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Sep 26, 2022
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Don't duplicate region names for late-bound regions in print of Binder #101996

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456f4e8
don't duplicate late-bound region names in print of Binder
b-naber Sep 15, 2022
897adb8
bless tests
b-naber Sep 18, 2022
6118ee3
address review
b-naber Sep 21, 2022
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81 changes: 54 additions & 27 deletions compiler/rustc_middle/src/ty/print/pretty.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1562,7 +1562,9 @@ pub struct FmtPrinterData<'a, 'tcx> {
in_value: bool,
pub print_alloc_ids: bool,

// set of all named (non-anonymous) region names
used_region_names: FxHashSet<Symbol>,

region_index: usize,
binder_depth: usize,
printed_type_count: usize,
Expand Down Expand Up @@ -2118,23 +2120,31 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
where
T: Print<'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>,
{
fn name_by_region_index(index: usize) -> Symbol {
match index {
0 => Symbol::intern("'r"),
1 => Symbol::intern("'s"),
i => Symbol::intern(&format!("'t{}", i - 2)),
fn name_by_region_index(
index: usize,
available_names: &mut Vec<Symbol>,
num_available: usize,
) -> Symbol {
if let Some(name) = available_names.pop() {
name
} else {
Symbol::intern(&format!("'z{}", index - num_available))
}
}

debug!("name_all_regions");

// Replace any anonymous late-bound regions with named
// variants, using new unique identifiers, so that we can
// clearly differentiate between named and unnamed regions in
// the output. We'll probably want to tweak this over time to
// decide just how much information to give.
if self.binder_depth == 0 {
self.prepare_late_bound_region_info(value);
self.prepare_region_info(value);
}

debug!("self.used_region_names: {:?}", &self.used_region_names);

let mut empty = true;
let mut start_or_continue = |cx: &mut Self, start: &str, cont: &str| {
let w = if empty {
Expand All @@ -2151,13 +2161,24 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {

define_scoped_cx!(self);

let possible_names =
('a'..='z').rev().map(|s| Symbol::intern(&format!("'{s}"))).collect::<Vec<_>>();

let mut available_names = possible_names
.into_iter()
.filter(|name| !self.used_region_names.contains(&name))
.collect::<Vec<_>>();
debug!(?available_names);
let num_available = available_names.len();

let mut region_index = self.region_index;
let mut next_name = |this: &Self| loop {
let name = name_by_region_index(region_index);
let mut next_name = |this: &Self| {
let name = name_by_region_index(region_index, &mut available_names, num_available);
debug!(?name);
region_index += 1;
if !this.used_region_names.contains(&name) {
break name;
}
assert!(!this.used_region_names.contains(&name));

name
};

// If we want to print verbosely, then print *all* binders, even if they
Expand All @@ -2178,6 +2199,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
ty::BrAnon(_) | ty::BrEnv => {
start_or_continue(&mut self, "for<", ", ");
let name = next_name(&self);
debug!(?name);
do_continue(&mut self, name);
ty::BrNamed(CRATE_DEF_ID.to_def_id(), name)
}
Expand Down Expand Up @@ -2271,29 +2293,37 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
Ok(inner)
}

fn prepare_late_bound_region_info<T>(&mut self, value: &ty::Binder<'tcx, T>)
fn prepare_region_info<T>(&mut self, value: &ty::Binder<'tcx, T>)
where
T: TypeVisitable<'tcx>,
{
struct LateBoundRegionNameCollector<'a, 'tcx> {
used_region_names: &'a mut FxHashSet<Symbol>,
struct RegionNameCollector<'tcx> {
used_region_names: FxHashSet<Symbol>,
type_collector: SsoHashSet<Ty<'tcx>>,
}

impl<'tcx> ty::visit::TypeVisitor<'tcx> for LateBoundRegionNameCollector<'_, 'tcx> {
impl<'tcx> RegionNameCollector<'tcx> {
fn new() -> Self {
RegionNameCollector {
used_region_names: Default::default(),
type_collector: SsoHashSet::new(),
}
}
}

impl<'tcx> ty::visit::TypeVisitor<'tcx> for RegionNameCollector<'tcx> {
type BreakTy = ();

fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
trace!("address: {:p}", r.0.0);
if let ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrNamed(_, name), .. }) = *r {
self.used_region_names.insert(name);
} else if let ty::RePlaceholder(ty::PlaceholderRegion {
name: ty::BrNamed(_, name),
..
}) = *r
{

