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https://github.com/rust-lang/rust.git
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Precompute inverse binder depth
This commit is contained in:
Jack Huey
parent
6df26f897c
commit
ba3d22ed66
@ -249,6 +249,8 @@ enum Scope<'a> {
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/// requires binders of nested trait refs to be merged.
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from_poly_trait_ref: bool,
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binder_depth: u32,
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/// The late bound vars for a given item are stored by `HirId` to be
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/// queried later. However, if we enter an elision scope, we have to
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/// later append the elided bound vars to the list and need to know what
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@ -345,6 +347,7 @@ impl<'a> fmt::Debug for TruncatedScopeDebug<'a> {
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track_lifetime_uses,
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opaque_type_parent,
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from_poly_trait_ref,
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binder_depth,
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hir_id,
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s: _,
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} => f
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@ -354,6 +357,7 @@ impl<'a> fmt::Debug for TruncatedScopeDebug<'a> {
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.field("track_lifetime_uses", track_lifetime_uses)
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.field("opaque_type_parent", opaque_type_parent)
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.field("from_poly_trait_ref", from_poly_trait_ref)
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.field("binder_depth", binder_depth)
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.field("hir_id", hir_id)
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.field("s", &"..")
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.finish(),
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@ -618,6 +622,45 @@ fn late_region_as_bound_region<'tcx>(tcx: TyCtxt<'tcx>, region: &Region) -> ty::
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}
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}
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impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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fn depth(&self, concanetate: bool) -> u32 {
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let mut passed_boundary = false;
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let mut scope = self.scope;
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loop {
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match *scope {
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Scope::Root => {
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break 0;
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}
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Scope::TraitRefBoundary { s, .. } => {
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passed_boundary = true;
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scope = s;
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}
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Scope::Binder { binder_depth, from_poly_trait_ref, .. } => {
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break if concanetate {
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if passed_boundary || !from_poly_trait_ref {
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binder_depth + 1
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} else {
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binder_depth
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}
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} else {
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binder_depth + 1
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};
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}
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Scope::Elision { s, .. }
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| Scope::ObjectLifetimeDefault { s, .. }
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| Scope::TraitRefHackInner { s, .. }
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| Scope::Supertrait { s, .. }
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| Scope::Body { s, .. } => {
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scope = s;
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}
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}
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}
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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type Map = Map<'tcx>;
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@ -676,6 +719,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: false,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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};
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self.with(scope, move |_old_scope, this| {
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intravisit::walk_fn(this, fk, fd, b, s, hir_id)
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@ -801,6 +845,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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opaque_type_parent: true,
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track_lifetime_uses,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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s: ROOT_SCOPE,
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};
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self.with(scope, |old_scope, this| {
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@ -870,6 +915,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: false,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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};
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self.with(scope, |old_scope, this| {
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// a bare fn has no bounds, so everything
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@ -1063,6 +1109,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: false,
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from_poly_trait_ref: false,
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binder_depth: this.depth(false),
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};
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this.with(scope, |_old_scope, this| {
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this.visit_generics(generics);
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@ -1083,6 +1130,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: false,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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};
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self.with(scope, |_old_scope, this| {
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let scope = Scope::TraitRefBoundary { s: this.scope };
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@ -1142,6 +1190,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: true,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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};
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self.with(scope, |old_scope, this| {
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this.check_lifetime_params(old_scope, &generics.params);
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@ -1211,6 +1260,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: true,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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};
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self.with(scope, |old_scope, this| {
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this.check_lifetime_params(old_scope, &generics.params);
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@ -1324,6 +1374,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: false,
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from_poly_trait_ref: true,
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binder_depth: this.depth(false),
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};
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this.with(scope, |old_scope, this| {
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this.check_lifetime_params(old_scope, &bound_generic_params);
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@ -1370,6 +1421,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: false,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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};
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self.with(scope, |_, this| {
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intravisit::walk_param_bound(this, bound);
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@ -1516,6 +1568,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
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track_lifetime_uses: true,
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opaque_type_parent: false,
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from_poly_trait_ref: true,
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binder_depth: self.depth(true),
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};
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self.with(scope, |old_scope, this| {
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this.check_lifetime_params(old_scope, &trait_ref.bound_generic_params);
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@ -2266,6 +2319,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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opaque_type_parent: true,
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track_lifetime_uses: false,
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from_poly_trait_ref: false,
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binder_depth: self.depth(false),
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};
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self.with(scope, move |old_scope, this| {
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this.check_lifetime_params(old_scope, &generics.params);
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@ -2323,7 +2377,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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// given name or we run out of scopes.
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// search.
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let mut late_depth = 0;
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let mut in_poly_trait_ref = false;
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let mut first_binder_depth = None;
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let mut scope = self.scope;
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let mut outermost_body = None;
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let result = loop {
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@ -2341,25 +2395,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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break None;
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}
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Scope::TraitRefBoundary { s, .. } => {
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// We've exited nested poly trait refs; mark that we are no longer in nested trait refs.
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// We don't increase the late depth because this isn't a `Binder` scope.
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//
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// This came up in #83737, which boiled down to a case like this:
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//
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// ```
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// F: for<> Fn(&()) -> Box<dyn for<> Future<Output = ()> + Unpin>,
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// // ^^^^^
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// ```
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//
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// Here, as we traverse upwards from the `dyn for<>` binder, we want to reset `in_poly_trait_ref`
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// to false, so that we avoid excess contaenation when we encounter the outer `for<>` binder.
