1 use rustc_data_structures
::base_n
;
2 use rustc_data_structures
::fx
::{FxHashMap, FxHashSet}
;
3 use rustc_data_structures
::intern
::Interned
;
5 use rustc_hir
::def
::CtorKind
;
6 use rustc_hir
::def_id
::{CrateNum, DefId}
;
7 use rustc_hir
::definitions
::{DefPathData, DisambiguatedDefPathData}
;
8 use rustc_middle
::ty
::layout
::IntegerExt
;
9 use rustc_middle
::ty
::print
::{Print, Printer}
;
10 use rustc_middle
::ty
::subst
::{GenericArg, GenericArgKind, Subst}
;
11 use rustc_middle
::ty
::{
12 self, EarlyBinder
, FloatTy
, Instance
, IntTy
, Ty
, TyCtxt
, TypeVisitable
, UintTy
,
14 use rustc_span
::symbol
::kw
;
15 use rustc_target
::abi
::Integer
;
16 use rustc_target
::spec
::abi
::Abi
;
22 pub(super) fn mangle
<'tcx
>(
24 instance
: Instance
<'tcx
>,
25 instantiating_crate
: Option
<CrateNum
>,
27 let def_id
= instance
.def_id();
28 // FIXME(eddyb) this should ideally not be needed.
29 let substs
= tcx
.normalize_erasing_regions(ty
::ParamEnv
::reveal_all(), instance
.substs
);
32 let mut cx
= &mut SymbolMangler
{
34 start_offset
: prefix
.len(),
35 paths
: FxHashMap
::default(),
36 types
: FxHashMap
::default(),
37 consts
: FxHashMap
::default(),
39 out
: String
::from(prefix
),
42 // Append `::{shim:...#0}` to shims that can coexist with a non-shim instance.
43 let shim_kind
= match instance
.def
{
44 ty
::InstanceDef
::VTableShim(_
) => Some("vtable"),
45 ty
::InstanceDef
::ReifyShim(_
) => Some("reify"),
50 cx
= if let Some(shim_kind
) = shim_kind
{
51 cx
.path_append_ns(|cx
| cx
.print_def_path(def_id
, substs
), 'S'
, 0, shim_kind
).unwrap()
53 cx
.print_def_path(def_id
, substs
).unwrap()
55 if let Some(instantiating_crate
) = instantiating_crate
{
56 cx
= cx
.print_def_path(instantiating_crate
.as_def_id(), &[]).unwrap();
58 std
::mem
::take(&mut cx
.out
)
61 pub(super) fn mangle_typeid_for_trait_ref
<'tcx
>(
63 trait_ref
: ty
::PolyExistentialTraitRef
<'tcx
>,
65 // FIXME(flip1995): See comment in `mangle_typeid_for_fnabi`.
66 let mut cx
= &mut SymbolMangler
{
69 paths
: FxHashMap
::default(),
70 types
: FxHashMap
::default(),
71 consts
: FxHashMap
::default(),
75 cx
= cx
.print_def_path(trait_ref
.def_id(), &[]).unwrap();
76 std
::mem
::take(&mut cx
.out
)
80 /// The range of distances from the root of what's
81 /// being printed, to the lifetimes in a binder.
82 /// Specifically, a `BrAnon(i)` lifetime has depth
83 /// `lifetime_depths.start + i`, going away from the
84 /// the root and towards its use site, as `i` increases.
85 /// This is used to flatten rustc's pairing of `BrAnon`
86 /// (intra-binder disambiguation) with a `DebruijnIndex`
87 /// (binder addressing), to "true" de Bruijn indices,
88 /// by subtracting the depth of a certain lifetime, from
89 /// the innermost depth at its use site.
90 lifetime_depths
: Range
<u32>,
93 struct SymbolMangler
<'tcx
> {
95 binders
: Vec
<BinderLevel
>,
98 /// The length of the prefix in `out` (e.g. 2 for `_R`).
100 /// The values are start positions in `out`, in bytes.