// Collect all named lifetimes. These allow us to prevent duplication
// of already existing lifetime names when introducing names for
// anonymous late-bound regions.
if let Some(name) = r.get_name() {
self.used_region_names.insert(name);
}

r.super_visit_with(self)
}

Expand All @@ -2309,12 +2339,9 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
}
}

self.used_region_names.clear();
let mut collector = LateBoundRegionNameCollector {
used_region_names: &mut self.used_region_names,
type_collector: SsoHashSet::new(),
};
let mut collector = RegionNameCollector::new();
value.visit_with(&mut collector);
self.used_region_names = collector.used_region_names;
self.region_index = 0;
}
}
Expand Down
28 changes: 28 additions & 0 deletions compiler/rustc_middle/src/ty/sty.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,17 @@ impl BoundRegionKind {
_ => false,
}
}

pub fn get_name(&self) -> Option<Symbol> {
if self.is_named() {
match *self {
BoundRegionKind::BrNamed(_, name) => return Some(name),
_ => unreachable!(),
}
}

None
}
}

pub trait Article {
Expand Down Expand Up @@ -1445,6 +1456,23 @@ impl<'tcx> Region<'tcx> {
*self.0.0
}

pub fn get_name(self) -> Option<Symbol> {
if self.has_name() {
let name = match *self {
ty::ReEarlyBound(ebr) => Some(ebr.name),
ty::ReLateBound(_, br) => br.kind.get_name(),
ty::ReFree(fr) => fr.bound_region.get_name(),
ty::ReStatic => Some(kw::StaticLifetime),
ty::RePlaceholder(placeholder) => placeholder.name.get_name(),
_ => None,
};

return name;
}

None
}

/// Is this region named by the user?
pub fn has_name(self) -> bool {
match *self {
Expand Down
6 changes: 3 additions & 3 deletions src/test/mir-opt/combine_clone_of_primitives.{impl#0}-clone.InstCombine.diff
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@
_2 = <T as Clone>::clone(move _3) -> bb1; // scope 0 at $DIR/combine_clone_of_primitives.rs:8:5: 8:9
// mir::Constant
// + span: $DIR/combine_clone_of_primitives.rs:8:5: 8:9
// + literal: Const { ty: for<'r> fn(&'r T) -> T {<T as Clone>::clone}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a T) -> T {<T as Clone>::clone}, val: Value(<ZST>) }
}

bb1: {
Expand All @@ -37,7 +37,7 @@
- _5 = <u64 as Clone>::clone(move _6) -> [return: bb2, unwind: bb4]; // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
- // mir::Constant
- // + span: $DIR/combine_clone_of_primitives.rs:9:5: 9:11
- // + literal: Const { ty: for<'r> fn(&'r u64) -> u64 {<u64 as Clone>::clone}, val: Value(<ZST>) }
- // + literal: Const { ty: for<'a> fn(&'a u64) -> u64 {<u64 as Clone>::clone}, val: Value(<ZST>) }
+ _6 = _7; // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
+ _5 = (*_6); // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
+ goto -> bb2; // scope 0 at $DIR/combine_clone_of_primitives.rs:9:5: 9:11
Expand All @@ -53,7 +53,7 @@
- _8 = <[f32; 3] as Clone>::clone(move _9) -> [return: bb3, unwind: bb4]; // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
- // mir::Constant
- // + span: $DIR/combine_clone_of_primitives.rs:10:5: 10:16
- // + literal: Const { ty: for<'r> fn(&'r [f32; 3]) -> [f32; 3] {<[f32; 3] as Clone>::clone}, val: Value(<ZST>) }
- // + literal: Const { ty: for<'a> fn(&'a [f32; 3]) -> [f32; 3] {<[f32; 3] as Clone>::clone}, val: Value(<ZST>) }
+ _9 = _10; // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
+ _8 = (*_9); // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
+ goto -> bb3; // scope 0 at $DIR/combine_clone_of_primitives.rs:10:5: 10:16
Expand Down
2 changes: 1 addition & 1 deletion src/test/mir-opt/const_promotion_extern_static.BAR.PromoteTemps.diff
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Expand Up @@ -33,7 +33,7 @@
_0 = core::slice::<impl [&i32]>::as_ptr(move _1) -> [return: bb1, unwind: bb2]; // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:44
// mir::Constant
// + span: $DIR/const-promotion-extern-static.rs:9:36: 9:42
// + literal: Const { ty: for<'r> fn(&'r [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
}

