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Make RegionName Copy by (transitively) interning the few string v…
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…ariants
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amandasystems committed Feb 8, 2024
1 parent ad3d04c commit 795be51
Showing 1 changed file with 13 additions and 13 deletions.
26 changes: 13 additions & 13 deletions compiler/rustc_borrowck/src/diagnostics/region_name.rs
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ use crate::{universal_regions::DefiningTy, MirBorrowckCtxt};

/// A name for a particular region used in emitting diagnostics. This name could be a generated
/// name like `'1`, a name used by the user like `'a`, or a name like `'static`.
#[derive(Debug, Clone)]
#[derive(Debug, Clone, Copy)]
pub(crate) struct RegionName {
/// The name of the region (interned).
pub(crate) name: Symbol,
Expand All @@ -26,7 +26,7 @@ pub(crate) struct RegionName {
/// Denotes the source of a region that is named by a `RegionName`. For example, a free region that
/// was named by the user would get `NamedLateParamRegion` and `'static` lifetime would get `Static`.
/// This helps to print the right kinds of diagnostics.
#[derive(Debug, Clone)]
#[derive(Debug, Clone, Copy)]
pub(crate) enum RegionNameSource {
/// A bound (not free) region that was instantiated at the def site (not an HRTB).
NamedEarlyParamRegion(Span),
Expand All @@ -43,7 +43,7 @@ pub(crate) enum RegionNameSource {
/// The region corresponding to the return type of a closure.
AnonRegionFromOutput(RegionNameHighlight, &'static str),
/// The region from a type yielded by a coroutine.
AnonRegionFromYieldTy(Span, String),
AnonRegionFromYieldTy(Span, Symbol),
/// An anonymous region from an async fn.
AnonRegionFromAsyncFn(Span),
/// An anonymous region from an impl self type or trait
Expand All @@ -52,19 +52,19 @@ pub(crate) enum RegionNameSource {

/// Describes what to highlight to explain to the user that we're giving an anonymous region a
/// synthesized name, and how to highlight it.
#[derive(Debug, Clone)]
#[derive(Debug, Clone, Copy)]
pub(crate) enum RegionNameHighlight {
/// The anonymous region corresponds to a reference that was found by traversing the type in the HIR.
MatchedHirTy(Span),
/// The anonymous region corresponds to a `'_` in the generics list of a struct/enum/union.
MatchedAdtAndSegment(Span),
/// The anonymous region corresponds to a region where the type annotation is completely missing
/// from the code, e.g. in a closure arguments `|x| { ... }`, where `x` is a reference.
CannotMatchHirTy(Span, String),
CannotMatchHirTy(Span, Symbol),
/// The anonymous region corresponds to a region where the type annotation is completely missing
/// from the code, and *even if* we print out the full name of the type, the region name won't
/// be included. This currently occurs for opaque types like `impl Future`.
Occluded(Span, String),
Occluded(Span, Symbol),
}

impl RegionName {
Expand Down Expand Up @@ -249,7 +249,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
assert!(self.regioncx.universal_regions().is_universal_region(fr));

match self.region_names.borrow_mut().entry(fr) {
IndexEntry::Occupied(precomputed_name) => Some(precomputed_name.get().clone()),
IndexEntry::Occupied(precomputed_name) => Some(*precomputed_name.get()),
IndexEntry::Vacant(slot) => {
let new_name = self
.give_name_from_error_region(fr)
Expand All @@ -262,8 +262,8 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
self.give_name_if_anonymous_region_appears_in_arg_position_impl_trait(fr)
});

if let Some(new_name) = &new_name {
slot.insert(new_name.clone());
if let Some(new_name) = new_name {
slot.insert(new_name);
}
debug!("give_region_a_name: gave name {:?}", new_name);

Expand Down Expand Up @@ -460,9 +460,9 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
);
if type_name.contains(&format!("'{counter}")) {
// Only add a label if we can confirm that a region was labelled.
RegionNameHighlight::CannotMatchHirTy(span, type_name)
RegionNameHighlight::CannotMatchHirTy(span, Symbol::intern(&type_name))
} else {
RegionNameHighlight::Occluded(span, type_name)
RegionNameHighlight::Occluded(span, Symbol::intern(&type_name))
}
}

Expand Down Expand Up @@ -882,7 +882,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {

Some(RegionName {
name: self.synthesize_region_name(),
source: RegionNameSource::AnonRegionFromYieldTy(yield_span, type_name),
source: RegionNameSource::AnonRegionFromYieldTy(yield_span, Symbol::intern(&type_name)),
})
}

Expand Down Expand Up @@ -974,7 +974,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
Some(RegionName {
name: region_name,
source: RegionNameSource::AnonRegionFromArgument(
RegionNameHighlight::CannotMatchHirTy(arg_span, arg_name?.to_string()),
RegionNameHighlight::CannotMatchHirTy(arg_span, arg_name?),
),
})
} else {
Expand Down

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