101 paths
: FxHashMap
<(DefId
, &'tcx
[GenericArg
<'tcx
>]), usize>,
102 types
: FxHashMap
<Ty
<'tcx
>, usize>,
103 consts
: FxHashMap
<ty
::Const
<'tcx
>, usize>,
106 impl<'tcx
> SymbolMangler
<'tcx
> {
107 fn push(&mut self, s
: &str) {
108 self.out
.push_str(s
);
111 /// Push a `_`-terminated base 62 integer, using the format
112 /// specified in the RFC as `<base-62-number>`, that is:
113 /// * `x = 0` is encoded as just the `"_"` terminator
114 /// * `x > 0` is encoded as `x - 1` in base 62, followed by `"_"`,
115 /// e.g. `1` becomes `"0_"`, `62` becomes `"Z_"`, etc.
116 fn push_integer_62(&mut self, x
: u64) {
117 if let Some(x
) = x
.checked_sub(1) {
118 base_n
::push_str(x
as u128
, 62, &mut self.out
);
123 /// Push a `tag`-prefixed base 62 integer, when larger than `0`, that is:
124 /// * `x = 0` is encoded as `""` (nothing)
125 /// * `x > 0` is encoded as the `tag` followed by `push_integer_62(x - 1)`
126 /// e.g. `1` becomes `tag + "_"`, `2` becomes `tag + "0_"`, etc.
127 fn push_opt_integer_62(&mut self, tag
: &str, x
: u64) {
128 if let Some(x
) = x
.checked_sub(1) {
130 self.push_integer_62(x
);
134 fn push_disambiguator(&mut self, dis
: u64) {
135 self.push_opt_integer_62("s", dis
);
138 fn push_ident(&mut self, ident
: &str) {
139 let mut use_punycode
= false;
140 for b
in ident
.bytes() {
142 b'_'
| b'a'
..=b'z'
| b'A'
..=b'Z'
| b'
0'
..=b'
9'
=> {}
143 0x80..=0xff => use_punycode
= true,
144 _
=> bug
!("symbol_names: bad byte {} in ident {:?}", b
, ident
),
149 let ident
= if use_punycode
{
152 // FIXME(eddyb) we should probably roll our own punycode implementation.
153 let mut punycode_bytes
= match punycode
::encode(ident
) {
154 Ok(s
) => s
.into_bytes(),
155 Err(()) => bug
!("symbol_names: punycode encoding failed for ident {:?}", ident
),
158 // Replace `-` with `_`.
159 if let Some(c
) = punycode_bytes
.iter_mut().rfind(|&&mut c
| c
== b'
-'
) {
163 // FIXME(eddyb) avoid rechecking UTF-8 validity.
164 punycode_string
= String
::from_utf8(punycode_bytes
).unwrap();
170 let _
= write
!(self.out
, "{}", ident
.len());
172 // Write a separating `_` if necessary (leading digit or `_`).
173 if let Some('_'
| '
0'
..='
9'
) = ident
.chars().next() {
180 fn path_append_ns
<'a
>(
181 mut self: &'a
mut Self,
182 print_prefix
: impl FnOnce(&'a
mut Self) -> Result
<&'a
mut Self, !>,
186 ) -> Result
<&'a
mut Self, !> {
189 self = print_prefix(self)?
;
190 self.push_disambiguator(disambiguator
as u64);
191 self.push_ident(name
);
195 fn print_backref(&mut self, i
: usize) -> Result
<&mut Self, !> {
197 self.push_integer_62((i
- self.start_offset
) as u64);
202 mut self: &'a
mut Self,
203 value
: &ty
::Binder
<'tcx
, T
>,
204 print_value
: impl FnOnce(&'a
mut Self, &T
) -> Result
<&'a
mut Self, !>,
205 ) -> Result
<&'a
mut Self, !>
207 T
: TypeVisitable
<'tcx
>,
209 let regions
= if value
.has_late_bound_regions() {
210 self.tcx
.collect_referenced_late_bound_regions(value
)
215 let mut lifetime_depths
=
216 self.binders
.last().map(|b
| b
.lifetime_depths
.end
).map_or(0..0, |i
| i
..i
);
218 let lifetimes
= regions
222 _
=> bug
!("symbol_names: non-anonymized region `{:?}` in `{:?}`", br
, value
),
225 .map_or(0, |max
| max
+ 1);
227 self.push_opt_integer_62("G", lifetimes
as u64);
228 lifetime_depths
.end
+= lifetimes
;
230 self.binders
.push(BinderLevel { lifetime_depths }
);
231 self = print_value(self, value
.as_ref().skip_binder())?