bb1: {
Expand Down
2 changes: 1 addition & 1 deletion src/test/mir-opt/const_promotion_extern_static.FOO.PromoteTemps.diff
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Expand Up @@ -35,7 +35,7 @@
_0 = core::slice::<impl [&i32]>::as_ptr(move _1) -> [return: bb1, unwind: bb2]; // scope 0 at $DIR/const-promotion-extern-static.rs:+0:31: +0:55
// mir::Constant
// + span: $DIR/const-promotion-extern-static.rs:13:47: 13:53
// + literal: Const { ty: for<'r> fn(&'r [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a [&i32]) -> *const &i32 {core::slice::<impl [&i32]>::as_ptr}, val: Value(<ZST>) }
}

bb1: {
Expand Down
2 changes: 1 addition & 1 deletion src/test/mir-opt/deduplicate_blocks.is_line_doc_comment_2.DeduplicateBlocks.diff
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Expand Up @@ -20,7 +20,7 @@
_2 = core::str::<impl str>::as_bytes(move _3) -> bb1; // scope 0 at $DIR/deduplicate_blocks.rs:+1:11: +1:23
// mir::Constant
// + span: $DIR/deduplicate_blocks.rs:5:13: 5:21
// + literal: Const { ty: for<'r> fn(&'r str) -> &'r [u8] {core::str::<impl str>::as_bytes}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a str) -> &'a [u8] {core::str::<impl str>::as_bytes}, val: Value(<ZST>) }
}

bb1: {
Expand Down
2 changes: 1 addition & 1 deletion src/test/mir-opt/derefer_complex_case.main.Derefer.diff
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Expand Up @@ -56,7 +56,7 @@
_7 = <std::slice::Iter<'_, i32> as Iterator>::next(move _8) -> bb3; // scope 1 at $DIR/derefer_complex_case.rs:+1:17: +1:26
// mir::Constant
// + span: $DIR/derefer_complex_case.rs:6:17: 6:26
// + literal: Const { ty: for<'r> fn(&'r mut std::slice::Iter<'_, i32>) -> Option<<std::slice::Iter<'_, i32> as Iterator>::Item> {<std::slice::Iter<'_, i32> as Iterator>::next}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a mut std::slice::Iter<'_, i32>) -> Option<<std::slice::Iter<'_, i32> as Iterator>::Item> {<std::slice::Iter<'_, i32> as Iterator>::next}, val: Value(<ZST>) }
}

bb3: {
Expand Down
4 changes: 2 additions & 2 deletions src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff
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@@ -1,12 +1,12 @@
- // MIR for `nrvo` before DestinationPropagation
+ // MIR for `nrvo` after DestinationPropagation

