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android / toolchain / rustc / b1d328019a485dc2e58d5dc46556067c927ec9f2 / . / compiler / rustc_middle / src / ty / print / pretty.rs
blob: 7f2e81a71a93d16cd773eeb221339fa8eeca15df [file] [log] [blame]
use crate::mir::interpret::{AllocRange, GlobalAlloc, Pointer, Provenance, Scalar};
use crate::ty::subst::{GenericArg, GenericArgKind, Subst};
use crate::ty::{
self, ConstInt, DefIdTree, ParamConst, ScalarInt, Term, Ty, TyCtxt, TypeFoldable,
TypeSuperFoldable, TypeSuperVisitable, TypeVisitable,
};
use rustc_apfloat::ieee::{Double, Single};
use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
use rustc_data_structures::sso::SsoHashSet;
use rustc_hir as hir;
use rustc_hir::def::{self, CtorKind, DefKind, Namespace};
use rustc_hir::def_id::{DefId, DefIdSet, CRATE_DEF_ID, LOCAL_CRATE};
use rustc_hir::definitions::{DefPathData, DefPathDataName, DisambiguatedDefPathData};
use rustc_session::config::TrimmedDefPaths;
use rustc_session::cstore::{ExternCrate, ExternCrateSource};
use rustc_span::symbol::{kw, Ident, Symbol};
use rustc_target::abi::Size;
use rustc_target::spec::abi::Abi;
use std::cell::Cell;
use std::char;
use std::collections::BTreeMap;
use std::convert::TryFrom;
use std::fmt::{self, Write as _};
use std::iter;
use std::ops::{ControlFlow, Deref, DerefMut};
// `pretty` is a separate module only for organization.
use super::*;
macro_rules! p {
(@$lit:literal) => {
write!(scoped_cx!(), $lit)?
};
(@write($($data:expr),+)) => {
write!(scoped_cx!(), $($data),+)?
};
(@print($x:expr)) => {
scoped_cx!() = $x.print(scoped_cx!())?
};
(@$method:ident($($arg:expr),*)) => {
scoped_cx!() = scoped_cx!().$method($($arg),*)?
};
($($elem:tt $(($($args:tt)*))?),+) => {{
$(p!(@ $elem $(($($args)*))?);)+
}};
}
macro_rules! define_scoped_cx {
($cx:ident) => {
#[allow(unused_macros)]
macro_rules! scoped_cx {
() => {
$cx
};
}
};
}
thread_local! {
static FORCE_IMPL_FILENAME_LINE: Cell<bool> = const { Cell::new(false) };
static SHOULD_PREFIX_WITH_CRATE: Cell<bool> = const { Cell::new(false) };
static NO_TRIMMED_PATH: Cell<bool> = const { Cell::new(false) };
static NO_QUERIES: Cell<bool> = const { Cell::new(false) };
static NO_VISIBLE_PATH: Cell<bool> = const { Cell::new(false) };
}
macro_rules! define_helper {
($($(#[$a:meta])* fn $name:ident($helper:ident, $tl:ident);)+) => {
$(
#[must_use]
pub struct $helper(bool);
impl $helper {
pub fn new() -> $helper {
$helper($tl.with(|c| c.replace(true)))
}
}
$(#[$a])*
pub macro $name($e:expr) {
{
let _guard = $helper::new();
$e
}
}
impl Drop for $helper {
fn drop(&mut self) {
$tl.with(|c| c.set(self.0))
}
}
)+
}
}
define_helper!(
/// Avoids running any queries during any prints that occur
/// during the closure. This may alter the appearance of some
/// types (e.g. forcing verbose printing for opaque types).
/// This method is used during some queries (e.g. `explicit_item_bounds`
/// for opaque types), to ensure that any debug printing that
/// occurs during the query computation does not end up recursively
/// calling the same query.
fn with_no_queries(NoQueriesGuard, NO_QUERIES);
/// Force us to name impls with just the filename/line number. We
/// normally try to use types. But at some points, notably while printing
/// cycle errors, this can result in extra or suboptimal error output,
/// so this variable disables that check.
fn with_forced_impl_filename_line(ForcedImplGuard, FORCE_IMPL_FILENAME_LINE);
/// Adds the `crate::` prefix to paths where appropriate.
fn with_crate_prefix(CratePrefixGuard, SHOULD_PREFIX_WITH_CRATE);
/// Prevent path trimming if it is turned on. Path trimming affects `Display` impl
/// of various rustc types, for example `std::vec::Vec` would be trimmed to `Vec`,
/// if no other `Vec` is found.
fn with_no_trimmed_paths(NoTrimmedGuard, NO_TRIMMED_PATH);
/// Prevent selection of visible paths. `Display` impl of DefId will prefer
/// visible (public) reexports of types as paths.
fn with_no_visible_paths(NoVisibleGuard, NO_VISIBLE_PATH);
);
/// The "region highlights" are used to control region printing during
/// specific error messages. When a "region highlight" is enabled, it
/// gives an alternate way to print specific regions. For now, we
/// always print those regions using a number, so something like "`'0`".
///
/// Regions not selected by the region highlight mode are presently
/// unaffected.
#[derive(Copy, Clone)]
pub struct RegionHighlightMode<'tcx> {
tcx: TyCtxt<'tcx>,
/// If enabled, when we see the selected region, use "`'N`"
/// instead of the ordinary behavior.
highlight_regions: [Option<(ty::Region<'tcx>, usize)>; 3],
/// If enabled, when printing a "free region" that originated from
/// the given `ty::BoundRegionKind`, print it as "`'1`". Free regions that would ordinarily
/// have names print as normal.
///
/// This is used when you have a signature like `fn foo(x: &u32,
/// y: &'a u32)` and we want to give a name to the region of the
/// reference `x`.
highlight_bound_region: Option<(ty::BoundRegionKind, usize)>,
}
impl<'tcx> RegionHighlightMode<'tcx> {
pub fn new(tcx: TyCtxt<'tcx>) -> Self {
Self {
tcx,
highlight_regions: Default::default(),
highlight_bound_region: Default::default(),
}
}
/// If `region` and `number` are both `Some`, invokes
/// `highlighting_region`.
pub fn maybe_highlighting_region(
&mut self,
region: Option<ty::Region<'tcx>>,
number: Option<usize>,
) {
if let Some(k) = region {
if let Some(n) = number {
self.highlighting_region(k, n);
}
}
}
/// Highlights the region inference variable `vid` as `'N`.
pub fn highlighting_region(&mut self, region: ty::Region<'tcx>, number: usize) {
let num_slots = self.highlight_regions.len();
let first_avail_slot =
self.highlight_regions.iter_mut().find(|s| s.is_none()).unwrap_or_else(|| {
bug!("can only highlight {} placeholders at a time", num_slots,)
});
*first_avail_slot = Some((region, number));
}
/// Convenience wrapper for `highlighting_region`.
pub fn highlighting_region_vid(&mut self, vid: ty::RegionVid, number: usize) {
self.highlighting_region(self.tcx.mk_region(ty::ReVar(vid)), number)
}
/// Returns `Some(n)` with the number to use for the given region, if any.
fn region_highlighted(&self, region: ty::Region<'tcx>) -> Option<usize> {
self.highlight_regions.iter().find_map(|h| match h {
Some((r, n)) if *r == region => Some(*n),
_ => None,
})
}
/// Highlight the given bound region.
/// We can only highlight one bound region at a time. See
/// the field `highlight_bound_region` for more detailed notes.
pub fn highlighting_bound_region(&mut self, br: ty::BoundRegionKind, number: usize) {
assert!(self.highlight_bound_region.is_none());
self.highlight_bound_region = Some((br, number));
}
}
/// Trait for printers that pretty-print using `fmt::Write` to the printer.
pub trait PrettyPrinter<'tcx>:
Printer<
'tcx,
Error = fmt::Error,
Path = Self,
Region = Self,
Type = Self,
DynExistential = Self,
Const = Self,
> + fmt::Write
{
/// Like `print_def_path` but for value paths.
fn print_value_path(
self,
def_id: DefId,
substs: &'tcx [GenericArg<'tcx>],
) -> Result<Self::Path, Self::Error> {
self.print_def_path(def_id, substs)
}
fn in_binder<T>(self, value: &ty::Binder<'tcx, T>) -> Result<Self, Self::Error>
where
T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>,
{
value.as_ref().skip_binder().print(self)
}
fn wrap_binder<T, F: FnOnce(&T, Self) -> Result<Self, fmt::Error>>(
self,
value: &ty::Binder<'tcx, T>,
f: F,
) -> Result<Self, Self::Error>
where
T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>,
{
f(value.as_ref().skip_binder(), self)
}
/// Prints comma-separated elements.
fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, Self::Error>
where
T: Print<'tcx, Self, Output = Self, Error = Self::Error>,
{
if let Some(first) = elems.next() {
self = first.print(self)?;
for elem in elems {
self.write_str(", ")?;
self = elem.print(self)?;
}
}
Ok(self)
}
/// Prints `{f: t}` or `{f as t}` depending on the `cast` argument
fn typed_value(
mut self,
f: impl FnOnce(Self) -> Result<Self, Self::Error>,
t: impl FnOnce(Self) -> Result<Self, Self::Error>,
conversion: &str,
) -> Result<Self::Const, Self::Error> {
self.write_str("{")?;
self = f(self)?;
self.write_str(conversion)?;
self = t(self)?;
self.write_str("}")?;
Ok(self)
}
/// Prints `<...>` around what `f` prints.
fn generic_delimiters(
self,
f: impl FnOnce(Self) -> Result<Self, Self::Error>,
) -> Result<Self, Self::Error>;
/// Returns `true` if the region should be printed in
/// optional positions, e.g., `&'a T` or `dyn Tr + 'b`.
/// This is typically the case for all non-`'_` regions.
fn should_print_region(&self, region: ty::Region<'tcx>) -> bool;
// Defaults (should not be overridden):
/// If possible, this returns a global path resolving to `def_id` that is visible
/// from at least one local module, and returns `true`. If the crate defining `def_id` is
/// declared with an `extern crate`, the path is guaranteed to use the `extern crate`.
fn try_print_visible_def_path(self, def_id: DefId) -> Result<(Self, bool), Self::Error> {
if NO_VISIBLE_PATH.with(|flag| flag.get()) {
return Ok((self, false));
}
let mut callers = Vec::new();
self.try_print_visible_def_path_recur(def_id, &mut callers)
}
/// Try to see if this path can be trimmed to a unique symbol name.
fn try_print_trimmed_def_path(
mut self,
def_id: DefId,
) -> Result<(Self::Path, bool), Self::Error> {
if !self.tcx().sess.opts.unstable_opts.trim_diagnostic_paths
|| matches!(self.tcx().sess.opts.trimmed_def_paths, TrimmedDefPaths::Never)
|| NO_TRIMMED_PATH.with(|flag| flag.get())
|| SHOULD_PREFIX_WITH_CRATE.with(|flag| flag.get())
{
return Ok((self, false));
}
match self.tcx().trimmed_def_paths(()).get(&def_id) {
None => Ok((self, false)),
Some(symbol) => {
self.write_str(symbol.as_str())?;
Ok((self, true))
}
}
}
/// Does the work of `try_print_visible_def_path`, building the
/// full definition path recursively before attempting to
/// post-process it into the valid and visible version that
/// accounts for re-exports.