;
238 impl<'tcx
> Printer
<'tcx
> for &mut SymbolMangler
<'tcx
> {
244 type DynExistential
= Self;
247 fn tcx(&self) -> TyCtxt
<'tcx
> {
254 substs
: &'tcx
[GenericArg
<'tcx
>],
255 ) -> Result
<Self::Path
, Self::Error
> {
256 if let Some(&i
) = self.paths
.get(&(def_id
, substs
)) {
257 return self.print_backref(i
);
259 let start
= self.out
.len();
261 self = self.default_print_def_path(def_id
, substs
)?
;
263 // Only cache paths that do not refer to an enclosing
264 // binder (which would change depending on context).
265 if !substs
.iter().any(|k
| k
.has_escaping_bound_vars()) {
266 self.paths
.insert((def_id
, substs
), start
);
274 substs
: &'tcx
[GenericArg
<'tcx
>],
275 mut self_ty
: Ty
<'tcx
>,
276 mut impl_trait_ref
: Option
<ty
::TraitRef
<'tcx
>>,
277 ) -> Result
<Self::Path
, Self::Error
> {
278 let key
= self.tcx
.def_key(impl_def_id
);
279 let parent_def_id
= DefId { index: key.parent.unwrap(), ..impl_def_id }
;
281 let mut param_env
= self.tcx
.param_env_reveal_all_normalized(impl_def_id
);
282 if !substs
.is_empty() {
283 param_env
= EarlyBinder(param_env
).subst(self.tcx
, substs
);
286 match &mut impl_trait_ref
{
287 Some(impl_trait_ref
) => {
288 assert_eq
!(impl_trait_ref
.self_ty(), self_ty
);
289 *impl_trait_ref
= self.tcx
.normalize_erasing_regions(param_env
, *impl_trait_ref
);
290 self_ty
= impl_trait_ref
.self_ty();
293 self_ty
= self.tcx
.normalize_erasing_regions(param_env
, self_ty
);
297 self.push(match impl_trait_ref
{
302 // Encode impl generic params if the substitutions contain parameters (implying
303 // polymorphization is enabled) and this isn't an inherent impl.
304 if impl_trait_ref
.is_some() && substs
.iter().any(|a
| a
.has_param_types_or_consts()) {
305 self = self.path_generic_args(
308 |cx
| cx
.print_def_path(parent_def_id
, &[]),
310 key
.disambiguated_data
.disambiguator
as u64,
317 self.push_disambiguator(key
.disambiguated_data
.disambiguator
as u64);
318 self = self.print_def_path(parent_def_id
, &[])?
;
321 self = self_ty
.print(self)?
;
323 if let Some(trait_ref
) = impl_trait_ref
{
324 self = self.print_def_path(trait_ref
.def_id
, trait_ref
.substs
)?
;
330 fn print_region(self, region
: ty
::Region
<'_
>) -> Result
<Self::Region
, Self::Error
> {
331 let i
= match *region
{
332 // Erased lifetimes use the index 0, for a
333 // shorter mangling of `L_`.
336 // Late-bound lifetimes use indices starting at 1,
337 // see `BinderLevel` for more details.
338 ty
::ReLateBound(debruijn
, ty
::BoundRegion { kind: ty::BrAnon(i), .. }
) => {
339 let binder
= &self.binders
[self.binders
.len() - 1 - debruijn
.index()];
340 let depth
= binder
.lifetime_depths
.start
+ i
;
342 1 + (self.binders
.last().unwrap().lifetime_depths
.end
- 1 - depth
)
345 _
=> bug
!("symbol_names: non-erased region `{:?}`", region
),
348 self.push_integer_62(i
as u64);
352 fn print_type(mut self, ty
: Ty
<'tcx
>) -> Result
<Self::Type
, Self::Error
> {
353 // Basic types, never cached (single-character).
