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Merged
merged 2 commits into from
Sep 2, 2021
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rustdoc: Box GenericArgs::Parenthesized.output #88522

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2d1240e
Box `GenericArgs::Parenthesized.output`
camelid Aug 23, 2021
280e167
Remove unhelpful `expect()` message
camelid Sep 1, 2021
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2 changes: 1 addition & 1 deletion src/librustdoc/clean/auto_trait.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -351,7 +351,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
.flat_map(|(ty, mut bounds)| {
if let Some(data) = ty_to_fn.get(&ty) {
let (poly_trait, output) =
(data.0.as_ref().expect("as_ref failed").clone(), data.1.as_ref().cloned());
(data.0.as_ref().unwrap().clone(), data.1.as_ref().cloned().map(Box::new));
let new_ty = match poly_trait.trait_ {
Type::ResolvedPath { ref path, ref did, ref is_generic } => {
let mut new_path = path.clone();
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7 changes: 3 additions & 4 deletions src/librustdoc/clean/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1763,10 +1763,9 @@ impl Clean<GenericArgs> for hir::GenericArgs<'_> {
fn clean(&self, cx: &mut DocContext<'_>) -> GenericArgs {
if self.parenthesized {
let output = self.bindings[0].ty().clean(cx);
GenericArgs::Parenthesized {
inputs: self.inputs().clean(cx),
output: if output != Type::Tuple(Vec::new()) { Some(output) } else { None },
}
let output =
if output != Type::Tuple(Vec::new()) { Some(Box::new(output)) } else { None };
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Personally I would use box output here 🤷 but it won't affect performance in practice, output is already on the stack.

Oh, this is the bit that breaks #83718 (comment) ! I've been looking for it.

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Personally I would use box output here 🤷

Yeah, I thought about that, but someone recently removed all the uses of box_syntax from rustdoc and other tools; I think the goal is to get rid of box_syntax eventually. IIRC from the discussion there, the newest version of LLVM has an optimization that gets rid of the perf difference, but I may be misremembering.

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Oh, this is the bit that breaks #83718 (comment) ! I've been looking for it.

Hooray! 🎉

GenericArgs::Parenthesized { inputs: self.inputs().clean(cx), output }
} else {
GenericArgs::AngleBracketed {
args: self
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4 changes: 2 additions & 2 deletions src/librustdoc/clean/simplify.rs
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Expand Up @@ -116,10 +116,10 @@ crate fn merge_bounds(
});
}
PP::Parenthesized { ref mut output, .. } => match output {
Some(o) => assert_eq!(o, rhs),
Some(o) => assert_eq!(o.as_ref(), rhs),
None => {
if *rhs != clean::Type::Tuple(Vec::new()) {
*output = Some(rhs.clone());
*output = Some(Box::new(rhs.clone()));
}
}
},
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12 changes: 11 additions & 1 deletion src/librustdoc/clean/types.rs
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Expand Up @@ -2018,15 +2018,25 @@ crate enum GenericArg {
#[derive(Clone, PartialEq, Eq, Debug, Hash)]
crate enum GenericArgs {
AngleBracketed { args: Vec<GenericArg>, bindings: Vec<TypeBinding> },
Parenthesized { inputs: Vec<Type>, output: Option<Type> },
Parenthesized { inputs: Vec<Type>, output: Option<Box<Type>> },
}

// `GenericArgs` is in every `PathSegment`, so its size can significantly
// affect rustdoc's memory usage.
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
rustc_data_structures::static_assert_size!(GenericArgs, 56);

#[derive(Clone, PartialEq, Eq, Debug, Hash)]
crate struct PathSegment {
crate name: Symbol,
crate args: GenericArgs,
}

// `PathSegment` usually occurs multiple times in every `Path`, so its size can
// significantly affect rustdoc's memory usage.
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
rustc_data_structures::static_assert_size!(PathSegment, 64);

#[derive(Clone, Debug)]
crate struct Typedef {
crate type_: Type,
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2 changes: 1 addition & 1 deletion src/librustdoc/json/conversions.rs
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Expand Up @@ -127,7 +127,7 @@ impl FromWithTcx<clean::GenericArgs> for GenericArgs {
},
Parenthesized { inputs, output } => GenericArgs::Parenthesized {
inputs: inputs.into_iter().map(|a| a.into_tcx(tcx)).collect(),
output: output.map(|a| a.into_tcx(tcx)),
output: output.map(|a| (*a).into_tcx(tcx)),
},
}
}
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