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rustc: remove the ability for pretty-printers to override nesting.
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@eddyb
eddyb committed Mar 15, 2019
1 parent c0c485c commit 2a65682
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Showing 2 changed files with 59 additions and 70 deletions.
121 changes: 55 additions & 66 deletions src/librustc/ty/print/pretty.rs
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Expand Up @@ -20,16 +20,16 @@ use std::ops::{Deref, DerefMut};
use super::*;

macro_rules! nest {
($closure:expr) => {
scoped_cx!() = scoped_cx!().nest($closure)?
($e:expr) => {
scoped_cx!() = PrintCx::new(scoped_cx!().tcx, $e?)
}
}
macro_rules! print_inner {
(write ($($data:expr),+)) => {
write!(scoped_cx!(), $($data),+)?
};
($kind:ident ($data:expr)) => {
nest!(|cx| $data.$kind(cx))
nest!($data.$kind(scoped_cx!()))
};
}
macro_rules! p {
Expand Down Expand Up @@ -180,15 +180,6 @@ pub trait PrettyPrinter:
> +
fmt::Write
{
/// Enter a nested print context, for pretty-printing
/// nested components in some larger context.
fn nest<'a, 'gcx, 'tcx, E>(
self: PrintCx<'a, 'gcx, 'tcx, Self>,
f: impl FnOnce(PrintCx<'_, 'gcx, 'tcx, Self>) -> Result<Self, E>,
) -> Result<PrintCx<'a, 'gcx, 'tcx, Self>, E> {
Ok(PrintCx::new(self.tcx, f(self)?))
}

/// Like `print_def_path` but for value paths.
fn print_value_path(
self: PrintCx<'_, '_, 'tcx, Self>,
Expand All @@ -214,11 +205,13 @@ pub trait PrettyPrinter:
) -> Result<Self, Self::Error>
where T: Print<'tcx, Self, Output = Self, Error = Self::Error>
{
define_scoped_cx!(self);

if let Some(first) = elems.next() {
self = self.nest(|cx| first.print(cx))?;
nest!(first.print(self));
for elem in elems {
self.write_str(", ")?;
self = self.nest(|cx| elem.print(cx))?;
nest!(elem.print(self));
}
}
self.ok()
Expand Down Expand Up @@ -355,9 +348,9 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
// 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 starting to print anything.
let mut prefix_success = false;
nest!(|cx| {
let (path, success) = cx.try_print_visible_def_path(visible_parent)?;
let prefix_success;
nest!({
let (path, success) = self.try_print_visible_def_path(visible_parent)?;
prefix_success = success;
Ok(path)
});
Expand Down Expand Up @@ -470,7 +463,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<P::Path, P::Error> {
self = self.nest(print_prefix)?;
self = PrintCx::new(self.tcx, print_prefix(self)?);

self.generic_delimiters(|mut cx| {
define_scoped_cx!(cx);
Expand All @@ -492,7 +485,7 @@ pub struct FmtPrinter<F>(Box<FmtPrinterData<F>>);
pub struct FmtPrinterData<F> {
fmt: F,

empty: bool,
empty_path: bool,
in_value: bool,

used_region_names: FxHashSet<InternedString>,
Expand All @@ -519,7 +512,7 @@ impl<F> FmtPrinter<F> {
pub fn new(fmt: F, ns: Namespace) -> Self {
FmtPrinter(Box::new(FmtPrinterData {
fmt,
empty: true,
empty_path: false,
in_value: ns == Namespace::ValueNS,
used_region_names: Default::default(),
region_index: 0,
Expand All @@ -531,7 +524,6 @@ impl<F> FmtPrinter<F> {

impl<F: fmt::Write> fmt::Write for FmtPrinter<F> {
fn write_str(&mut self, s: &str) -> fmt::Result {
self.empty &= s.is_empty();
self.fmt.write_str(s)
}
}
Expand All @@ -549,16 +541,18 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
def_id: DefId,
substs: Option<SubstsRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
define_scoped_cx!(self);