///
/// This method should only be called by itself or
/// `try_print_visible_def_path`.
///
/// `callers` is a chain of visible_parent's leading to `def_id`,
/// to support cycle detection during recursion.
///
/// This method returns false if we can't print the visible path, so
/// `print_def_path` can fall back on the item's real definition path.
fn try_print_visible_def_path_recur(
mut self,
def_id: DefId,
callers: &mut Vec<DefId>,
) -> Result<(Self, bool), Self::Error> {
define_scoped_cx!(self);
debug!("try_print_visible_def_path: def_id={:?}", def_id);
// If `def_id` is a direct or injected extern crate, return the
// path to the crate followed by the path to the item within the crate.
if let Some(cnum) = def_id.as_crate_root() {
if cnum == LOCAL_CRATE {
return Ok((self.path_crate(cnum)?, true));
}
// In local mode, when we encounter a crate other than
// LOCAL_CRATE, execution proceeds in one of two ways:
//
// 1. For a direct dependency, where user added an
// `extern crate` manually, we put the `extern
// crate` as the parent. So you wind up with
// something relative to the current crate.
// 2. For an extern inferred from a path or an indirect crate,
// where there is no explicit `extern crate`, we just prepend
// the crate name.
match self.tcx().extern_crate(def_id) {
Some(&ExternCrate { src, dependency_of, span, .. }) => match (src, dependency_of) {
(ExternCrateSource::Extern(def_id), LOCAL_CRATE) => {
// NOTE(eddyb) the only reason `span` might be dummy,
// that we're aware of, is that it's the `std`/`core`
// `extern crate` injected by default.
// FIXME(eddyb) find something better to key this on,
// or avoid ending up with `ExternCrateSource::Extern`,
// for the injected `std`/`core`.
if span.is_dummy() {
return Ok((self.path_crate(cnum)?, true));
}
// Disable `try_print_trimmed_def_path` behavior within
// the `print_def_path` call, to avoid infinite recursion
// in cases where the `extern crate foo` has non-trivial
// parents, e.g. it's nested in `impl foo::Trait for Bar`
// (see also issues #55779 and #87932).
self = with_no_visible_paths!(self.print_def_path(def_id, &[])?);
return Ok((self, true));
}
(ExternCrateSource::Path, LOCAL_CRATE) => {
return Ok((self.path_crate(cnum)?, true));
}
_ => {}
},
None => {
return Ok((self.path_crate(cnum)?, true));
}
}
}
if def_id.is_local() {
return Ok((self, false));
}
let visible_parent_map = self.tcx().visible_parent_map(());
let mut cur_def_key = self.tcx().def_key(def_id);
debug!("try_print_visible_def_path: cur_def_key={:?}", cur_def_key);
// For a constructor, we want the name of its parent rather than <unnamed>.
if let DefPathData::Ctor = cur_def_key.disambiguated_data.data {
let parent = DefId {
krate: def_id.krate,
index: cur_def_key
.parent
.expect("`DefPathData::Ctor` / `VariantData` missing a parent"),
};
cur_def_key = self.tcx().def_key(parent);
}
let Some(visible_parent) = visible_parent_map.get(&def_id).cloned() else {
return Ok((self, false));
};
let actual_parent = self.tcx().opt_parent(def_id);
debug!(
"try_print_visible_def_path: visible_parent={:?} actual_parent={:?}",
visible_parent, actual_parent,
);
let mut data = cur_def_key.disambiguated_data.data;
debug!(
"try_print_visible_def_path: data={:?} visible_parent={:?} actual_parent={:?}",
data, visible_parent, actual_parent,
);
match data {
// In order to output a path that could actually be imported (valid and visible),
// we need to handle re-exports correctly.
//
// For example, take `std::os::unix::process::CommandExt`, this trait is actually
// defined at `std::sys::unix::ext::process::CommandExt` (at time of writing).
//
// `std::os::unix` reexports the contents of `std::sys::unix::ext`. `std::sys` is
// private so the "true" path to `CommandExt` isn't accessible.
//
// In this case, the `visible_parent_map` will look something like this:
//
// (child) -> (parent)
// `std::sys::unix::ext::process::CommandExt` -> `std::sys::unix::ext::process`
// `std::sys::unix::ext::process` -> `std::sys::unix::ext`
// `std::sys::unix::ext` -> `std::os`
//
// This is correct, as the visible parent of `std::sys::unix::ext` is in fact
// `std::os`.
//
// When printing the path to `CommandExt` and looking at the `cur_def_key` that
// corresponds to `std::sys::unix::ext`, we would normally print `ext` and then go
// to the parent - resulting in a mangled path like
// `std::os::ext::process::CommandExt`.
//
// Instead, we must detect that there was a re-export and instead print `unix`
// (which is the name `std::sys::unix::ext` was re-exported as in `std::os`). To
// do this, we compare the parent of `std::sys::unix::ext` (`std::sys::unix`) with
// the visible parent (`std::os`). If these do not match, then we iterate over
// the children of the visible parent (as was done when computing
// `visible_parent_map`), looking for the specific child we currently have and then
// have access to the re-exported name.
DefPathData::TypeNs(ref mut name) if Some(visible_parent) != actual_parent => {
// Item might be re-exported several times, but filter for the one
// that's public and whose identifier isn't `_`.
let reexport = self
.tcx()
.module_children(visible_parent)
.iter()
.filter(|child| child.res.opt_def_id() == Some(def_id))
.find(|child| child.vis.is_public() && child.ident.name != kw::Underscore)
.map(|child| child.ident.name);
if let Some(new_name) = reexport {
*name = new_name;
} else {
// There is no name that is public and isn't `_`, so bail.
return Ok((self, false));
}
}
// Re-exported `extern crate` (#43189).
DefPathData::CrateRoot => {
data = DefPathData::TypeNs(self.tcx().crate_name(def_id.krate));
}
_ => {}
}
debug!("try_print_visible_def_path: data={:?}", data);
if callers.contains(&visible_parent) {
return Ok((self, false));
}
callers.push(visible_parent);
// HACK(eddyb) this bypasses `path_append`'s prefix printing to avoid
// knowing ahead of time whether the entire path will succeed or not.
// To support printers that do not implement `PrettyPrinter`, a `Vec` or
// linked list on the stack would need to be built, before any printing.
match self.try_print_visible_def_path_recur(visible_parent, callers)? {
(cx, false) => return Ok((cx, false)),
(cx, true) => self = cx,
}
callers.pop();
Ok((self.path_append(Ok, &DisambiguatedDefPathData { data, disambiguator: 0 })?, true))
}
fn pretty_path_qualified(
self,
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
if trait_ref.is_none() {
// Inherent impls. Try to print `Foo::bar` for an inherent
// impl on `Foo`, but fallback to `<Foo>::bar` if self-type is
// anything other than a simple path.
match self_ty.kind() {
ty::Adt(..)
| ty::Foreign(_)
| ty::Bool
| ty::Char
| ty::Str
| ty::Int(_)
| ty::Uint(_)
| ty::Float(_) => {
return self_ty.print(self);
}
_ => {}
}
}
self.generic_delimiters(|mut cx| {
define_scoped_cx!(cx);
p!(print(self_ty));
if let Some(trait_ref) = trait_ref {
p!(" as ", print(trait_ref.print_only_trait_path()));
}
Ok(cx)
})
}
fn pretty_path_append_impl(
mut self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
self = print_prefix(self)?;
self.generic_delimiters(|mut cx| {
define_scoped_cx!(cx);
p!("impl ");
if let Some(trait_ref) = trait_ref {
p!(print(trait_ref.print_only_trait_path()), " for ");
}
p!(print(self_ty));
Ok(cx)
})
}
fn pretty_print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
define_scoped_cx!(self);
match *ty.kind() {
ty::Bool => p!("bool"),
ty::Char => p!("char"),
ty::Int(t) => p!(write("{}", t.name_str())),
ty::Uint(t) => p!(write("{}", t.name_str())),
ty::Float(t) => p!(write("{}", t.name_str())),
ty::RawPtr(ref tm) => {
p!(write(
"*{} ",
match tm.mutbl {
hir::Mutability::Mut => "mut",
hir::Mutability::Not => "const",
}
));
p!(print(tm.ty))
}
ty::Ref(r, ty, mutbl) => {
p!("&");
if self.should_print_region(r) {
p!(print(r), " ");
}
p!(print(ty::TypeAndMut { ty, mutbl }))
}
ty::Never => p!("!"),
ty::Tuple(ref tys) => {
p!("(", comma_sep(tys.iter()));
if tys.len() == 1 {
p!(",");
}
p!(")")
}
ty::FnDef(def_id, substs) => {
let sig = self.tcx().bound_fn_sig(def_id).subst(self.tcx(), substs);
p!(print(sig), " {{", print_value_path(def_id, substs), "}}");
}
ty::FnPtr(ref bare_fn) => p!(print(bare_fn)),
ty::Infer(infer_ty) => {
let verbose = self.tcx().sess.verbose();
if let ty::TyVar(ty_vid) = infer_ty {
if let Some(name) = self.ty_infer_name(ty_vid) {
p!(write("{}", name))
} else {
if verbose {
p!(write("{:?}", infer_ty))
} else {
p!(write("{}", infer_ty))
}
}
} else {
if verbose { p!(write("{:?}", infer_ty)) } else { p!(write("{}", infer_ty)) }
}
}
ty::Error(_) => p!("[type error]"),
ty::Param(ref param_ty) => p!(print(param_ty)),
ty::Bound(debruijn, bound_ty) => match bound_ty.kind {
ty::BoundTyKind::Anon => self.pretty_print_bound_var(debruijn, bound_ty.var)?,
ty::BoundTyKind::Param(p) => p!(write("{}", p)),
},
ty::Adt(def, substs) => {
p!(print_def_path(def.did(), substs));
}
ty::Dynamic(data, r) => {
let print_r = self.should_print_region(r);
if print_r {
p!("(");
}
p!("dyn ", print(data));
if print_r {
p!(" + ", print(r), ")");
}
}
ty::Foreign(def_id) => {
p!(print_def_path(def_id, &[]));
}
ty::Projection(ref data) => p!(print(data)),
ty::Placeholder(placeholder) => p!(write("Placeholder({:?})", placeholder)),
ty::Opaque(def_id, substs) => {
// FIXME(eddyb) print this with `print_def_path`.
