diff options
| -rw-r--r-- | compiler/rustc_abi/src/lib.rs | 10 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/syntax.rs | 18 |
2 files changed, 14 insertions, 14 deletions
diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs index b38ee52b796..c34e28ad89a 100644 --- a/compiler/rustc_abi/src/lib.rs +++ b/compiler/rustc_abi/src/lib.rs @@ -1595,21 +1595,21 @@ pub enum TagEncoding<VariantIdx: Idx> { /// Niche (values invalid for a type) encoding the discriminant. /// Note that for this encoding, the discriminant and variant index of each variant coincide! /// (This gets checked, for example, in [codegen_ssa](https://github.com/rust-lang/rust/blob/df32e15c56f582eb2bdde07711af6271f2ae660b/compiler/rustc_codegen_ssa/src/mir/operand.rs#L485).) - /// + /// /// The variant `untagged_variant` contains a niche at an arbitrary /// offset (field [`Variants::Multiple::tag_field`] of the enum). /// For a variant with variant index `i`, such that `i!=untagged_variant`, /// the tag is set to `(i - niche_variants.start).wrapping_add(niche_start)` - /// (this is wrapping arithmetic using the type of the niche field, cf. the + /// (this is wrapping arithmetic using the type of the niche field, cf. the /// [`tag_for_variant`](../rustc_const_eval/interpret/struct.InterpCx.html#method.tag_for_variant) /// query implementation). /// To recover the variant index `i` from a `tag`, the above formula has to be reversed, /// i.e. `i = (tag.wrapping_sub(niche_start))+niche_variants.start`. If `i` ends up outside /// `niche_variants`, the tag must have encoded the `untagged_variant`. - /// + /// /// For example, `Option<(usize, &T)>` is represented such that the tag for /// `None` is the null pointer in the second tuple field, and - /// `Some` is the identity function (with a non-null reference) + /// `Some` is the identity function (with a non-null reference) /// and has no additional tag, i.e. the reference being non-null uniquely identifies this variant. /// /// Other variants that are not `untagged_variant` and that are outside the `niche_variants` @@ -1617,7 +1617,7 @@ pub enum TagEncoding<VariantIdx: Idx> { /// Nonetheless, uninhabited variants can also fall into the range of `niche_variants`. Niche { untagged_variant: VariantIdx, - /// This range *may* contain `untagged_variant` or uninhabited variants; + /// This range *may* contain `untagged_variant` or uninhabited variants; /// these are then just "dead values" and not used to encode anything. niche_variants: RangeInclusive<VariantIdx>, /// This is inbounds of the type of the niche field diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs index 56f19d7929d..a651583add5 100644 --- a/compiler/rustc_middle/src/mir/syntax.rs +++ b/compiler/rustc_middle/src/mir/syntax.rs @@ -284,15 +284,15 @@ pub enum FakeBorrowKind { /// /// This is used when lowering deref patterns, where shallow borrows wouldn't prevent something /// like: - // ```compile_fail - // let mut b = Box::new(false); - // match b { - // deref!(true) => {} // not reached because `*b == false` - // _ if { *b = true; false } => {} // not reached because the guard is `false` - // deref!(false) => {} // not reached because the guard changed it - // // UB because we reached the unreachable. - // } - // ``` + /// ```compile_fail + /// let mut b = Box::new(false); + /// match b { + /// deref!(true) => {} // not reached because `*b == false` + /// _ if { *b = true; false } => {} // not reached because the guard is `false` + /// deref!(false) => {} // not reached because the guard changed it + /// // UB because we reached the unreachable. + /// } + /// ``` Deep, } |