diff options
Diffstat (limited to 'src/test/ui/wf/wf-packed-on-proj-of-type-as-unimpl-trait.rs')
-rw-r--r-- | src/test/ui/wf/wf-packed-on-proj-of-type-as-unimpl-trait.rs | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/test/ui/wf/wf-packed-on-proj-of-type-as-unimpl-trait.rs b/src/test/ui/wf/wf-packed-on-proj-of-type-as-unimpl-trait.rs new file mode 100644 index 000000000..d0167c8c2 --- /dev/null +++ b/src/test/ui/wf/wf-packed-on-proj-of-type-as-unimpl-trait.rs @@ -0,0 +1,31 @@ +// rust-lang/rust#58158: We have special-case code to deal with case +// when a type is both packed and needs drop glue, (we move the fields +// out of their potentially unaligned locations before dropping them, +// which requires they be Sized; see PR #44884). +// +// So, we need to check if a given type needs drop-glue. That requires +// that we actually know that the concrete type, and we guard against +// the type having unknown parts (i.e. type variables) by ICE'ing in +// that scenario. +// +// But in a case where we have a projection (`Type as Trait::Assoc`) +// where `Type` does not actually implement `Trait`, we of course +// cannot have a concrete type, because there is no impl to look up +// the concrete type for the associated type `Assoc`. +// +// So, this test is just making sure that in such a case that we do +// not immediately ICE, and instead allow the underlying type error to +// surface. + +pub struct Matrix<S>(S); +pub struct DefaultAllocator; + +pub trait Allocator { type Buffer; } + +// impl Allocator for DefaultAllocator { type Buffer = (); } + +#[repr(packed)] +struct Foo(Matrix<<DefaultAllocator as Allocator>::Buffer>); +//~^ ERROR the trait bound `DefaultAllocator: Allocator` is not satisfied + +fn main() { } |