// We use verbose printing in 'NO_QUERIES' mode, to
// avoid needing to call `predicates_of`. This should
// only affect certain debug messages (e.g. messages printed
// from `rustc_middle::ty` during the computation of `tcx.predicates_of`),
// and should have no effect on any compiler output.
if self.tcx().sess.verbose() || NO_QUERIES.with(|q| q.get()) {
p!(write("Opaque({:?}, {:?})", def_id, substs));
return Ok(self);
}
let parent = self.tcx().parent(def_id);
match self.tcx().def_kind(parent) {
DefKind::TyAlias | DefKind::AssocTy => {
if let ty::Opaque(d, _) = *self.tcx().type_of(parent).kind() {
if d == def_id {
// If the type alias directly starts with the `impl` of the
// opaque type we're printing, then skip the `::{opaque#1}`.
p!(print_def_path(parent, substs));
return Ok(self);
}
}
// Complex opaque type, e.g. `type Foo = (i32, impl Debug);`
p!(print_def_path(def_id, substs));
return Ok(self);
}
_ => return self.pretty_print_opaque_impl_type(def_id, substs),
}
}
ty::Str => p!("str"),
ty::Generator(did, substs, movability) => {
p!(write("["));
match movability {
hir::Movability::Movable => {}
hir::Movability::Static => p!("static "),
}
if !self.tcx().sess.verbose() {
p!("generator");
// FIXME(eddyb) should use `def_span`.
if let Some(did) = did.as_local() {
let span = self.tcx().def_span(did);
p!(write(
"@{}",
// This may end up in stderr diagnostics but it may also be emitted
// into MIR. Hence we use the remapped path if available
self.tcx().sess.source_map().span_to_embeddable_string(span)
));
} else {
p!(write("@"), print_def_path(did, substs));
}
} else {
p!(print_def_path(did, substs));
p!(" upvar_tys=(");
if !substs.as_generator().is_valid() {
p!("unavailable");
} else {
self = self.comma_sep(substs.as_generator().upvar_tys())?;
}
p!(")");
if substs.as_generator().is_valid() {
p!(" ", print(substs.as_generator().witness()));
}
}
p!("]")
}
ty::GeneratorWitness(types) => {
p!(in_binder(&types));
}
ty::Closure(did, substs) => {
p!(write("["));
if !self.tcx().sess.verbose() {
p!(write("closure"));
// FIXME(eddyb) should use `def_span`.
if let Some(did) = did.as_local() {
if self.tcx().sess.opts.unstable_opts.span_free_formats {
p!("@", print_def_path(did.to_def_id(), substs));
} else {
let span = self.tcx().def_span(did);
p!(write(
"@{}",
// This may end up in stderr diagnostics but it may also be emitted
// into MIR. Hence we use the remapped path if available
self.tcx().sess.source_map().span_to_embeddable_string(span)
));
}
} else {
p!(write("@"), print_def_path(did, substs));
}
} else {
p!(print_def_path(did, substs));
if !substs.as_closure().is_valid() {
p!(" closure_substs=(unavailable)");
p!(write(" substs={:?}", substs));
} else {
p!(" closure_kind_ty=", print(substs.as_closure().kind_ty()));
p!(
" closure_sig_as_fn_ptr_ty=",
print(substs.as_closure().sig_as_fn_ptr_ty())
);
p!(" upvar_tys=(");
self = self.comma_sep(substs.as_closure().upvar_tys())?;
p!(")");
}
}
p!("]");
}
ty::Array(ty, sz) => {
p!("[", print(ty), "; ");
if self.tcx().sess.verbose() {
p!(write("{:?}", sz));
} else if let ty::ConstKind::Unevaluated(..) = sz.kind() {
// Do not try to evaluate unevaluated constants. If we are const evaluating an
// array length anon const, rustc will (with debug assertions) print the
// constant's path. Which will end up here again.
p!("_");
} else if let Some(n) = sz.kind().try_to_bits(self.tcx().data_layout.pointer_size) {
p!(write("{}", n));
} else if let ty::ConstKind::Param(param) = sz.kind() {
p!(print(param));
} else {
p!("_");
}
p!("]")
}
ty::Slice(ty) => p!("[", print(ty), "]"),
}
Ok(self)
}
fn pretty_print_opaque_impl_type(
mut self,
def_id: DefId,
substs: &'tcx ty::List<ty::GenericArg<'tcx>>,
) -> Result<Self::Type, Self::Error> {
let tcx = self.tcx();
// Grab the "TraitA + TraitB" from `impl TraitA + TraitB`,
// by looking up the projections associated with the def_id.
let bounds = tcx.bound_explicit_item_bounds(def_id);
let mut traits = FxIndexMap::default();
let mut fn_traits = FxIndexMap::default();
let mut is_sized = false;
for predicate in bounds.transpose_iter().map(|e| e.map_bound(|(p, _)| *p)) {
let predicate = predicate.subst(tcx, substs);
let bound_predicate = predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(pred) => {
let trait_ref = bound_predicate.rebind(pred.trait_ref);
// Don't print + Sized, but rather + ?Sized if absent.
if Some(trait_ref.def_id()) == tcx.lang_items().sized_trait() {
is_sized = true;
continue;
}
self.insert_trait_and_projection(trait_ref, None, &mut traits, &mut fn_traits);
}
ty::PredicateKind::Projection(pred) => {
let proj_ref = bound_predicate.rebind(pred);
let trait_ref = proj_ref.required_poly_trait_ref(tcx);
// Projection type entry -- the def-id for naming, and the ty.
let proj_ty = (proj_ref.projection_def_id(), proj_ref.term());
self.insert_trait_and_projection(
trait_ref,
Some(proj_ty),
&mut traits,
&mut fn_traits,
);
}
_ => {}
}
}
write!(self, "impl ")?;
let mut first = true;
// Insert parenthesis around (Fn(A, B) -> C) if the opaque ty has more than one other trait
let paren_needed = fn_traits.len() > 1 || traits.len() > 0 || !is_sized;
for (fn_once_trait_ref, entry) in fn_traits {
write!(self, "{}", if first { "" } else { " + " })?;
write!(self, "{}", if paren_needed { "(" } else { "" })?;
self = self.wrap_binder(&fn_once_trait_ref, |trait_ref, mut cx| {
define_scoped_cx!(cx);
// Get the (single) generic ty (the args) of this FnOnce trait ref.
let generics = tcx.generics_of(trait_ref.def_id);
let args = generics.own_substs_no_defaults(tcx, trait_ref.substs);
match (entry.return_ty, args[0].expect_ty()) {
// We can only print `impl Fn() -> ()` if we have a tuple of args and we recorded
// a return type.
(Some(return_ty), arg_tys) if matches!(arg_tys.kind(), ty::Tuple(_)) => {
let name = if entry.fn_trait_ref.is_some() {
"Fn"
} else if entry.fn_mut_trait_ref.is_some() {
"FnMut"
} else {
"FnOnce"
};
p!(write("{}(", name));
for (idx, ty) in arg_tys.tuple_fields().iter().enumerate() {
if idx > 0 {
p!(", ");
}
p!(print(ty));
}
p!(")");
if let Term::Ty(ty) = return_ty.skip_binder() {
if !ty.is_unit() {
p!(" -> ", print(return_ty));
}
}
p!(write("{}", if paren_needed { ")" } else { "" }));
first = false;
}
// If we got here, we can't print as a `impl Fn(A, B) -> C`. Just record the
// trait_refs we collected in the OpaqueFnEntry as normal trait refs.
_ => {
if entry.has_fn_once {
traits.entry(fn_once_trait_ref).or_default().extend(
// Group the return ty with its def id, if we had one.
entry
.return_ty
.map(|ty| (tcx.lang_items().fn_once_output().unwrap(), ty)),
);
}
if let Some(trait_ref) = entry.fn_mut_trait_ref {
traits.entry(trait_ref).or_default();
}
if let Some(trait_ref) = entry.fn_trait_ref {
traits.entry(trait_ref).or_default();
}
}
}
Ok(cx)
})?;
}
// Print the rest of the trait types (that aren't Fn* family of traits)
for (trait_ref, assoc_items) in traits {
write!(self, "{}", if first { "" } else { " + " })?;
self = self.wrap_binder(&trait_ref, |trait_ref, mut cx| {
define_scoped_cx!(cx);
p!(print(trait_ref.print_only_trait_name()));
let generics = tcx.generics_of(trait_ref.def_id);
let args = generics.own_substs_no_defaults(tcx, trait_ref.substs);
if !args.is_empty() || !assoc_items.is_empty() {
let mut first = true;
for ty in args {
if first {
p!("<");
first = false;
} else {
p!(", ");
}
p!(print(ty));
}
for (assoc_item_def_id, term) in assoc_items {
// Skip printing `<[generator@] as Generator<_>>::Return` from async blocks,
// unless we can find out what generator return type it comes from.
let term = if let Some(ty) = term.skip_binder().ty()
&& let ty::Projection(ty::ProjectionTy { item_def_id, substs }) = ty.kind()
&& Some(*item_def_id) == tcx.lang_items().generator_return()
{
if let ty::Generator(_, substs, _) = substs.type_at(0).kind() {
let return_ty = substs.as_generator().return_ty();
if !return_ty.is_ty_infer() {
return_ty.into()
} else {
continue;
}
} else {
continue;
}
} else {
term.skip_binder()
};
if first {
p!("<");
first = false;
} else {
p!(", ");
}
p!(write("{} = ", tcx.associated_item(assoc_item_def_id).name));
match term {
Term::Ty(ty) => {
p!(print(ty))
}
Term::Const(c) => {
p!(print(c));
}
};
}
if !first {
p!(">");
}
}
first = false;
Ok(cx)
})?;
}
if !is_sized {
write!(self, "{}?Sized", if first { "" } else { " + " })?;
} else if first {
write!(self, "Sized")?;
}
Ok(self)
}
/// Insert the trait ref and optionally a projection type associated with it into either the
/// traits map or fn_traits map, depending on if the trait is in the Fn* family of traits.
fn insert_trait_and_projection(
&mut self,
trait_ref: ty::PolyTraitRef<'tcx>,
proj_ty: Option<(DefId, ty::Binder<'tcx, Term<'tcx>>)>,
traits: &mut FxIndexMap<
ty::PolyTraitRef<'tcx>,
FxIndexMap<DefId, ty::Binder<'tcx, Term<'tcx>>>,
>,
fn_traits: &mut FxIndexMap<ty::PolyTraitRef<'tcx>, OpaqueFnEntry<'tcx>>,
) {
let trait_def_id = trait_ref.def_id();
// If our trait_ref is FnOnce or any of its children, project it onto the parent FnOnce
// super-trait ref and record it there.
