diff options
Diffstat (limited to 'src/test/ui/issues/issue-31299.rs')
-rw-r--r-- | src/test/ui/issues/issue-31299.rs | 35 |
1 files changed, 0 insertions, 35 deletions
diff --git a/src/test/ui/issues/issue-31299.rs b/src/test/ui/issues/issue-31299.rs deleted file mode 100644 index 78c3252d3..000000000 --- a/src/test/ui/issues/issue-31299.rs +++ /dev/null @@ -1,35 +0,0 @@ -// run-pass -// Regression test for #31299. This was generating an overflow error -// because of eager normalization: -// -// proving `M: Sized` requires -// - proving `PtrBack<Vec<M>>: Sized` requires -// - normalizing `Vec<<Vec<M> as Front>::Back>>: Sized` requires -// - proving `Vec<M>: Front` requires -// - `M: Sized` <-- cycle! -// -// If we skip the normalization step, though, everything goes fine. -// -// This could be fixed by implementing lazy normalization everywhere. -// -// However, we want this to work before then. For that, when checking -// whether a type is Sized we only check that the tails are Sized. As -// PtrBack does not have a tail, we don't need to normalize anything -// and this compiles - -trait Front { - type Back; -} - -impl<T> Front for Vec<T> { - type Back = Vec<T>; -} - -struct PtrBack<T: Front>(#[allow(unused_tuple_struct_fields)] Vec<T::Back>); - -struct M(#[allow(unused_tuple_struct_fields)] PtrBack<Vec<M>>); - -#[allow(unused_must_use)] -fn main() { - std::mem::size_of::<M>(); -} |