// FIXME(eddyb) avoid querying `tcx.generics_of` and `tcx.def_key`
// both here and in `default_print_def_path`.
let generics = substs.map(|_| self.tcx.generics_of(def_id));
if generics.as_ref().and_then(|g| g.parent).is_none() {
let mut visible_path_success = false;
self = self.nest(|cx| {
let (path, success) = cx.try_print_visible_def_path(def_id)?;
let visible_path_success;
nest!({
let (path, success) = self.try_print_visible_def_path(def_id)?;
visible_path_success = success;
Ok(path)
})?;
});
if visible_path_success {
return if let (Some(generics), Some(substs)) = (generics, substs) {
let args = self.generic_args_to_print(generics, substs);
Expand Down Expand Up @@ -621,15 +615,18 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
mut self: PrintCx<'_, '_, '_, 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, "{}", keywords::Crate.name())?;
self.empty_path = false;
}
}
} else {
write!(self, "{}", self.tcx.crate_name(cnum))?;
self.empty_path = false;
}
self.ok()
}
Expand All @@ -638,7 +635,9 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
self.pretty_path_qualified(self_ty, trait_ref)
let mut path = self.pretty_path_qualified(self_ty, trait_ref)?;
path.empty_path = false;
Ok(path)
}

fn path_append_impl<'gcx, 'tcx>(
Expand All @@ -649,17 +648,16 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
self.pretty_path_append_impl(|cx| {
let mut path = self.pretty_path_append_impl(|cx| {
let mut path = print_prefix(cx)?;

// HACK(eddyb) this accounts for `generic_delimiters`
// printing `::<` instead of `<` if `in_value` is set.
if !path.empty && !path.in_value {
if !path.empty_path {
write!(path, "::")?;
}

Ok(path)
}, self_ty, trait_ref)
}, self_ty, trait_ref)?;
path.empty_path = false;
Ok(path)
}
fn path_append<'gcx, 'tcx>(
self: PrintCx<'_, 'gcx, 'tcx, Self>,
Expand All @@ -673,10 +671,11 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
// FIXME(eddyb) `text` should never be empty, but it
// currently is for `extern { ... }` "foreign modules".
if !text.is_empty() {
if !path.empty {
if !path.empty_path {
write!(path, "::")?;
}
write!(path, "{}", text)?;
path.empty_path = false;
}

Ok(path)
Expand All @@ -688,7 +687,9 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
) -> Result<Self::Path, Self::Error>,
args: &[Kind<'tcx>],
) -> Result<Self::Path, Self::Error> {
self = self.nest(print_prefix)?;
define_scoped_cx!(self);

nest!(print_prefix(self));

// Don't print `'_` if there's no unerased regions.
let print_regions = args.iter().any(|arg| {
Expand All @@ -705,6 +706,9 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
});

if args.clone().next().is_some() {
if self.in_value {
write!(self, "::")?;
}
self.generic_delimiters(|cx| cx.comma_sep(args))
} else {
self.ok()
Expand All @@ -713,17 +717,6 @@ impl<F: fmt::Write> Printer for FmtPrinter<F> {
}

impl<F: fmt::Write> PrettyPrinter for FmtPrinter<F> {
fn nest<'a, 'gcx, 'tcx, E>(
mut self: PrintCx<'a, 'gcx, 'tcx, Self>,
f: impl FnOnce(PrintCx<'_, 'gcx, 'tcx, Self>) -> Result<Self, E>,
) -> Result<PrintCx<'a, 'gcx, 'tcx, Self>, E> {
let tcx = self.tcx;
let was_empty = std::mem::replace(&mut self.empty, true);
let mut inner = f(self)?;
inner.empty &= was_empty;
Ok(PrintCx::new(tcx, inner))
}

fn print_value_path(
mut self: PrintCx<'_, '_, 'tcx, Self>,
def_id: DefId,
Expand All @@ -749,11 +742,7 @@ impl<F: fmt::Write> PrettyPrinter for FmtPrinter<F> {
mut self: PrintCx<'_, 'gcx, 'tcx, Self>,
f: impl FnOnce(PrintCx<'_, 'gcx, 'tcx, Self>) -> Result<Self, Self::Error>,
) -> Result<Self, Self::Error> {
if !self.empty && self.in_value {
write!(self, "::<")?;
} else {
write!(self, "<")?;
}
write!(self, "<")?;

let was_in_value = std::mem::replace(&mut self.in_value, false);
let mut inner = f(self)?;
Expand Down Expand Up @@ -957,7 +946,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
ty::FnDef(def_id, substs) => {
let sig = self.tcx.fn_sig(def_id).subst(self.tcx, substs);
p!(print(sig), write(" {{"));
nest!(|cx| cx.print_value_path(def_id, Some(substs)));
nest!(self.print_value_path(def_id, Some(substs)));
p!(write("}}"))
}
ty::FnPtr(ref bare_fn) => {
Expand All @@ -980,7 +969,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
}
}
ty::Adt(def, substs) => {
nest!(|cx| cx.print_def_path(def.did, Some(substs)));
nest!(self.print_def_path(def.did, Some(substs)));
}
ty::Dynamic(data, r) => {
let print_r = self.region_should_not_be_omitted(r);
Expand All @@ -993,7 +982,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
}
}
ty::Foreign(def_id) => {
nest!(|cx| cx.print_def_path(def_id, None));
nest!(self.print_def_path(def_id, None));
}
ty::Projection(ref data) => p!(print(data)),
ty::UnnormalizedProjection(ref data) => {
Expand Down Expand Up @@ -1094,7 +1083,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
p!(write(" "), print(witness), write("]"))
},
ty::GeneratorWitness(types) => {
nest!(|cx| cx.in_binder(&types))
nest!(self.in_binder(&types))
}
ty::Closure(did, substs) => {
let upvar_tys = substs.upvar_tys(did, self.tcx);
Expand Down Expand Up @@ -1179,7 +1168,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
let mut first = true;

