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Diffstat (limited to '')
-rw-r--r-- | src/test/ui/impl-trait/unsafety-checking-cycle.rs | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/test/ui/impl-trait/unsafety-checking-cycle.rs b/src/test/ui/impl-trait/unsafety-checking-cycle.rs new file mode 100644 index 000000000..4a5831c5b --- /dev/null +++ b/src/test/ui/impl-trait/unsafety-checking-cycle.rs @@ -0,0 +1,32 @@ +// Ensure that we don't get a cycle error from trying to determine whether an +// opaque type implements `Freeze` in safety checking, when it doesn't matter. + +// check-pass + +#![feature(rustc_attrs)] + +struct AnyValue<T>(T); + +// No need to check for `Freeze` here, there's no +// `rustc_layout_scalar_valid_range_start` involved. +fn not_restricted(c: bool) -> impl Sized { + if c { + let x = AnyValue(not_restricted(false)); + &x.0; + } + 2u32 +} + +#[rustc_layout_scalar_valid_range_start(1)] +struct NonZero<T>(T); + +// No need to check for `Freeze` here, we're not borrowing the field. +fn not_field(c: bool) -> impl Sized { + if c { + let x = unsafe { NonZero(not_field(false)) }; + &x; + } + 5u32 +} + +fn main() {} |