if let Some(fn_once_trait) = self.tcx().lang_items().fn_once_trait() {
// If we have a FnOnce, then insert it into
if trait_def_id == fn_once_trait {
let entry = fn_traits.entry(trait_ref).or_default();
// Optionally insert the return_ty as well.
if let Some((_, ty)) = proj_ty {
entry.return_ty = Some(ty);
}
entry.has_fn_once = true;
return;
} else if Some(trait_def_id) == self.tcx().lang_items().fn_mut_trait() {
let super_trait_ref = crate::traits::util::supertraits(self.tcx(), trait_ref)
.find(|super_trait_ref| super_trait_ref.def_id() == fn_once_trait)
.unwrap();
fn_traits.entry(super_trait_ref).or_default().fn_mut_trait_ref = Some(trait_ref);
return;
} else if Some(trait_def_id) == self.tcx().lang_items().fn_trait() {
let super_trait_ref = crate::traits::util::supertraits(self.tcx(), trait_ref)
.find(|super_trait_ref| super_trait_ref.def_id() == fn_once_trait)
.unwrap();
fn_traits.entry(super_trait_ref).or_default().fn_trait_ref = Some(trait_ref);
return;
}
}
// Otherwise, just group our traits and projection types.
traits.entry(trait_ref).or_default().extend(proj_ty);
}
fn pretty_print_bound_var(
&mut self,
debruijn: ty::DebruijnIndex,
var: ty::BoundVar,
) -> Result<(), Self::Error> {
if debruijn == ty::INNERMOST {
write!(self, "^{}", var.index())
} else {
write!(self, "^{}_{}", debruijn.index(), var.index())
}
}
fn ty_infer_name(&self, _: ty::TyVid) -> Option<Symbol> {
None
}
fn const_infer_name(&self, _: ty::ConstVid<'tcx>) -> Option<Symbol> {
None
}
fn pretty_print_dyn_existential(
mut self,
predicates: &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>,
) -> Result<Self::DynExistential, Self::Error> {
// Generate the main trait ref, including associated types.
let mut first = true;
if let Some(principal) = predicates.principal() {
self = self.wrap_binder(&principal, |principal, mut cx| {
define_scoped_cx!(cx);
p!(print_def_path(principal.def_id, &[]));
let mut resugared = false;
// Special-case `Fn(...) -> ...` and re-sugar it.
let fn_trait_kind = cx.tcx().fn_trait_kind_from_lang_item(principal.def_id);
if !cx.tcx().sess.verbose() && fn_trait_kind.is_some() {
if let ty::Tuple(tys) = principal.substs.type_at(0).kind() {
let mut projections = predicates.projection_bounds();
if let (Some(proj), None) = (projections.next(), projections.next()) {
p!(pretty_fn_sig(
tys,
false,
proj.skip_binder().term.ty().expect("Return type was a const")
));
resugared = true;
}
}
}
// HACK(eddyb) this duplicates `FmtPrinter`'s `path_generic_args`,
// in order to place the projections inside the `<...>`.
if !resugared {
// Use a type that can't appear in defaults of type parameters.
let dummy_cx = cx.tcx().mk_ty_infer(ty::FreshTy(0));
let principal = principal.with_self_ty(cx.tcx(), dummy_cx);
let args = cx
.tcx()
.generics_of(principal.def_id)
.own_substs_no_defaults(cx.tcx(), principal.substs);
// Don't print `'_` if there's no unerased regions.
let print_regions = args.iter().any(|arg| match arg.unpack() {
GenericArgKind::Lifetime(r) => !r.is_erased(),
_ => false,
});
let mut args = args.iter().cloned().filter(|arg| match arg.unpack() {
GenericArgKind::Lifetime(_) => print_regions,
_ => true,
});
let mut projections = predicates.projection_bounds();
let arg0 = args.next();
let projection0 = projections.next();
if arg0.is_some() || projection0.is_some() {
let args = arg0.into_iter().chain(args);
let projections = projection0.into_iter().chain(projections);
p!(generic_delimiters(|mut cx| {
cx = cx.comma_sep(args)?;
if arg0.is_some() && projection0.is_some() {
write!(cx, ", ")?;
}
cx.comma_sep(projections)
}));
}
}
Ok(cx)
})?;
first = false;
}
define_scoped_cx!(self);
// Builtin bounds.
// FIXME(eddyb) avoid printing twice (needed to ensure
// that the auto traits are sorted *and* printed via cx).
let mut auto_traits: Vec<_> = predicates.auto_traits().collect();
// The auto traits come ordered by `DefPathHash`. While
// `DefPathHash` is *stable* in the sense that it depends on
// neither the host nor the phase of the moon, it depends
// "pseudorandomly" on the compiler version and the target.
//
// To avoid causing instabilities in compiletest
// output, sort the auto-traits alphabetically.
auto_traits.sort_by_cached_key(|did| self.tcx().def_path_str(*did));
for def_id in auto_traits {
if !first {
p!(" + ");
}
first = false;
p!(print_def_path(def_id, &[]));
}
Ok(self)
}
fn pretty_fn_sig(
mut self,
inputs: &[Ty<'tcx>],
c_variadic: bool,
output: Ty<'tcx>,
) -> Result<Self, Self::Error> {
define_scoped_cx!(self);
p!("(", comma_sep(inputs.iter().copied()));
if c_variadic {
if !inputs.is_empty() {
p!(", ");
}
p!("...");
}
p!(")");
if !output.is_unit() {
p!(" -> ", print(output));
}
Ok(self)
}
fn pretty_print_const(
mut self,
ct: ty::Const<'tcx>,
print_ty: bool,
) -> Result<Self::Const, Self::Error> {
define_scoped_cx!(self);
if self.tcx().sess.verbose() {
p!(write("Const({:?}: {:?})", ct.kind(), ct.ty()));
return Ok(self);
}
macro_rules! print_underscore {
() => {{
if print_ty {
self = self.typed_value(
|mut this| {
write!(this, "_")?;
Ok(this)
},
|this| this.print_type(ct.ty()),
": ",
)?;
} else {
write!(self, "_")?;
}
}};
}
match ct.kind() {
ty::ConstKind::Unevaluated(ty::Unevaluated {
def,
substs,
promoted: Some(promoted),
}) => {
p!(print_value_path(def.did, substs));
p!(write("::{:?}", promoted));
}
ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted: None }) => {
match self.tcx().def_kind(def.did) {
DefKind::Static(..) | DefKind::Const | DefKind::AssocConst => {
p!(print_value_path(def.did, substs))
}
_ => {
if def.is_local() {
let span = self.tcx().def_span(def.did);
if let Ok(snip) = self.tcx().sess.source_map().span_to_snippet(span) {
p!(write("{}", snip))
} else {
print_underscore!()
}
} else {
print_underscore!()
}
}
}
}
ty::ConstKind::Infer(infer_ct) => {
match infer_ct {
ty::InferConst::Var(ct_vid)
if let Some(name) = self.const_infer_name(ct_vid) =>
p!(write("{}", name)),
_ => print_underscore!(),
}
}
ty::ConstKind::Param(ParamConst { name, .. }) => p!(write("{}", name)),
ty::ConstKind::Value(value) => {
return self.pretty_print_const_valtree(value, ct.ty(), print_ty);
}
ty::ConstKind::Bound(debruijn, bound_var) => {
self.pretty_print_bound_var(debruijn, bound_var)?
}
ty::ConstKind::Placeholder(placeholder) => p!(write("Placeholder({:?})", placeholder)),
ty::ConstKind::Error(_) => p!("[const error]"),
};
Ok(self)
}
fn pretty_print_const_scalar(
self,
scalar: Scalar,
ty: Ty<'tcx>,
print_ty: bool,
) -> Result<Self::Const, Self::Error> {
match scalar {
Scalar::Ptr(ptr, _size) => self.pretty_print_const_scalar_ptr(ptr, ty, print_ty),
Scalar::Int(int) => self.pretty_print_const_scalar_int(int, ty, print_ty),
}
}
fn pretty_print_const_scalar_ptr(
mut self,
ptr: Pointer,
ty: Ty<'tcx>,
print_ty: bool,
) -> Result<Self::Const, Self::Error> {
define_scoped_cx!(self);
let (alloc_id, offset) = ptr.into_parts();
match ty.kind() {
// Byte strings (&[u8; N])
ty::Ref(_, inner, _) => {
if let ty::Array(elem, len) = inner.kind() {
if let ty::Uint(ty::UintTy::U8) = elem.kind() {
if let ty::ConstKind::Value(ty::ValTree::Leaf(int)) = len.kind() {
match self.tcx().try_get_global_alloc(alloc_id) {
Some(GlobalAlloc::Memory(alloc)) => {
let len = int.assert_bits(self.tcx().data_layout.pointer_size);
let range =
AllocRange { start: offset, size: Size::from_bytes(len) };
if let Ok(byte_str) =
alloc.inner().get_bytes(&self.tcx(), range)
{
p!(pretty_print_byte_str(byte_str))
} else {
p!("<too short allocation>")
}
}
// FIXME: for statics, vtables, and functions, we could in principle print more detail.