354 let basic_type
= match ty
.kind() {
358 ty
::Tuple(_
) if ty
.is_unit() => "u",
359 ty
::Int(IntTy
::I8
) => "a",
360 ty
::Int(IntTy
::I16
) => "s",
361 ty
::Int(IntTy
::I32
) => "l",
362 ty
::Int(IntTy
::I64
) => "x",
363 ty
::Int(IntTy
::I128
) => "n",
364 ty
::Int(IntTy
::Isize
) => "i",
365 ty
::Uint(UintTy
::U8
) => "h",
366 ty
::Uint(UintTy
::U16
) => "t",
367 ty
::Uint(UintTy
::U32
) => "m",
368 ty
::Uint(UintTy
::U64
) => "y",
369 ty
::Uint(UintTy
::U128
) => "o",
370 ty
::Uint(UintTy
::Usize
) => "j",
371 ty
::Float(FloatTy
::F32
) => "f",
372 ty
::Float(FloatTy
::F64
) => "d",
375 // Placeholders (should be demangled as `_`).
376 ty
::Param(_
) | ty
::Bound(..) | ty
::Placeholder(_
) | ty
::Infer(_
) | ty
::Error(_
) => "p",
380 if !basic_type
.is_empty() {
381 self.push(basic_type
);
385 if let Some(&i
) = self.types
.get(&ty
) {
386 return self.print_backref(i
);
388 let start
= self.out
.len();
391 // Basic types, handled above.
392 ty
::Bool
| ty
::Char
| ty
::Str
| ty
::Int(_
) | ty
::Uint(_
) | ty
::Float(_
) | ty
::Never
=> {
395 ty
::Tuple(_
) if ty
.is_unit() => unreachable
!(),
397 // Placeholders, also handled as part of basic types.
398 ty
::Param(_
) | ty
::Bound(..) | ty
::Placeholder(_
) | ty
::Infer(_
) | ty
::Error(_
) => {
402 ty
::Ref(r
, ty
, mutbl
) => {
403 self.push(match mutbl
{
404 hir
::Mutability
::Not
=> "R",
405 hir
::Mutability
::Mut
=> "Q",
408 self = r
.print(self)?
;
410 self = ty
.print(self)?
;
414 self.push(match mt
.mutbl
{
415 hir
::Mutability
::Not
=> "P",
416 hir
::Mutability
::Mut
=> "O",
418 self = mt
.ty
.print(self)?
;
421 ty
::Array(ty
, len
) => {
423 self = ty
.print(self)?
;
424 self = self.print_const(len
)?
;
428 self = ty
.print(self)?
;
433 for ty
in tys
.iter() {
434 self = ty
.print(self)?
;
439 // Mangle all nominal types as paths.
440 ty
::Adt(ty
::AdtDef(Interned(&ty
::AdtDefData { did: def_id, .. }
, _
)), substs
)
441 | ty
::FnDef(def_id
, substs
)
442 | ty
::Opaque(def_id
, substs
)
443 | ty
::Projection(ty
::ProjectionTy { item_def_id: def_id, substs }
)
444 | ty
::Closure(def_id
, substs
)
445 | ty
::Generator(def_id
, substs
, _
) => {
446 self = self.print_def_path(def_id
, substs
)?
;
448 ty
::Foreign(def_id
) => {
449 self = self.print_def_path(def_id
, &[])?
;
454 self = self.in_binder(&sig
, |mut cx
, sig
| {
455 if sig
.unsafety
== hir
::Unsafety
::Unsafe
{
460 Abi
::C { unwind: false }
=> cx
.push("KC"),
463 let name
= abi
.name();
464 if name
.contains('
-'
) {
465 cx
.push_ident(&name
.replace('
-'
, "_"));
471 for &ty
in sig
.inputs() {
478 sig
.output().print(cx
)
482 ty
::Dynamic(predicates
, r
, kind
) => {
483 self.push(match kind
{
485 // FIXME(dyn-star): need to update v0 mangling docs
488 self = self.print_dyn_existential(predicates
)?