if let Some(principal) = predicates.principal() {
nest!(|cx| cx.print_def_path(principal.def_id, None));
nest!(self.print_def_path(principal.def_id, None));

let mut resugared = false;

Expand All @@ -1189,7 +1178,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
if let ty::Tuple(ref args) = principal.substs.type_at(0).sty {
let mut projections = predicates.projection_bounds();
if let (Some(proj), None) = (projections.next(), projections.next()) {
nest!(|cx| cx.pretty_fn_sig(args, false, proj.ty));
nest!(self.pretty_fn_sig(args, false, proj.ty));
resugared = true;
}
}
Expand Down Expand Up @@ -1228,8 +1217,8 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
let args = arg0.into_iter().chain(args);
let projections = projection0.into_iter().chain(projections);

nest!(|cx| cx.generic_delimiters(|mut cx| {
cx = cx.nest(|cx| cx.comma_sep(args))?;
nest!(self.generic_delimiters(|mut cx| {
cx = PrintCx::new(cx.tcx, cx.comma_sep(args)?);
if arg0.is_some() && projection0.is_some() {
write!(cx, ", ")?;
}
Expand Down Expand Up @@ -1262,7 +1251,7 @@ impl<'gcx, 'tcx, P: PrettyPrinter> PrintCx<'_, 'gcx, 'tcx, P> {
}
first = false;

nest!(|cx| cx.print_def_path(def_id, None));
nest!(self.print_def_path(def_id, None));
}

self.ok()
Expand Down Expand Up @@ -1531,7 +1520,7 @@ define_print_and_forward_display! {
ty::ExistentialPredicate::Trait(x) => p!(print(x)),
ty::ExistentialPredicate::Projection(x) => p!(print(x)),
ty::ExistentialPredicate::AutoTrait(def_id) => {
nest!(|cx| cx.print_def_path(def_id, None))
nest!(cx.print_def_path(def_id, None))
}
}
}
Expand All @@ -1546,7 +1535,7 @@ define_print_and_forward_display! {
}

p!(write("fn"));
nest!(|cx| cx.pretty_fn_sig(self.inputs(), self.c_variadic, self.output()));
nest!(cx.pretty_fn_sig(self.inputs(), self.c_variadic, self.output()));
}

ty::InferTy {
Expand All @@ -1565,7 +1554,7 @@ define_print_and_forward_display! {
}

ty::TraitRef<'tcx> {
nest!(|cx| cx.print_def_path(self.def_id, Some(self.substs)));
nest!(cx.print_def_path(self.def_id, Some(self.substs)));
}

ConstValue<'tcx> {
Expand Down Expand Up @@ -1609,7 +1598,7 @@ define_print_and_forward_display! {
}

ty::ProjectionTy<'tcx> {
nest!(|cx| cx.print_def_path(self.item_def_id, Some(self.substs)));
nest!(cx.print_def_path(self.item_def_id, Some(self.substs)));
}

ty::ClosureKind {
Expand All @@ -1630,17 +1619,17 @@ define_print_and_forward_display! {
ty::Predicate::WellFormed(ty) => p!(print(ty), write(" well-formed")),
ty::Predicate::ObjectSafe(trait_def_id) => {
p!(write("the trait `"));
nest!(|cx| cx.print_def_path(trait_def_id, None));
nest!(cx.print_def_path(trait_def_id, None));
p!(write("` is object-safe"))
}
ty::Predicate::ClosureKind(closure_def_id, _closure_substs, kind) => {
p!(write("the closure `"));
nest!(|cx| cx.print_value_path(closure_def_id, None));
nest!(cx.print_value_path(closure_def_id, None));
p!(write("` implements the trait `{}`", kind))
}
ty::Predicate::ConstEvaluatable(def_id, substs) => {
p!(write("the constant `"));
nest!(|cx| cx.print_value_path(def_id, Some(substs)));
nest!(cx.print_value_path(def_id, Some(substs)));
p!(write("` can be evaluated"))
}
}
Expand Down

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