Some(GlobalAlloc::Static(def_id)) => {
p!(write("<static({:?})>", def_id))
}
Some(GlobalAlloc::Function(_)) => p!("<function>"),
Some(GlobalAlloc::VTable(..)) => p!("<vtable>"),
None => p!("<dangling pointer>"),
}
return Ok(self);
}
}
}
}
ty::FnPtr(_) => {
// FIXME: We should probably have a helper method to share code with the "Byte strings"
// printing above (which also has to handle pointers to all sorts of things).
if let Some(GlobalAlloc::Function(instance)) =
self.tcx().try_get_global_alloc(alloc_id)
{
self = self.typed_value(
|this| this.print_value_path(instance.def_id(), instance.substs),
|this| this.print_type(ty),
" as ",
)?;
return Ok(self);
}
}
_ => {}
}
// Any pointer values not covered by a branch above
self = self.pretty_print_const_pointer(ptr, ty, print_ty)?;
Ok(self)
}
fn pretty_print_const_scalar_int(
mut self,
int: ScalarInt,
ty: Ty<'tcx>,
print_ty: bool,
) -> Result<Self::Const, Self::Error> {
define_scoped_cx!(self);
match ty.kind() {
// Bool
ty::Bool if int == ScalarInt::FALSE => p!("false"),
ty::Bool if int == ScalarInt::TRUE => p!("true"),
// Float
ty::Float(ty::FloatTy::F32) => {
p!(write("{}f32", Single::try_from(int).unwrap()))
}
ty::Float(ty::FloatTy::F64) => {
p!(write("{}f64", Double::try_from(int).unwrap()))
}
// Int
ty::Uint(_) | ty::Int(_) => {
let int =
ConstInt::new(int, matches!(ty.kind(), ty::Int(_)), ty.is_ptr_sized_integral());
if print_ty { p!(write("{:#?}", int)) } else { p!(write("{:?}", int)) }
}
// Char
ty::Char if char::try_from(int).is_ok() => {
p!(write("{:?}", char::try_from(int).unwrap()))
}
// Pointer types
ty::Ref(..) | ty::RawPtr(_) | ty::FnPtr(_) => {
let data = int.assert_bits(self.tcx().data_layout.pointer_size);
self = self.typed_value(
|mut this| {
write!(this, "0x{:x}", data)?;
Ok(this)
},
|this| this.print_type(ty),
" as ",
)?;
}
// Nontrivial types with scalar bit representation
_ => {
let print = |mut this: Self| {
if int.size() == Size::ZERO {
write!(this, "transmute(())")?;
} else {
write!(this, "transmute(0x{:x})", int)?;
}
Ok(this)
};
self = if print_ty {
self.typed_value(print, |this| this.print_type(ty), ": ")?
} else {
print(self)?
};
}
}
Ok(self)
}
/// This is overridden for MIR printing because we only want to hide alloc ids from users, not
/// from MIR where it is actually useful.
fn pretty_print_const_pointer<Prov: Provenance>(
mut self,
_: Pointer<Prov>,
ty: Ty<'tcx>,
print_ty: bool,
) -> Result<Self::Const, Self::Error> {
if print_ty {
self.typed_value(
|mut this| {
this.write_str("&_")?;
Ok(this)
},
|this| this.print_type(ty),
": ",
)
} else {
self.write_str("&_")?;
Ok(self)
}
}
fn pretty_print_byte_str(mut self, byte_str: &'tcx [u8]) -> Result<Self::Const, Self::Error> {
define_scoped_cx!(self);
p!("b\"");
for &c in byte_str {
for e in std::ascii::escape_default(c) {
self.write_char(e as char)?;
}
}
p!("\"");
Ok(self)
}
fn pretty_print_const_valtree(
mut self,
valtree: ty::ValTree<'tcx>,
ty: Ty<'tcx>,
print_ty: bool,
) -> Result<Self::Const, Self::Error> {
define_scoped_cx!(self);
if self.tcx().sess.verbose() {
p!(write("ValTree({:?}: ", valtree), print(ty), ")");
return Ok(self);
}
let u8_type = self.tcx().types.u8;
match (valtree, ty.kind()) {
(ty::ValTree::Branch(_), ty::Ref(_, inner_ty, _)) => match inner_ty.kind() {
ty::Slice(t) if *t == u8_type => {
let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| {
bug!(
"expected to convert valtree {:?} to raw bytes for type {:?}",
valtree,
t
)
});
return self.pretty_print_byte_str(bytes);
}
ty::Str => {
let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| {
bug!("expected to convert valtree to raw bytes for type {:?}", ty)
});
p!(write("{:?}", String::from_utf8_lossy(bytes)));
return Ok(self);
}
_ => {
p!("&");
p!(pretty_print_const_valtree(valtree, *inner_ty, print_ty));
return Ok(self);
}
},
(ty::ValTree::Branch(_), ty::Array(t, _)) if *t == u8_type => {
let bytes = valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| {
bug!("expected to convert valtree to raw bytes for type {:?}", t)
});
p!("*");
p!(pretty_print_byte_str(bytes));
return Ok(self);
}
// Aggregates, printed as array/tuple/struct/variant construction syntax.
(ty::ValTree::Branch(_), ty::Array(..) | ty::Tuple(..) | ty::Adt(..)) => {
let contents =
self.tcx().destructure_const(ty::Const::from_value(self.tcx(), valtree, ty));
let fields = contents.fields.iter().copied();
match *ty.kind() {
ty::Array(..) => {
p!("[", comma_sep(fields), "]");
}
ty::Tuple(..) => {
p!("(", comma_sep(fields));
if contents.fields.len() == 1 {
p!(",");
}
p!(")");
}
ty::Adt(def, _) if def.variants().is_empty() => {
self = self.typed_value(
|mut this| {
write!(this, "unreachable()")?;
Ok(this)
},
|this| this.print_type(ty),
": ",
)?;
}
ty::Adt(def, substs) => {
let variant_idx =
contents.variant.expect("destructed const of adt without variant idx");
let variant_def = &def.variant(variant_idx);
p!(print_value_path(variant_def.def_id, substs));
match variant_def.ctor_kind {
CtorKind::Const => {}
CtorKind::Fn => {
p!("(", comma_sep(fields), ")");
}
CtorKind::Fictive => {
p!(" {{ ");
let mut first = true;
for (field_def, field) in iter::zip(&variant_def.fields, fields) {
if !first {
p!(", ");
}
p!(write("{}: ", field_def.name), print(field));
first = false;
}
p!(" }}");
}
}
}
_ => unreachable!(),
}
return Ok(self);
}
(ty::ValTree::Leaf(leaf), _) => {
return self.pretty_print_const_scalar_int(leaf, ty, print_ty);
}
// FIXME(oli-obk): also pretty print arrays and other aggregate constants by reading
// their fields instead of just dumping the memory.
_ => {}
}
// fallback
if valtree == ty::ValTree::zst() {
p!(write("<ZST>"));
} else {
p!(write("{:?}", valtree));
}
if print_ty {
p!(": ", print(ty));
}
Ok(self)
}
}
// HACK(eddyb) boxed to avoid moving around a large struct by-value.
pub struct FmtPrinter<'a, 'tcx>(Box<FmtPrinterData<'a, 'tcx>>);
pub struct FmtPrinterData<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
fmt: String,
empty_path: bool,
in_value: bool,
pub print_alloc_ids: bool,
used_region_names: FxHashSet<Symbol>,
region_index: usize,
binder_depth: usize,
printed_type_count: usize,
pub region_highlight_mode: RegionHighlightMode<'tcx>,
pub ty_infer_name_resolver: Option<Box<dyn Fn(ty::TyVid) -> Option<Symbol> + 'a>>,
pub const_infer_name_resolver: Option<Box<dyn Fn(ty::ConstVid<'tcx>) -> Option<Symbol> + 'a>>,
}
impl<'a, 'tcx> Deref for FmtPrinter<'a, 'tcx> {
type Target = FmtPrinterData<'a, 'tcx>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl DerefMut for FmtPrinter<'_, '_> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
impl<'a, 'tcx> FmtPrinter<'a, 'tcx> {
pub fn new(tcx: TyCtxt<'tcx>, ns: Namespace) -> Self {
FmtPrinter(Box::new(FmtPrinterData {
tcx,
// Estimated reasonable capacity to allocate upfront based on a few
// benchmarks.
fmt: String::with_capacity(64),
empty_path: false,
in_value: ns == Namespace::ValueNS,
print_alloc_ids: false,
used_region_names: Default::default(),
region_index: 0,
binder_depth: 0,
printed_type_count: 0,
region_highlight_mode: RegionHighlightMode::new(tcx),
ty_infer_name_resolver: None,
const_infer_name_resolver: None,
}))
}
pub fn into_buffer(self) -> String {
self.0.fmt
}
}
// HACK(eddyb) get rid of `def_path_str` and/or pass `Namespace` explicitly always
// (but also some things just print a `DefId` generally so maybe we need this?)
fn guess_def_namespace(tcx: TyCtxt<'_>, def_id: DefId) -> Namespace {
match tcx.def_key(def_id).disambiguated_data.data {
DefPathData::TypeNs(..) | DefPathData::CrateRoot | DefPathData::ImplTrait => {
Namespace::TypeNS
}
DefPathData::ValueNs(..)
| DefPathData::AnonConst
| DefPathData::ClosureExpr
| DefPathData::Ctor => Namespace::ValueNS,
DefPathData::MacroNs(..) => Namespace::MacroNS,
_ => Namespace::TypeNS,
}
}
impl<'t> TyCtxt<'t> {
/// Returns a string identifying this `DefId`. This string is
/// suitable for user output.
pub fn def_path_str(self, def_id: DefId) -> String {
self.def_path_str_with_substs(def_id, &[])
}
pub fn def_path_str_with_substs(self, def_id: DefId, substs: &'t [GenericArg<'t>]) -> String {
let ns = guess_def_namespace(self, def_id);
debug!("def_path_str: def_id={:?}, ns={:?}", def_id, ns);
FmtPrinter::new(self, ns).print_def_path(def_id, substs).unwrap().into_buffer()
}
}
impl fmt::Write for FmtPrinter<'_, '_> {
fn write_str(&mut self, s: &str) -> fmt::Result {
self.fmt.push_str(s);
Ok(())
}
}
impl<'tcx> Printer<'tcx> for FmtPrinter<'_, 'tcx> {
type Error = fmt::Error;
type Path = Self;
type Region = Self;
type Type = Self;
type DynExistential = Self;
type Const = Self;
fn tcx<'a>(&'a self) -> TyCtxt<'tcx> {
self.tcx
}
fn print_def_path(
mut self,
def_id: DefId,
substs: &'tcx [GenericArg<'tcx>],
) -> Result<Self::Path, Self::Error> {
define_scoped_cx!(self);
if substs.is_empty() {
match self.try_print_trimmed_def_path(def_id)? {
(cx, true) => return Ok(cx),
(cx, false) => self = cx,
}
match self.try_print_visible_def_path(def_id)? {
(cx, true) => return Ok(cx),
(cx, false) => self = cx,
}
}
let key = self.tcx.def_key(def_id);
if let DefPathData::Impl = key.disambiguated_data.data {
// Always use types for non-local impls, where types are always
// available, and filename/line-number is mostly uninteresting.
let use_types = !def_id.is_local() || {
// Otherwise, use filename/line-number if forced.
let force_no_types = FORCE_IMPL_FILENAME_LINE.with(|f| f.get());
!force_no_types
};
if !use_types {
// If no type info is available, fall back to
// pretty printing some span information. This should
// only occur very early in the compiler pipeline.
let parent_def_id = DefId { index: key.parent.unwrap(), ..def_id };
let span = self.tcx.def_span(def_id);
self = self.print_def_path(parent_def_id, &[])?;
// HACK(eddyb) copy of `path_append` to avoid
// constructing a `DisambiguatedDefPathData`.
