +// run-pass + +use std::mem; + +pub trait Arena { + type Dyn : ?Sized; +} + +pub struct DynRef { + _dummy: [()], +} + +pub struct Ref<A: Arena> { + _value: u8, + _dyn_arena: A::Dyn, +} + +pub struct Obstack; + +impl Arena for Obstack { + type Dyn = DynRef; +} + +fn main() { + assert_eq!(mem::size_of::<&Ref<Obstack>>(), mem::size_of::<&[()]>()); +} |