transmutability: Support types with restricted validity ranges #148449
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| pub fn is_transmutable<Src, Dst>() | ||
| where | ||
| Dst: TransmuteFrom<Src, { Assume::NOTHING }>, |
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You probably want to Assume::SAFETY here, otherwise you're just getting sniped by field privacy.
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Doesn't look like it – see the .stderr output.
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Well that's not good; indicates we need to thread in the field visibility.
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Done – added a test to make sure we don't regress this.
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While you're poking around here, can you check that we didn't regress this on regular structs too? I think we might've.
| // types exist in the standard library which also | ||
| // use | ||
| // `#[rustc_layout_scalar_valid_range_(start|end)]`. | ||
| if let [field] = &variant.fields.as_slice().raw { |
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You can de-indent a bunch of this if you let-else:
| if let [field] = &variant.fields.as_slice().raw { | |
| let [field] = &variant.fields.as_slice().raw else { return Err(Err::NotYetSupported) }; |
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| pub fn is_transmutable<Src, Dst>() | ||
| where | ||
| Dst: TransmuteFrom<Src, { Assume::NOTHING }>, |
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Well that's not good; indicates we need to thread in the field visibility.
| if hi_val == max_value | ||
| && let ty::Uint(_) = *field_ty.kind() | ||
| { | ||
| Ok(Self::nonzero(field_size.bytes())) |
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The Tree returned here should be a Seq of three elements:
- a
Tree::Def(Def::Adt(..))for the struct definition - a
Tree::Def(Def::Field(..))for the field definition - the
Self::nonzerofor the field layout
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This commit moves us closer to supporting `NonZero` types, but does not get us all the way there.
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This commit moves us closer to supporting
NonZerotypes, but does not get us all the way there.Tracking issue: #99571
r? @jswrenn