if !self.empty_path {
write!(self, "::")?;
}
write!(
self,
"<impl at {}>",
// This may end up in stderr diagnostics but it may also be emitted
// into MIR. Hence we use the remapped path if available
self.tcx.sess.source_map().span_to_embeddable_string(span)
)?;
self.empty_path = false;
return Ok(self);
}
}
self.default_print_def_path(def_id, substs)
}
fn print_region(self, region: ty::Region<'tcx>) -> Result<Self::Region, Self::Error> {
self.pretty_print_region(region)
}
fn print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
let type_length_limit = self.tcx.type_length_limit();
if type_length_limit.value_within_limit(self.printed_type_count) {
self.printed_type_count += 1;
self.pretty_print_type(ty)
} else {
write!(self, "...")?;
Ok(self)
}
}
fn print_dyn_existential(
self,
predicates: &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>,
) -> Result<Self::DynExistential, Self::Error> {
self.pretty_print_dyn_existential(predicates)
}
fn print_const(self, ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
self.pretty_print_const(ct, false)
}
fn path_crate(mut self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
self.empty_path = true;
if cnum == LOCAL_CRATE {
if self.tcx.sess.rust_2018() {
// We add the `crate::` keyword on Rust 2018, only when desired.
if SHOULD_PREFIX_WITH_CRATE.with(|flag| flag.get()) {
write!(self, "{}", kw::Crate)?;
self.empty_path = false;
}
}
} else {
write!(self, "{}", self.tcx.crate_name(cnum))?;
self.empty_path = false;
}
Ok(self)
}
fn path_qualified(
mut self,
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
self = self.pretty_path_qualified(self_ty, trait_ref)?;
self.empty_path = false;
Ok(self)
}
fn path_append_impl(
mut self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
_disambiguated_data: &DisambiguatedDefPathData,
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
self = self.pretty_path_append_impl(
|mut cx| {
cx = print_prefix(cx)?;
if !cx.empty_path {
write!(cx, "::")?;
}
Ok(cx)
},
self_ty,
trait_ref,
)?;
self.empty_path = false;
Ok(self)
}
fn path_append(
mut self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
disambiguated_data: &DisambiguatedDefPathData,
) -> Result<Self::Path, Self::Error> {
self = print_prefix(self)?;
// Skip `::{{extern}}` blocks and `::{{constructor}}` on tuple/unit structs.
if let DefPathData::ForeignMod | DefPathData::Ctor = disambiguated_data.data {
return Ok(self);
}
let name = disambiguated_data.data.name();
if !self.empty_path {
write!(self, "::")?;
}
if let DefPathDataName::Named(name) = name {
if Ident::with_dummy_span(name).is_raw_guess() {
write!(self, "r#")?;
}
}
let verbose = self.tcx.sess.verbose();
disambiguated_data.fmt_maybe_verbose(&mut self, verbose)?;
self.empty_path = false;
Ok(self)
}
fn path_generic_args(
mut self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
args: &[GenericArg<'tcx>],
) -> Result<Self::Path, Self::Error> {
self = print_prefix(self)?;
// Don't print `'_` if there's no unerased regions.
let print_regions = self.tcx.sess.verbose()
|| args.iter().any(|arg| match arg.unpack() {
GenericArgKind::Lifetime(r) => !r.is_erased(),
_ => false,
});
let args = args.iter().cloned().filter(|arg| match arg.unpack() {
GenericArgKind::Lifetime(_) => print_regions,
_ => true,
});
if args.clone().next().is_some() {
if self.in_value {
write!(self, "::")?;
}
self.generic_delimiters(|cx| cx.comma_sep(args))
} else {
Ok(self)
}
}
}
impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> {
fn ty_infer_name(&self, id: ty::TyVid) -> Option<Symbol> {
self.0.ty_infer_name_resolver.as_ref().and_then(|func| func(id))
}
fn const_infer_name(&self, id: ty::ConstVid<'tcx>) -> Option<Symbol> {
self.0.const_infer_name_resolver.as_ref().and_then(|func| func(id))
}
fn print_value_path(
mut self,
def_id: DefId,
substs: &'tcx [GenericArg<'tcx>],
) -> Result<Self::Path, Self::Error> {
let was_in_value = std::mem::replace(&mut self.in_value, true);
self = self.print_def_path(def_id, substs)?;
self.in_value = was_in_value;
Ok(self)
}
fn in_binder<T>(self, value: &ty::Binder<'tcx, T>) -> Result<Self, Self::Error>
where
T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>,
{
self.pretty_in_binder(value)
}
fn wrap_binder<T, C: FnOnce(&T, Self) -> Result<Self, Self::Error>>(
self,
value: &ty::Binder<'tcx, T>,
f: C,
) -> Result<Self, Self::Error>
where
T: Print<'tcx, Self, Output = Self, Error = Self::Error> + TypeFoldable<'tcx>,
{
self.pretty_wrap_binder(value, f)
}
fn typed_value(
mut self,
f: impl FnOnce(Self) -> Result<Self, Self::Error>,
t: impl FnOnce(Self) -> Result<Self, Self::Error>,
conversion: &str,
) -> Result<Self::Const, Self::Error> {
self.write_str("{")?;
self = f(self)?;
self.write_str(conversion)?;
let was_in_value = std::mem::replace(&mut self.in_value, false);
self = t(self)?;
self.in_value = was_in_value;
self.write_str("}")?;
Ok(self)
}
fn generic_delimiters(
mut self,
f: impl FnOnce(Self) -> Result<Self, Self::Error>,
) -> Result<Self, Self::Error> {
write!(self, "<")?;
let was_in_value = std::mem::replace(&mut self.in_value, false);
let mut inner = f(self)?;
inner.in_value = was_in_value;
write!(inner, ">")?;
Ok(inner)
}
fn should_print_region(&self, region: ty::Region<'tcx>) -> bool {
let highlight = self.region_highlight_mode;
if highlight.region_highlighted(region).is_some() {
return true;
}
if self.tcx.sess.verbose() {
return true;
}
let identify_regions = self.tcx.sess.opts.unstable_opts.identify_regions;
match *region {
ty::ReEarlyBound(ref data) => {
data.name != kw::Empty && data.name != kw::UnderscoreLifetime
}
ty::ReLateBound(_, ty::BoundRegion { kind: br, .. })
| ty::ReFree(ty::FreeRegion { bound_region: br, .. })
| ty::RePlaceholder(ty::Placeholder { name: br, .. }) => {
if let ty::BrNamed(_, name) = br {
if name != kw::Empty && name != kw::UnderscoreLifetime {
return true;
}
}
if let Some((region, _)) = highlight.highlight_bound_region {
if br == region {
return true;
}
}
false
}
ty::ReVar(_) if identify_regions => true,
ty::ReVar(_) | ty::ReErased => false,
ty::ReStatic | ty::ReEmpty(_) => true,
}
}
fn pretty_print_const_pointer<Prov: Provenance>(
self,
p: Pointer<Prov>,
ty: Ty<'tcx>,
print_ty: bool,
) -> Result<Self::Const, Self::Error> {
let print = |mut this: Self| {
define_scoped_cx!(this);
if this.print_alloc_ids {
p!(write("{:?}", p));
} else {
p!("&_");
}
Ok(this)
};
if print_ty {
self.typed_value(print, |this| this.print_type(ty), ": ")
} else {
print(self)
}
}
}
// HACK(eddyb) limited to `FmtPrinter` because of `region_highlight_mode`.
impl<'tcx> FmtPrinter<'_, 'tcx> {
pub fn pretty_print_region(mut self, region: ty::Region<'tcx>) -> Result<Self, fmt::Error> {
define_scoped_cx!(self);
// Watch out for region highlights.
let highlight = self.region_highlight_mode;
if let Some(n) = highlight.region_highlighted(region) {
p!(write("'{}", n));
return Ok(self);
}
if self.tcx.sess.verbose() {
p!(write("{:?}", region));
return Ok(self);
}
let identify_regions = self.tcx.sess.opts.unstable_opts.identify_regions;
// These printouts are concise. They do not contain all the information
// the user might want to diagnose an error, but there is basically no way
// to fit that into a short string. Hence the recommendation to use
// `explain_region()` or `note_and_explain_region()`.
match *region {
ty::ReEarlyBound(ref data) => {
if data.name != kw::Empty {
p!(write("{}", data.name));
return Ok(self);
}
}
ty::ReLateBound(_, ty::BoundRegion { kind: br, .. })
| ty::ReFree(ty::FreeRegion { bound_region: br, .. })
| ty::RePlaceholder(ty::Placeholder { name: br, .. }) => {
if let ty::BrNamed(_, name) = br {
if name != kw::Empty && name != kw::UnderscoreLifetime {
p!(write("{}", name));
return Ok(self);
}
}
if let Some((region, counter)) = highlight.highlight_bound_region {
if br == region {
p!(write("'{}", counter));
return Ok(self);
}
}
}
ty::ReVar(region_vid) if identify_regions => {
p!(write("{:?}", region_vid));
return Ok(self);
}
ty::ReVar(_) => {}
ty::ReErased => {}
ty::ReStatic => {
p!("'static");
return Ok(self);
}
ty::ReEmpty(ty::UniverseIndex::ROOT) => {
p!("'<empty>");
return Ok(self);
}
ty::ReEmpty(ui) => {
p!(write("'<empty:{:?}>", ui));
return Ok(self);
}
}
p!("'_");
Ok(self)
}
}
/// Folds through bound vars and placeholders, naming them
struct RegionFolder<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
current_index: ty::DebruijnIndex,
region_map: BTreeMap<ty::BoundRegion, ty::Region<'tcx>>,
name: &'a mut (dyn FnMut(ty::BoundRegion) -> ty::Region<'tcx> + 'a),
}
impl<'a, 'tcx> ty::TypeFolder<'tcx> for RegionFolder<'a, 'tcx> {
fn tcx<'b>(&'b self) -> TyCtxt<'tcx> {
self.tcx
}
fn fold_binder<T: TypeFoldable<'tcx>>(
&mut self,
t: ty::Binder<'tcx, T>,
) -> ty::Binder<'tcx, T> {
self.current_index.shift_in(1);
let t = t.super_fold_with(self);
self.current_index.shift_out(1);
t
}
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
match *t.kind() {
_ if t.has_vars_bound_at_or_above(self.current_index) || t.has_placeholders() => {
return t.super_fold_with(self);
}
_ => {}
}
t
}
fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
let name = &mut self.name;
let region = match *r {
ty::ReLateBound(_, br) => *self.region_map.entry(br).or_insert_with(|| name(br)),
ty::RePlaceholder(ty::PlaceholderRegion { name: kind, .. }) => {
// If this is an anonymous placeholder, don't rename. Otherwise, in some
// async fns, we get a `for<'r> Send` bound
match kind {
ty::BrAnon(_) | ty::BrEnv => r,
_ => {
// Index doesn't matter, since this is just for naming and these never get bound
let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind };
*self.region_map.entry(br).or_insert_with(|| name(br))
}
}
}
_ => return r,
};
if let ty::ReLateBound(debruijn1, br) = *region {
assert_eq!(debruijn1, ty::INNERMOST);
self.tcx.mk_region(ty::ReLateBound(self.current_index, br))
} else {
region
}
}
}
// HACK(eddyb) limited to `FmtPrinter` because of `binder_depth`,
// `region_index` and `used_region_names`.