;
489 self = r
.print(self)?
;
492 ty
::GeneratorWitness(_
) => bug
!("symbol_names: unexpected `GeneratorWitness`"),
495 // Only cache types that do not refer to an enclosing
496 // binder (which would change depending on context).
497 if !ty
.has_escaping_bound_vars() {
498 self.types
.insert(ty
, start
);
503 fn print_dyn_existential(
505 predicates
: &'tcx ty
::List
<ty
::Binder
<'tcx
, ty
::ExistentialPredicate
<'tcx
>>>,
506 ) -> Result
<Self::DynExistential
, Self::Error
> {
507 // Okay, so this is a bit tricky. Imagine we have a trait object like
508 // `dyn for<'a> Foo<'a, Bar = &'a ()>`. When we mangle this, the
509 // output looks really close to the syntax, where the `Bar = &'a ()` bit
510 // is under the same binders (`['a]`) as the `Foo<'a>` bit. However, we
511 // actually desugar these into two separate `ExistentialPredicate`s. We
512 // can't enter/exit the "binder scope" twice though, because then we
513 // would mangle the binders twice. (Also, side note, we merging these
514 // two is kind of difficult, because of potential HRTBs in the Projection
517 // Also worth mentioning: imagine that we instead had
518 // `dyn for<'a> Foo<'a, Bar = &'a ()> + Send`. In this case, `Send` is
519 // under the same binders as `Foo`. Currently, this doesn't matter,
520 // because only *auto traits* are allowed other than the principal trait
521 // and all auto traits don't have any generics. Two things could
522 // make this not an "okay" mangling:
523 // 1) Instead of mangling only *used*
524 // bound vars, we want to mangle *all* bound vars (`for<'b> Send` is a
525 // valid trait predicate);
526 // 2) We allow multiple "principal" traits in the future, or at least
527 // allow in any form another trait predicate that can take generics.
529 // Here we assume that predicates have the following structure:
530 // [<Trait> [{<Projection>}]] [{<Auto>}]
531 // Since any predicates after the first one shouldn't change the binders,
532 // just put them all in the binders of the first.
533 self = self.in_binder(&predicates
[0], |mut cx
, _
| {
534 for predicate
in predicates
.iter() {
535 // It would be nice to be able to validate bound vars here, but
536 // projections can actually include bound vars from super traits
537 // because of HRTBs (only in the `Self` type). Also, auto traits
538 // could have different bound vars *anyways*.
539 match predicate
.as_ref().skip_binder() {
540 ty
::ExistentialPredicate
::Trait(trait_ref
) => {
541 // Use a type that can't appear in defaults of type parameters.
542 let dummy_self
= cx
.tcx
.mk_ty_infer(ty
::FreshTy(0));
543 let trait_ref
= trait_ref
.with_self_ty(cx
.tcx
, dummy_self
);
544 cx
= cx
.print_def_path(trait_ref
.def_id
, trait_ref
.substs
)?
;
546 ty
::ExistentialPredicate
::Projection(projection
) => {
547 let name
= cx
.tcx
.associated_item(projection
.item_def_id
).name
;
549 cx
.push_ident(name
.as_str());
550 cx
= match projection
.term
.unpack() {
551 ty
::TermKind
::Ty(ty
) => ty
.print(cx
),
552 ty
::TermKind
::Const(c
) => c
.print(cx
),
555 ty
::ExistentialPredicate
::AutoTrait(def_id
) => {
556 cx
= cx
.print_def_path(*def_id
, &[])?
;
567 fn print_const(mut self, ct
: ty
::Const
<'tcx
>) -> Result
<Self::Const
, Self::Error
> {
568 // We only mangle a typed value if the const can be evaluated.
