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rustc: disallow cloning HIR nodes.
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@eddyb
eddyb committed Jun 19, 2019
1 parent 887feee commit 673c3fc
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Showing 12 changed files with 476 additions and 474 deletions.
103 changes: 48 additions & 55 deletions src/librustc/hir/lowering.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -608,15 +608,7 @@ impl<'a> LoweringContext<'a> {
});

if let Some(hir_id) = item_hir_id {
let item_generics = match self.lctx.items.get(&hir_id).unwrap().node {
hir::ItemKind::Impl(_, _, _, ref generics, ..)
| hir::ItemKind::Trait(_, _, ref generics, ..) => {
generics.params.clone()
}
_ => HirVec::new(),
};

self.lctx.with_parent_impl_lifetime_defs(&item_generics, |this| {
self.lctx.with_parent_item_lifetime_defs(hir_id, |this| {
let this = &mut ItemLowerer { lctx: this };
if let ItemKind::Impl(.., ref opt_trait_ref, _, _) = item.node {
this.with_trait_impl_ref(opt_trait_ref, |this| {
Expand Down Expand Up @@ -1054,14 +1046,22 @@ impl<'a> LoweringContext<'a> {
// This should only be used with generics that have already had their
// in-band lifetimes added. In practice, this means that this function is
// only used when lowering a child item of a trait or impl.
fn with_parent_impl_lifetime_defs<T, F>(&mut self,
params: &HirVec<hir::GenericParam>,
fn with_parent_item_lifetime_defs<T, F>(&mut self,
parent_hir_id: hir::HirId,
f: F
) -> T where
F: FnOnce(&mut LoweringContext<'_>) -> T,
{
let old_len = self.in_scope_lifetimes.len();
let lt_def_names = params.iter().filter_map(|param| match param.kind {

let parent_generics = match self.items.get(&parent_hir_id).unwrap().node {
hir::ItemKind::Impl(_, _, _, ref generics, ..)
| hir::ItemKind::Trait(_, _, ref generics, ..) => {
&generics.params[..]
}
_ => &[],
};
let lt_def_names = parent_generics.iter().filter_map(|param| match param.kind {
hir::GenericParamKind::Lifetime { .. } => Some(param.name.ident().modern()),
_ => None,
});
Expand Down Expand Up @@ -1113,8 +1113,7 @@ impl<'a> LoweringContext<'a> {

lowered_generics.params = lowered_generics
.params
.iter()
.cloned()
.into_iter()
.chain(in_band_defs)
.collect();

Expand Down Expand Up @@ -3114,8 +3113,8 @@ impl<'a> LoweringContext<'a> {
&NodeMap::default(),
itctx.reborrow(),
);
let trait_ref = self.with_parent_impl_lifetime_defs(
&bound_generic_params,
let trait_ref = self.with_in_scope_lifetime_defs(
&p.bound_generic_params,
|this| this.lower_trait_ref(&p.trait_ref, itctx),
);

Expand Down Expand Up @@ -3602,8 +3601,7 @@ impl<'a> LoweringContext<'a> {
// Essentially a single `use` which imports two names is desugared into
// two imports.
for (res, &new_node_id) in resolutions.zip([id1, id2].iter()) {
let vis = vis.clone();
let ident = ident.clone();
let ident = *ident;
let mut path = path.clone();
for seg in &mut path.segments {
seg.id = self.sess.next_node_id();
Expand All @@ -3616,19 +3614,7 @@ impl<'a> LoweringContext<'a> {
let path =
this.lower_path_extra(res, &path, ParamMode::Explicit, None);
let item = hir::ItemKind::Use(P(path), hir::UseKind::Single);
let vis_kind = match vis.node {
hir::VisibilityKind::Public => hir::VisibilityKind::Public,
hir::VisibilityKind::Crate(sugar) => hir::VisibilityKind::Crate(sugar),
hir::VisibilityKind::Inherited => hir::VisibilityKind::Inherited,
hir::VisibilityKind::Restricted { ref path, hir_id: _ } => {
let path = this.renumber_segment_ids(path);
hir::VisibilityKind::Restricted {
path,
hir_id: this.next_id(),
}
}
};
let vis = respan(vis.span, vis_kind);
let vis = this.rebuild_vis(&vis);

this.insert_item(
hir::Item {
Expand Down Expand Up @@ -3692,8 +3678,6 @@ impl<'a> LoweringContext<'a> {
for &(ref use_tree, id) in trees {
let new_hir_id = self.lower_node_id(id);

let mut vis = vis.clone();
let mut ident = ident.clone();
let mut prefix = prefix.clone();