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in_poly_trait_ref = false;
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scope = s;
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}
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Scope::Binder { ref lifetimes, from_poly_trait_ref, s, .. } => {
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Scope::Binder { ref lifetimes, s, binder_depth, .. } => {
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match lifetime_ref.name {
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LifetimeName::Param(param_name) => {
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if let Some(&def) = lifetimes.get(¶m_name.normalize_to_macros_2_0())
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@ -2369,47 +2405,16 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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}
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_ => bug!("expected LifetimeName::Param"),
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}
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match (from_poly_trait_ref, in_poly_trait_ref) {
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// This is the first binder we see that is a poly trait ref; add one to the
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// late depth and mark that we're potentially in nested trait refs.
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(true, false) => {
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in_poly_trait_ref = true;
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late_depth += 1;
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}
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// We've already seen a binder that is a poly trait ref and this one is too,
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// that means that they are nested and we are concatenating the bound vars;
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// don't increase the late depth.
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//
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// This happens specifically with associated trait bounds like the following:
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//
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// ```
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// for<'a> T: Iterator<Item: for<'b> Foo<'a, 'b>>
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// ```
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//
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// In this case, as we traverse `for<'b>`, we would increment `late_depth` but
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// set `in_poly_trait_ref` to true. Then when we traverse `for<'a>`, we would
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// not increment `late_depth` again. (NB: Niko thinks this logic is actually
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// wrong.)
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(true, true) => {}
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// We've exited nested poly trait refs; add one to the late depth and mark
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// that we are no longer in nested trait refs
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(false, true) => {
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in_poly_trait_ref = false;
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late_depth += 1;
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}
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// Any other kind of nested binders: just increase late depth.
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(false, false) => {
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late_depth += 1;
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}
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}
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first_binder_depth = first_binder_depth.or(Some(binder_depth));
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late_depth = first_binder_depth.unwrap_or(binder_depth) - binder_depth + 1;
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scope = s;
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}
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Scope::Elision { s, .. }
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| Scope::ObjectLifetimeDefault { s, .. }
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| Scope::TraitRefHackInner { s, .. }
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| Scope::Supertrait { s, .. } => {
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| Scope::Supertrait { s, .. }
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| Scope::TraitRefBoundary { s, .. } => {
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scope = s;
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}
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}
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@ -3112,7 +3117,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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let span = lifetime_refs[0].span;
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let mut late_depth = 0;
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let mut in_poly_trait_ref = false;
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let mut first_binder_depth = None;
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let mut scope = self.scope;
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let mut lifetime_names = FxHashSet::default();
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let mut lifetime_spans = vec![];
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@ -3123,14 +3128,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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Scope::Root => break None,
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Scope::TraitRefBoundary { s, .. } => {
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// We've exited nested poly trait refs; mark that we are no longer in nested trait refs.
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// We don't increase the late depth because this isn't a `Binder` scope
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in_poly_trait_ref = false;
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scope = s;
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}
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Scope::Binder { s, ref lifetimes, from_poly_trait_ref, .. } => {
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Scope::Binder { s, ref lifetimes, binder_depth, .. } => {
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// collect named lifetimes for suggestions
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for name in lifetimes.keys() {
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if let hir::ParamName::Plain(name) = name {
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@ -3138,21 +3136,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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lifetime_spans.push(name.span);
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}
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}
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// See comments in `resolve_lifetime_ref`
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match (from_poly_trait_ref, in_poly_trait_ref) {
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(true, false) => {
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in_poly_trait_ref = true;
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late_depth += 1;
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}
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(true, true) => {}
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(false, true) => {
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in_poly_trait_ref = false;
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late_depth += 1;
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}
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(false, false) => {
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late_depth += 1;
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}
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}
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first_binder_depth = first_binder_depth.or(Some(binder_depth));
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late_depth = first_binder_depth.unwrap_or(binder_depth) - binder_depth + 1;
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scope = s;
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}
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@ -3202,7 +3187,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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Scope::ObjectLifetimeDefault { s, .. }
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| Scope::TraitRefHackInner { s, .. }
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| Scope::Supertrait { s, .. } => {
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| Scope::Supertrait { s, .. }
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| Scope::TraitRefBoundary { s, .. } => {
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scope = s;
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}
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}
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@ -3308,32 +3294,13 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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fn resolve_object_lifetime_default(&mut self, lifetime_ref: &'tcx hir::Lifetime) {
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debug!("resolve_object_lifetime_default(lifetime_ref={:?})", lifetime_ref);
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let mut late_depth = 0;
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let mut in_poly_trait_ref = false;
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let mut first_binder_depth = None;
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let mut scope = self.scope;
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let lifetime = loop {
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match *scope {
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Scope::TraitRefBoundary { s, .. } => {
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// We've exited nested poly trait refs; mark that we are no longer in nested trait refs.
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// We don't increase the late depth because this isn't a `Binder` scope
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in_poly_trait_ref = false;
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scope = s;
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}
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Scope::Binder { s, from_poly_trait_ref, .. } => {
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match (from_poly_trait_ref, in_poly_trait_ref) {
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(true, false) => {
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in_poly_trait_ref = true;
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late_depth += 1;
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}
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(true, true) => {}
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(false, true) => {
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in_poly_trait_ref = false;
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late_depth += 1;
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}
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(false, false) => {
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late_depth += 1;
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}
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}
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Scope::Binder { s, binder_depth, .. } => {
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first_binder_depth = first_binder_depth.or(Some(binder_depth));
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late_depth = first_binder_depth.unwrap_or(binder_depth) - binder_depth + 1;
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scope = s;
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}
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@ -3343,7 +3310,9 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
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Scope::ObjectLifetimeDefault { lifetime: Some(l), .. } => break l,
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Scope::TraitRefHackInner { s, .. } | Scope::Supertrait { s, .. } => {
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Scope::TraitRefHackInner { s, .. }
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| Scope::Supertrait { s, .. }
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| Scope::TraitRefBoundary { s, .. } => {
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scope = s;
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}
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}
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