fn nrvo(_1: for<'r> fn(&'r mut [u8; 1024])) -> [u8; 1024] {
fn nrvo(_1: for<'a> fn(&'a mut [u8; 1024])) -> [u8; 1024] {
debug init => _1; // in scope 0 at $DIR/simple.rs:+0:9: +0:13
let mut _0: [u8; 1024]; // return place in scope 0 at $DIR/simple.rs:+0:39: +0:49
let mut _2: [u8; 1024]; // in scope 0 at $DIR/simple.rs:+1:9: +1:16
let _3: (); // in scope 0 at $DIR/simple.rs:+2:5: +2:19
let mut _4: for<'r> fn(&'r mut [u8; 1024]); // in scope 0 at $DIR/simple.rs:+2:5: +2:9
let mut _4: for<'a> fn(&'a mut [u8; 1024]); // in scope 0 at $DIR/simple.rs:+2:5: +2:9
let mut _5: &mut [u8; 1024]; // in scope 0 at $DIR/simple.rs:+2:10: +2:18
let mut _6: &mut [u8; 1024]; // in scope 0 at $DIR/simple.rs:+2:10: +2:18
scope 1 {
Expand Down
8 changes: 4 additions & 4 deletions src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
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Expand Up @@ -41,7 +41,7 @@
_4 = Formatter::<'_>::sign_plus(move _5) -> bb1; // scope 0 at $DIR/funky_arms.rs:+4:22: +4:37
// mir::Constant
// + span: $DIR/funky_arms.rs:15:26: 15:35
// + literal: Const { ty: for<'r> fn(&'r Formatter<'_>) -> bool {Formatter::<'_>::sign_plus}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a Formatter<'_>) -> bool {Formatter::<'_>::sign_plus}, val: Value(<ZST>) }
}

bb1: {
Expand Down Expand Up @@ -69,7 +69,7 @@
_7 = Formatter::<'_>::precision(move _8) -> bb5; // scope 3 at $DIR/funky_arms.rs:+13:30: +13:45
// mir::Constant
// + span: $DIR/funky_arms.rs:24:34: 24:43
// + literal: Const { ty: for<'r> fn(&'r Formatter<'_>) -> Option<usize> {Formatter::<'_>::precision}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a Formatter<'_>) -> Option<usize> {Formatter::<'_>::precision}, val: Value(<ZST>) }
}

bb5: {
Expand Down Expand Up @@ -100,7 +100,7 @@
_0 = float_to_exponential_common_exact::<T>(move _11, move _12, move _13, move _14, move _17) -> bb7; // scope 3 at $DIR/funky_arms.rs:+15:9: +15:87
// mir::Constant
// + span: $DIR/funky_arms.rs:26:9: 26:42
// + literal: Const { ty: for<'r, 's, 't0> fn(&'r mut Formatter<'s>, &'t0 T, Sign, u32, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_exact::<T>}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a, 'b, 'c> fn(&'a mut Formatter<'b>, &'c T, Sign, u32, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_exact::<T>}, val: Value(<ZST>) }
}

bb7: {
Expand All @@ -125,7 +125,7 @@
_0 = float_to_exponential_common_shortest::<T>(move _18, move _19, move _20, move _21) -> bb9; // scope 2 at $DIR/funky_arms.rs:+17:9: +17:68
// mir::Constant
// + span: $DIR/funky_arms.rs:28:9: 28:45
// + literal: Const { ty: for<'r, 's, 't0> fn(&'r mut Formatter<'s>, &'t0 T, Sign, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_shortest::<T>}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a, 'b, 'c> fn(&'a mut Formatter<'b>, &'c T, Sign, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_shortest::<T>}, val: Value(<ZST>) }
}

bb9: {
Expand Down
2 changes: 1 addition & 1 deletion src/test/mir-opt/inline/cycle.f.Inline.diff
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Expand Up @@ -17,7 +17,7 @@
_2 = <impl Fn() as Fn<()>>::call(move _3, move _4) -> [return: bb1, unwind: bb3]; // scope 0 at $DIR/cycle.rs:+1:5: +1:8
// mir::Constant
// + span: $DIR/cycle.rs:6:5: 6:6
// + literal: Const { ty: for<'r> extern "rust-call" fn(&'r impl Fn(), ()) -> <impl Fn() as FnOnce<()>>::Output {<impl Fn() as Fn<()>>::call}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> extern "rust-call" fn(&'a impl Fn(), ()) -> <impl Fn() as FnOnce<()>>::Output {<impl Fn() as Fn<()>>::call}, val: Value(<ZST>) }
}