// Give the segments new node-ids since they are being cloned.
Expand All @@ -3707,27 +3691,16 @@ impl<'a> LoweringContext<'a> {
// own its own names, we have to adjust the owner before
// lowering the rest of the import.
self.with_hir_id_owner(id, |this| {
let mut vis = this.rebuild_vis(&vis);
let mut ident = *ident;

let item = this.lower_use_tree(use_tree,
&prefix,
id,
&mut vis,
&mut ident,
attrs);

let vis_kind = match vis.node {
hir::VisibilityKind::Public => hir::VisibilityKind::Public,
hir::VisibilityKind::Crate(sugar) => hir::VisibilityKind::Crate(sugar),
hir::VisibilityKind::Inherited => hir::VisibilityKind::Inherited,
hir::VisibilityKind::Restricted { ref path, hir_id: _ } => {
let path = this.renumber_segment_ids(path);
hir::VisibilityKind::Restricted {
path: path,
hir_id: this.next_id(),
}
}
};
let vis = respan(vis.span, vis_kind);

this.insert_item(
hir::Item {
hir_id: new_hir_id,
Expand Down Expand Up @@ -3773,15 +3746,35 @@ impl<'a> LoweringContext<'a> {
/// Paths like the visibility path in `pub(super) use foo::{bar, baz}` are repeated
/// many times in the HIR tree; for each occurrence, we need to assign distinct
/// `NodeId`s. (See, e.g., #56128.)
fn renumber_segment_ids(&mut self, path: &P<hir::Path>) -> P<hir::Path> {
debug!("renumber_segment_ids(path = {:?})", path);
let mut path = path.clone();
for seg in path.segments.iter_mut() {
if seg.hir_id.is_some() {
seg.hir_id = Some(self.next_id());
}
fn rebuild_use_path(&mut self, path: &hir::Path) -> hir::Path {
debug!("rebuild_use_path(path = {:?})", path);
let segments = path.segments.iter().map(|seg| hir::PathSegment {
ident: seg.ident,
hir_id: seg.hir_id.map(|_| self.next_id()),
res: seg.res,
args: None,
infer_args: seg.infer_args,
}).collect();
hir::Path {
span: path.span,
res: path.res,
segments,
}
path
}

fn rebuild_vis(&mut self, vis: &hir::Visibility) -> hir::Visibility {
let vis_kind = match vis.node {
hir::VisibilityKind::Public => hir::VisibilityKind::Public,
hir::VisibilityKind::Crate(sugar) => hir::VisibilityKind::Crate(sugar),
hir::VisibilityKind::Inherited => hir::VisibilityKind::Inherited,
hir::VisibilityKind::Restricted { ref path, hir_id: _ } => {
hir::VisibilityKind::Restricted {
path: P(self.rebuild_use_path(path)),
hir_id: self.next_id(),
}
}
};
respan(vis.span, vis_kind)
}

fn lower_trait_item(&mut self, i: &TraitItem) -> hir::TraitItem {
Expand Down
10 changes: 5 additions & 5 deletions src/librustc/hir/map/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -51,11 +51,11 @@ impl<'hir> Entry<'hir> {
}
}

fn fn_decl(&self) -> Option<&FnDecl> {
fn fn_decl(&self) -> Option<&'hir FnDecl> {
match self.node {
Node::Item(ref item) => {
match item.node {
ItemKind::Fn(ref fn_decl, _, _, _) => Some(&fn_decl),
ItemKind::Fn(ref fn_decl, _, _, _) => Some(fn_decl),
_ => None,
}
}
Expand All @@ -76,7 +76,7 @@ impl<'hir> Entry<'hir> {

Node::Expr(ref expr) => {
match expr.node {
ExprKind::Closure(_, ref fn_decl, ..) => Some(&fn_decl),
ExprKind::Closure(_, ref fn_decl, ..) => Some(fn_decl),
_ => None,
}
}
Expand Down Expand Up @@ -412,9 +412,9 @@ impl<'hir> Map<'hir> {
self.forest.krate.body(id)
}

pub fn fn_decl_by_hir_id(&self, hir_id: HirId) -> Option<FnDecl> {
pub fn fn_decl_by_hir_id(&self, hir_id: HirId) -> Option<&'hir FnDecl> {
if let Some(entry) = self.find_entry(hir_id) {
entry.fn_decl().cloned()
entry.fn_decl()
} else {
bug!("no entry for hir_id `{}`", hir_id)
}
Expand Down
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