569 let ct
= ct
.eval(self.tcx
, ty
::ParamEnv
::reveal_all());
571 ty
::ConstKind
::Value(_
) => {}
573 // Placeholders (should be demangled as `_`).
574 // NOTE(eddyb) despite `Unevaluated` having a `DefId` (and therefore
575 // a path), even for it we still need to encode a placeholder, as
576 // the path could refer back to e.g. an `impl` using the constant.
577 ty
::ConstKind
::Unevaluated(_
)
578 | ty
::ConstKind
::Param(_
)
579 | ty
::ConstKind
::Infer(_
)
580 | ty
::ConstKind
::Bound(..)
581 | ty
::ConstKind
::Placeholder(_
)
582 | ty
::ConstKind
::Error(_
) => {
583 // Never cached (single-character).
589 if let Some(&i
) = self.consts
.get(&ct
) {
590 return self.print_backref(i
);
593 let start
= self.out
.len();
597 ty
::Uint(_
) | ty
::Int(_
) | ty
::Bool
| ty
::Char
=> {
598 self = ty
.print(self)?
;
600 let mut bits
= ct
.eval_bits(self.tcx
, ty
::ParamEnv
::reveal_all(), ty
);
602 // Negative integer values are mangled using `n` as a "sign prefix".
603 if let ty
::Int(ity
) = ty
.kind() {
605 Integer
::from_int_ty(&self.tcx
, *ity
).size().sign_extend(bits
) as i128
;
609 bits
= val
.unsigned_abs();
612 let _
= write
!(self.out
, "{:x}_", bits
);
615 // FIXME(valtrees): Remove the special case for `str`
616 // here and fully support unsized constants.
617 ty
::Ref(_
, inner_ty
, mutbl
) => {
618 self.push(match mutbl
{
619 hir
::Mutability
::Not
=> "R",
620 hir
::Mutability
::Mut
=> "Q",
623 match inner_ty
.kind() {
624 ty
::Str
if *mutbl
== hir
::Mutability
::Not
=> {
626 ty
::ConstKind
::Value(valtree
) => {
628 valtree
.try_to_raw_bytes(self.tcx(), ty
).unwrap_or_else(|| {
630 "expected to get raw bytes from valtree {:?} for type {:}",
634 let s
= std
::str::from_utf8(slice
).expect("non utf8 str from miri");
638 // FIXME(eddyb) use a specialized hex-encoding loop.
639 for byte
in s
.bytes() {
640 let _
= write
!(self.out
, "{:02x}", byte
);
647 bug
!("symbol_names: unsupported `&str` constant: {:?}", ct
);
655 .expect("tried to dereference on non-ptr type")
657 let dereferenced_const
=
658 self.tcx
.mk_const(ty
::ConstS { kind: ct.kind(), ty: pointee_ty }
);
659 self = dereferenced_const
.print(self)?
;
664 ty
::Array(..) | ty
::Tuple(..) | ty
::Adt(..) | ty
::Slice(_
) => {
665 let contents
= self.tcx
.destructure_const(ct
);
666 let fields
= contents
.fields
.iter().copied();
668 let print_field_list
= |mut this
: Self| {
669 for field
in fields
.clone() {
670 this
= field
.print(this
)?
;
676 match *ct
.ty().kind() {
677 ty
::Array(..) | ty
::Slice(_
) => {
679 self = print_field_list(self)?
;
683 self = print_field_list(self)?
;
685 ty
::Adt(def
, substs
) => {
687 contents
.variant
.expect("destructed const of adt without variant idx");
688 let variant_def
= &def
.variant(variant_idx
);
691 self = self.print_def_path(variant_def
.def_id
, substs
)?
;
693 match variant_def
.ctor_kind
{
699 self = print_field_list(self)?
;
701 CtorKind
::Fictive
=> {
703 for (field_def
, field
) in iter
::zip(&variant_def
.fields
, fields
) {
704 // HACK(eddyb) this mimics `path_append`,
705 // instead of simply using `field_def.ident`,
706 // just to be able to handle disambiguators.