bb1: {
Expand Down
6 changes: 3 additions & 3 deletions src/test/mir-opt/inline/dyn_trait.get_query.Inline.diff
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Expand Up @@ -28,7 +28,7 @@
// mir::Constant
// + span: $DIR/dyn-trait.rs:33:13: 33:21
// + user_ty: UserType(0)
// + literal: Const { ty: for<'r> fn(&'r T) -> &'r <Q as Query>::C {<Q as Query>::cache::<T>}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a T) -> &'a <Q as Query>::C {<Q as Query>::cache::<T>}, val: Value(<ZST>) }
}

bb1: {
Expand All @@ -46,9 +46,9 @@
+ _0 = <dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache(move _7) -> bb2; // scope 3 at $DIR/dyn-trait.rs:21:5: 21:22
// mir::Constant
- // + span: $DIR/dyn-trait.rs:34:5: 34:22
- // + literal: Const { ty: for<'r> fn(&'r <Q as Query>::C) {try_execute_query::<<Q as Query>::C>}, val: Value(<ZST>) }
- // + literal: Const { ty: for<'a> fn(&'a <Q as Query>::C) {try_execute_query::<<Q as Query>::C>}, val: Value(<ZST>) }
+ // + span: $DIR/dyn-trait.rs:21:7: 21:20
+ // + literal: Const { ty: for<'r> fn(&'r dyn Cache<V = <Q as Query>::V>) {<dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
+ // + literal: Const { ty: for<'a> fn(&'a dyn Cache<V = <Q as Query>::V>) {<dyn Cache<V = <Q as Query>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
}

bb2: {
Expand Down
2 changes: 1 addition & 1 deletion src/test/mir-opt/inline/dyn_trait.mk_cycle.Inline.diff
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Expand Up @@ -12,7 +12,7 @@
_0 = <dyn Cache<V = V> as Cache>::store_nocache(move _2) -> bb1; // scope 0 at $DIR/dyn-trait.rs:+1:5: +1:22
// mir::Constant
// + span: $DIR/dyn-trait.rs:21:7: 21:20
// + literal: Const { ty: for<'r> fn(&'r dyn Cache<V = V>) {<dyn Cache<V = V> as Cache>::store_nocache}, val: Value(<ZST>) }
// + literal: Const { ty: for<'a> fn(&'a dyn Cache<V = V>) {<dyn Cache<V = V> as Cache>::store_nocache}, val: Value(<ZST>) }
}

bb1: {
Expand Down
4 changes: 2 additions & 2 deletions src/test/mir-opt/inline/dyn_trait.try_execute_query.Inline.diff
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Expand Up @@ -23,9 +23,9 @@
+ _0 = <dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache(move _4) -> bb1; // scope 1 at $DIR/dyn-trait.rs:21:5: 21:22
// mir::Constant
- // + span: $DIR/dyn-trait.rs:27:5: 27:13
- // + literal: Const { ty: for<'r> fn(&'r (dyn Cache<V = <C as Cache>::V> + 'r)) {mk_cycle::<<C as Cache>::V>}, val: Value(<ZST>) }
- // + literal: Const { ty: for<'a> fn(&'a (dyn Cache<V = <C as Cache>::V> + 'a)) {mk_cycle::<<C as Cache>::V>}, val: Value(<ZST>) }
+ // + span: $DIR/dyn-trait.rs:21:7: 21:20
+ // + literal: Const { ty: for<'r> fn(&'r dyn Cache<V = <C as Cache>::V>) {<dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
+ // + literal: Const { ty: for<'a> fn(&'a dyn Cache<V = <C as Cache>::V>) {<dyn Cache<V = <C as Cache>::V> as Cache>::store_nocache}, val: Value(<ZST>) }
}

bb1: {
Expand Down
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