bjoernager/rust
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avoid manual Debug impls by adding extra Provenance bounds to types

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I wish the derive macro would support adding extra where clauses...
This commit is contained in:
Ralf Jung 2021-07-16 19:50:59 +02:00
parent a5299fb688
commit efbee50600
4 changed files with 51 additions and 152 deletions
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8
compiler/rustc_middle/src/mir/interpret/pointer.rs
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@ -86,7 +86,9 @@ impl<T: HasDataLayout> PointerArithmetic for T {}
/// This trait abstracts over the kind of provenance that is associated with a `Pointer`. It is
/// mostly opaque; the `Machine` trait extends it with some more operations that also have access to
/// some global state.
pub trait Provenance: Copy {
/// We don't actually care about this `Debug` bound (we use `Provenance::fmt` to format the entire
/// pointer), but `derive` adds some unecessary bounds.
pub trait Provenance: Copy + fmt::Debug {
/// Says whether the `offset` field of `Pointer`s with this provenance is the actual physical address.
/// If `true, ptr-to-int casts work by simply discarding the provenance.
/// If `false`, ptr-to-int casts are not supported. The offset *must* be relative in that case.
@ -142,14 +144,14 @@ static_assert_size!(Pointer, 16);
// all the Miri types.
impl<Tag: Provenance> fmt::Debug for Pointer<Tag> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
Tag::fmt(self, f)
Provenance::fmt(self, f)
}
}
impl<Tag: Provenance> fmt::Debug for Pointer<Option<Tag>> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self.provenance {
Some(tag) => Tag::fmt(&Pointer::new(tag, self.offset), f),
Some(tag) => Provenance::fmt(&Pointer::new(tag, self.offset), f),
None => write!(f, "0x{:x}", self.offset.bytes()),
}
}