707 let disambiguated_field
=
708 self.tcx
.def_key(field_def
.did
).disambiguated_data
;
709 let field_name
= disambiguated_field
.data
.get_opt_name();
710 self.push_disambiguator(
711 disambiguated_field
.disambiguator
as u64,
713 self.push_ident(field_name
.unwrap_or(kw
::Empty
).as_str());
715 self = field
.print(self)?
;
725 bug
!("symbol_names: unsupported constant of type `{}` ({:?})", ct
.ty(), ct
);
729 // Only cache consts that do not refer to an enclosing
730 // binder (which would change depending on context).
731 if !ct
.has_escaping_bound_vars() {
732 self.consts
.insert(ct
, start
);
737 fn path_crate(self, cnum
: CrateNum
) -> Result
<Self::Path
, Self::Error
> {
739 let stable_crate_id
= self.tcx
.def_path_hash(cnum
.as_def_id()).stable_crate_id();
740 self.push_disambiguator(stable_crate_id
.to_u64());
741 let name
= self.tcx
.crate_name(cnum
);
742 self.push_ident(name
.as_str());
749 trait_ref
: Option
<ty
::TraitRef
<'tcx
>>,
750 ) -> Result
<Self::Path
, Self::Error
> {
751 assert
!(trait_ref
.is_some());
752 let trait_ref
= trait_ref
.unwrap();
755 self = self_ty
.print(self)?
;
756 self.print_def_path(trait_ref
.def_id
, trait_ref
.substs
)
761 _
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
762 _
: &DisambiguatedDefPathData
,
764 _
: Option
<ty
::TraitRef
<'tcx
>>,
765 ) -> Result
<Self::Path
, Self::Error
> {
766 // Inlined into `print_impl_path`
772 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
773 disambiguated_data
: &DisambiguatedDefPathData
,
774 ) -> Result
<Self::Path
, Self::Error
> {
775 let ns
= match disambiguated_data
.data
{
776 // Extern block segments can be skipped, names from extern blocks
777 // are effectively living in their parent modules.
778 DefPathData
::ForeignMod
=> return print_prefix(self),
780 // Uppercase categories are more stable than lowercase ones.
781 DefPathData
::TypeNs(_
) => 't'
,
782 DefPathData
::ValueNs(_
) => 'v'
,
783 DefPathData
::ClosureExpr
=> 'C'
,
784 DefPathData
::Ctor
=> 'c'
,
785 DefPathData
::AnonConst
=> 'k'
,
786 DefPathData
::ImplTrait
=> 'i'
,
788 // These should never show up as `path_append` arguments.
789 DefPathData
::CrateRoot
791 | DefPathData
::GlobalAsm
793 | DefPathData
::MacroNs(_
)
794 | DefPathData
::LifetimeNs(_
) => {
795 bug
!("symbol_names: unexpected DefPathData: {:?}", disambiguated_data
.data
)
799 let name
= disambiguated_data
.data
.get_opt_name();
804 disambiguated_data
.disambiguator
as u64,
805 name
.unwrap_or(kw
::Empty
).as_str(),
809 fn path_generic_args(
811 print_prefix
: impl FnOnce(Self) -> Result
<Self::Path
, Self::Error
>,
812 args
: &[GenericArg
<'tcx
>],
813 ) -> Result
<Self::Path
, Self::Error
> {
814 // Don't print any regions if they're all erased.
815 let print_regions
= args
.iter().any(|arg
| match arg
.unpack() {
816 GenericArgKind
::Lifetime(r
) => !r
.is_erased(),
819 let args
= args
.iter().cloned().filter(|arg
| match arg
.unpack() {
820 GenericArgKind
::Lifetime(_
) => print_regions
,
824 if args
.clone().next().is_none() {
825 return print_prefix(self);
829 self = print_prefix(self)?
;
832 GenericArgKind
::Lifetime(lt
) => {
833 self = lt
.print(self)?
;
835 GenericArgKind
::Type(ty
) => {
836 self = ty
.print(self)?
;
838 GenericArgKind
::Const(c
) => {
840 self = c
.print(self)?
;