impl<'tcx> FmtPrinter<'_, 'tcx> {
pub fn name_all_regions<T>(
mut self,
value: &ty::Binder<'tcx, T>,
) -> Result<(Self, T, BTreeMap<ty::BoundRegion, ty::Region<'tcx>>), fmt::Error>
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)),
}
}
// 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);
}
let mut empty = true;
let mut start_or_continue = |cx: &mut Self, start: &str, cont: &str| {
let w = if empty {
empty = false;
start
} else {
cont
};
let _ = write!(cx, "{}", w);
};
let do_continue = |cx: &mut Self, cont: Symbol| {
let _ = write!(cx, "{}", cont);
};
define_scoped_cx!(self);
let mut region_index = self.region_index;
let mut next_name = |this: &Self| loop {
let name = name_by_region_index(region_index);
region_index += 1;
if !this.used_region_names.contains(&name) {
break name;
}
};
// If we want to print verbosely, then print *all* binders, even if they
// aren't named. Eventually, we might just want this as the default, but
// this is not *quite* right and changes the ordering of some output
// anyways.
let (new_value, map) = if self.tcx().sess.verbose() {
let regions: Vec<_> = value
.bound_vars()
.into_iter()
.map(|var| {
let ty::BoundVariableKind::Region(var) = var else {
// This doesn't really matter because it doesn't get used,
// it's just an empty value
return ty::BrAnon(0);
};
match var {
ty::BrAnon(_) | ty::BrEnv => {
start_or_continue(&mut self, "for<", ", ");
let name = next_name(&self);
do_continue(&mut self, name);
ty::BrNamed(CRATE_DEF_ID.to_def_id(), name)
}
ty::BrNamed(def_id, kw::UnderscoreLifetime) => {
start_or_continue(&mut self, "for<", ", ");
let name = next_name(&self);
do_continue(&mut self, name);
ty::BrNamed(def_id, name)
}
ty::BrNamed(def_id, name) => {
start_or_continue(&mut self, "for<", ", ");
do_continue(&mut self, name);
ty::BrNamed(def_id, name)
}
}
})
.collect();
start_or_continue(&mut self, "", "> ");
self.tcx.replace_late_bound_regions(value.clone(), |br| {
let kind = regions[br.var.as_usize()];
self.tcx.mk_region(ty::ReLateBound(
ty::INNERMOST,
ty::BoundRegion { var: br.var, kind },
))
})
} else {
let tcx = self.tcx;
let mut name = |br: ty::BoundRegion| {
start_or_continue(&mut self, "for<", ", ");
let kind = match br.kind {
ty::BrAnon(_) | ty::BrEnv => {
let name = next_name(&self);
do_continue(&mut self, name);
ty::BrNamed(CRATE_DEF_ID.to_def_id(), name)
}
ty::BrNamed(def_id, kw::UnderscoreLifetime) => {
let name = next_name(&self);
do_continue(&mut self, name);
ty::BrNamed(def_id, name)
}
ty::BrNamed(_, name) => {
do_continue(&mut self, name);
br.kind
}
};
tcx.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BoundRegion { var: br.var, kind }))
};
let mut folder = RegionFolder {
tcx,
current_index: ty::INNERMOST,
name: &mut name,
region_map: BTreeMap::new(),
};
let new_value = value.clone().skip_binder().fold_with(&mut folder);
let region_map = folder.region_map;
start_or_continue(&mut self, "", "> ");
(new_value, region_map)
};
self.binder_depth += 1;
self.region_index = region_index;
Ok((self, new_value, map))
}
pub fn pretty_in_binder<T>(self, value: &ty::Binder<'tcx, T>) -> Result<Self, fmt::Error>
where
T: Print<'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>,
{
let old_region_index = self.region_index;
let (new, new_value, _) = self.name_all_regions(value)?;
let mut inner = new_value.print(new)?;
inner.region_index = old_region_index;
inner.binder_depth -= 1;
Ok(inner)
}
pub fn pretty_wrap_binder<T, C: FnOnce(&T, Self) -> Result<Self, fmt::Error>>(
self,
value: &ty::Binder<'tcx, T>,
f: C,
) -> Result<Self, fmt::Error>
where
T: Print<'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>,
{
let old_region_index = self.region_index;
let (new, new_value, _) = self.name_all_regions(value)?;
let mut inner = f(&new_value, new)?;
inner.region_index = old_region_index;
inner.binder_depth -= 1;
Ok(inner)
}
fn prepare_late_bound_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>,
type_collector: SsoHashSet<Ty<'tcx>>,
}
impl<'tcx> ty::visit::TypeVisitor<'tcx> for LateBoundRegionNameCollector<'_, '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
{
self.used_region_names.insert(name);
}
r.super_visit_with(self)
}
// We collect types in order to prevent really large types from compiling for
// a really long time. See issue #83150 for why this is necessary.
fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
let not_previously_inserted = self.type_collector.insert(ty);
if not_previously_inserted {
ty.super_visit_with(self)
} else {
ControlFlow::CONTINUE
}
}
}
self.used_region_names.clear();
let mut collector = LateBoundRegionNameCollector {
used_region_names: &mut self.used_region_names,
type_collector: SsoHashSet::new(),
};
value.visit_with(&mut collector);
self.region_index = 0;
}
}
impl<'tcx, T, P: PrettyPrinter<'tcx>> Print<'tcx, P> for ty::Binder<'tcx, T>
where
T: Print<'tcx, P, Output = P, Error = P::Error> + TypeFoldable<'tcx>,
{
type Output = P;
type Error = P::Error;
fn print(&self, cx: P) -> Result<Self::Output, Self::Error> {
cx.in_binder(self)
}
}
impl<'tcx, T, U, P: PrettyPrinter<'tcx>> Print<'tcx, P> for ty::OutlivesPredicate<T, U>
where
T: Print<'tcx, P, Output = P, Error = P::Error>,
U: Print<'tcx, P, Output = P, Error = P::Error>,
{
type Output = P;
type Error = P::Error;
fn print(&self, mut cx: P) -> Result<Self::Output, Self::Error> {
define_scoped_cx!(cx);
p!(print(self.0), ": ", print(self.1));
Ok(cx)
}
}
macro_rules! forward_display_to_print {
($($ty:ty),+) => {
// Some of the $ty arguments may not actually use 'tcx
$(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
ty::tls::with(|tcx| {
let cx = tcx.lift(*self)
.expect("could not lift for printing")
.print(FmtPrinter::new(tcx, Namespace::TypeNS))?;
f.write_str(&cx.into_buffer())?;
Ok(())
})
}
})+
};
}
macro_rules! define_print_and_forward_display {
(($self:ident, $cx:ident): $($ty:ty $print:block)+) => {
$(impl<'tcx, P: PrettyPrinter<'tcx>> Print<'tcx, P> for $ty {
type Output = P;
type Error = fmt::Error;
fn print(&$self, $cx: P) -> Result<Self::Output, Self::Error> {
#[allow(unused_mut)]
let mut $cx = $cx;
define_scoped_cx!($cx);
let _: () = $print;
#[allow(unreachable_code)]
Ok($cx)
}
})+
forward_display_to_print!($($ty),+);
};
}
/// Wrapper type for `ty::TraitRef` which opts-in to pretty printing only
/// the trait path. That is, it will print `Trait<U>` instead of
/// `<T as Trait<U>>`.
#[derive(Copy, Clone, TypeFoldable, TypeVisitable, Lift)]
pub struct TraitRefPrintOnlyTraitPath<'tcx>(ty::TraitRef<'tcx>);
impl<'tcx> fmt::Debug for TraitRefPrintOnlyTraitPath<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(self, f)
}
}
/// Wrapper type for `ty::TraitRef` which opts-in to pretty printing only
/// the trait name. That is, it will print `Trait` instead of
/// `<T as Trait<U>>`.
#[derive(Copy, Clone, TypeFoldable, TypeVisitable, Lift)]
pub struct TraitRefPrintOnlyTraitName<'tcx>(ty::TraitRef<'tcx>);
impl<'tcx> fmt::Debug for TraitRefPrintOnlyTraitName<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(self, f)
}
}
impl<'tcx> ty::TraitRef<'tcx> {
pub fn print_only_trait_path(self) -> TraitRefPrintOnlyTraitPath<'tcx> {
TraitRefPrintOnlyTraitPath(self)
}
pub fn print_only_trait_name(self) -> TraitRefPrintOnlyTraitName<'tcx> {
TraitRefPrintOnlyTraitName(self)
}
}
impl<'tcx> ty::Binder<'tcx, ty::TraitRef<'tcx>> {
pub fn print_only_trait_path(self) -> ty::Binder<'tcx, TraitRefPrintOnlyTraitPath<'tcx>> {
self.map_bound(|tr| tr.print_only_trait_path())
}
}
#[derive(Copy, Clone, TypeFoldable, TypeVisitable, Lift)]
pub struct TraitPredPrintModifiersAndPath<'tcx>(ty::TraitPredicate<'tcx>);
impl<'tcx> fmt::Debug for TraitPredPrintModifiersAndPath<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(self, f)
}
}
impl<'tcx> ty::TraitPredicate<'tcx> {
pub fn print_modifiers_and_trait_path(self) -> TraitPredPrintModifiersAndPath<'tcx> {
TraitPredPrintModifiersAndPath(self)
}
}
impl<'tcx> ty::PolyTraitPredicate<'tcx> {
pub fn print_modifiers_and_trait_path(
self,
) -> ty::Binder<'tcx, TraitPredPrintModifiersAndPath<'tcx>> {
self.map_bound(TraitPredPrintModifiersAndPath)
}
}
forward_display_to_print! {
ty::Region<'tcx>,
Ty<'tcx>,
&'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>,
ty::Const<'tcx>,
// HACK(eddyb) these are exhaustive instead of generic,
// because `for<'tcx>` isn't possible yet.
ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>,
ty::Binder<'tcx, ty::TraitRef<'tcx>>,
ty::Binder<'tcx, ty::ExistentialTraitRef<'tcx>>,
ty::Binder<'tcx, TraitRefPrintOnlyTraitPath<'tcx>>,
ty::Binder<'tcx, TraitRefPrintOnlyTraitName<'tcx>>,
ty::Binder<'tcx, ty::FnSig<'tcx>>,
ty::Binder<'tcx, ty::TraitPredicate<'tcx>>,
ty::Binder<'tcx, TraitPredPrintModifiersAndPath<'tcx>>,
ty::Binder<'tcx, ty::SubtypePredicate<'tcx>>,
ty::Binder<'tcx, ty::ProjectionPredicate<'tcx>>,
ty::Binder<'tcx, ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>>,
ty::Binder<'tcx, ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>>,
ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>,
ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>
}
define_print_and_forward_display! {
(self, cx):
&'tcx ty::List<Ty<'tcx>> {
p!("{{", comma_sep(self.iter()), "}}")
}
ty::TypeAndMut<'tcx> {
p!(write("{}", self.mutbl.prefix_str()), print(self.ty))
}
ty::ExistentialTraitRef<'tcx> {
// Use a type that can't appear in defaults of type parameters.
let dummy_self = cx.tcx().mk_ty_infer(ty::FreshTy(0));
let trait_ref = self.with_self_ty(cx.tcx(), dummy_self);
p!(print(trait_ref.print_only_trait_path()))
}
ty::ExistentialProjection<'tcx> {
let name = cx.tcx().associated_item(self.item_def_id).name;
p!(write("{} = ", name), print(self.term))
}
ty::ExistentialPredicate<'tcx> {
match *self {
ty::ExistentialPredicate::Trait(x) => p!(print(x)),
ty::ExistentialPredicate::Projection(x) => p!(print(x)),
ty::ExistentialPredicate::AutoTrait(def_id) => {
p!(print_def_path(def_id, &[]));
}
}
}
ty::FnSig<'tcx> {
p!(write("{}", self.unsafety.prefix_str()));
if self.abi != Abi::Rust {
p!(write("extern {} ", self.abi));
}
p!("fn", pretty_fn_sig(self.inputs(), self.c_variadic, self.output()));
}
ty::TraitRef<'tcx> {
p!(write("<{} as {}>", self.self_ty(), self.print_only_trait_path()))
}
TraitRefPrintOnlyTraitPath<'tcx> {
p!(print_def_path(self.0.def_id, self.0.substs));
}
TraitRefPrintOnlyTraitName<'tcx> {
p!(print_def_path(self.0.def_id, &[]));
}
TraitPredPrintModifiersAndPath<'tcx> {
if let ty::BoundConstness::ConstIfConst = self.0.constness {
p!("~const ")
}
if let ty::ImplPolarity::Negative = self.0.polarity {
p!("!")
}
p!(print(self.0.trait_ref.print_only_trait_path()));
}
ty::ParamTy {
p!(write("{}", self.name))
}
ty::ParamConst {
p!(write("{}", self.name))
}
ty::SubtypePredicate<'tcx> {
p!(print(self.a), " <: ", print(self.b))
}
ty::CoercePredicate<'tcx> {
p!(print(self.a), " -> ", print(self.b))
}
ty::TraitPredicate<'tcx> {
p!(print(self.trait_ref.self_ty()), ": ");
if let ty::BoundConstness::ConstIfConst = self.constness && cx.tcx().features().const_trait_impl {
p!("~const ");
}
p!(print(self.trait_ref.print_only_trait_path()))
}
ty::ProjectionPredicate<'tcx> {
p!(print(self.projection_ty), " == ", print(self.term))
}
ty::Term<'tcx> {
match self {
ty::Term::Ty(ty) => p!(print(ty)),
ty::Term::Const(c) => p!(print(c)),
}
}
ty::ProjectionTy<'tcx> {
p!(print_def_path(self.item_def_id, self.substs));
}
ty::ClosureKind {
match *self {
ty::ClosureKind::Fn => p!("Fn"),
ty::ClosureKind::FnMut => p!("FnMut"),
ty::ClosureKind::FnOnce => p!("FnOnce"),
}
}
ty::Predicate<'tcx> {
let binder = self.kind();
p!(print(binder))
}
ty::PredicateKind<'tcx> {
match *self {
ty::PredicateKind::Trait(ref data) => {
p!(print(data))
}
ty::PredicateKind::Subtype(predicate) => p!(print(predicate)),
ty::PredicateKind::Coerce(predicate) => p!(print(predicate)),
ty::PredicateKind::RegionOutlives(predicate) => p!(print(predicate)),
ty::PredicateKind::TypeOutlives(predicate) => p!(print(predicate)),
ty::PredicateKind::Projection(predicate) => p!(print(predicate)),
ty::PredicateKind::WellFormed(arg) => p!(print(arg), " well-formed"),
ty::PredicateKind::ObjectSafe(trait_def_id) => {
p!("the trait `", print_def_path(trait_def_id, &[]), "` is object-safe")
}
ty::PredicateKind::ClosureKind(closure_def_id, _closure_substs, kind) => {
p!("the closure `",
print_value_path(closure_def_id, &[]),
write("` implements the trait `{}`", kind))
}
ty::PredicateKind::ConstEvaluatable(uv) => {
p!("the constant `", print_value_path(uv.def.did, uv.substs), "` can be evaluated")
}
ty::PredicateKind::ConstEquate(c1, c2) => {
p!("the constant `", print(c1), "` equals `", print(c2), "`")
}
ty::PredicateKind::TypeWellFormedFromEnv(ty) => {
p!("the type `", print(ty), "` is found in the environment")
}
}
}
GenericArg<'tcx> {
match self.unpack() {
GenericArgKind::Lifetime(lt) => p!(print(lt)),
GenericArgKind::Type(ty) => p!(print(ty)),
GenericArgKind::Const(ct) => p!(print(ct)),
}
}
}
fn for_each_def(tcx: TyCtxt<'_>, mut collect_fn: impl for<'b> FnMut(&'b Ident, Namespace, DefId)) {
// Iterate all local crate items no matter where they are defined.
let hir = tcx.hir();
for id in hir.items() {
if matches!(tcx.def_kind(id.def_id), DefKind::Use) {
continue;
}
let item = hir.item(id);
if item.ident.name == kw::Empty {
continue;
}
let def_id = item.def_id.to_def_id();
let ns = tcx.def_kind(def_id).ns().unwrap_or(Namespace::TypeNS);
collect_fn(&item.ident, ns, def_id);
}
// Now take care of extern crate items.
let queue = &mut Vec::new();
let mut seen_defs: DefIdSet = Default::default();
for &cnum in tcx.crates(()).iter() {
let def_id = cnum.as_def_id();
// Ignore crates that are not direct dependencies.
match tcx.extern_crate(def_id) {
None => continue,
Some(extern_crate) => {
if !extern_crate.is_direct() {
continue;
}
}
}
queue.push(def_id);
}
// Iterate external crate defs but be mindful about visibility
while let Some(def) = queue.pop() {
for child in tcx.module_children(def).iter() {
if !child.vis.is_public() {
continue;
}
match child.res {
def::Res::Def(DefKind::AssocTy, _) => {}
def::Res::Def(DefKind::TyAlias, _) => {}
def::Res::Def(defkind, def_id) => {
if let Some(ns) = defkind.ns() {
collect_fn(&child.ident, ns, def_id);
}
if matches!(defkind, DefKind::Mod | DefKind::Enum | DefKind::Trait)
&& seen_defs.insert(def_id)
{
queue.push(def_id);
}
}
_ => {}
}
}
}
}
/// The purpose of this function is to collect public symbols names that are unique across all
/// crates in the build. Later, when printing about types we can use those names instead of the
/// full exported path to them.
///
/// So essentially, if a symbol name can only be imported from one place for a type, and as
/// long as it was not glob-imported anywhere in the current crate, we can trim its printed
/// path and print only the name.
///
/// This has wide implications on error messages with types, for example, shortening
/// `std::vec::Vec` to just `Vec`, as long as there is no other `Vec` importable anywhere.
///
/// The implementation uses similar import discovery logic to that of 'use' suggestions.
fn trimmed_def_paths(tcx: TyCtxt<'_>, (): ()) -> FxHashMap<DefId, Symbol> {
let mut map: FxHashMap<DefId, Symbol> = FxHashMap::default();
if let TrimmedDefPaths::GoodPath = tcx.sess.opts.trimmed_def_paths {
// For good paths causing this bug, the `rustc_middle::ty::print::with_no_trimmed_paths`
// wrapper can be used to suppress this query, in exchange for full paths being formatted.
tcx.sess.delay_good_path_bug("trimmed_def_paths constructed");
}
let unique_symbols_rev: &mut FxHashMap<(Namespace, Symbol), Option<DefId>> =
&mut FxHashMap::default();
for symbol_set in tcx.resolutions(()).glob_map.values() {
for symbol in symbol_set {
unique_symbols_rev.insert((Namespace::TypeNS, *symbol), None);
unique_symbols_rev.insert((Namespace::ValueNS, *symbol), None);
unique_symbols_rev.insert((Namespace::MacroNS, *symbol), None);
}
}
for_each_def(tcx, |ident, ns, def_id| {
use std::collections::hash_map::Entry::{Occupied, Vacant};
match unique_symbols_rev.entry((ns, ident.name)) {
Occupied(mut v) => match v.get() {
None => {}
Some(existing) => {
if *existing != def_id {
v.insert(None);
}
}
},
Vacant(v) => {
v.insert(Some(def_id));
}
}
});
for ((_, symbol), opt_def_id) in unique_symbols_rev.drain() {
use std::collections::hash_map::Entry::{Occupied, Vacant};
if let Some(def_id) = opt_def_id {
match map.entry(def_id) {
Occupied(mut v) => {
// A single DefId can be known under multiple names (e.g.,
// with a `pub use ... as ...;`). We need to ensure that the
// name placed in this map is chosen deterministically, so
// if we find multiple names (`symbol`) resolving to the
// same `def_id`, we prefer the lexicographically smallest
// name.
//
// Any stable ordering would be fine here though.
if *v.get() != symbol {
if v.get().as_str() > symbol.as_str() {
v.insert(symbol);
}
}
}
Vacant(v) => {
v.insert(symbol);
}
}
}
}
map
}
pub fn provide(providers: &mut ty::query::Providers) {
*providers = ty::query::Providers { trimmed_def_paths, ..*providers };
}
#[derive(Default)]
pub struct OpaqueFnEntry<'tcx> {
// The trait ref is already stored as a key, so just track if we have it as a real predicate
has_fn_once: bool,
fn_mut_trait_ref: Option<ty::PolyTraitRef<'tcx>>,
fn_trait_ref: Option<ty::PolyTraitRef<'tcx>>,
return_ty: Option<ty::Binder<'tcx, Term<'tcx>>>,
}