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Auto merge of #116815 - Nilstrieb:more-funny-pretty-printers, r=compi…
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…ler-errors

Remove lots of generics from `ty::print`

All of these generics mostly resolve to the same thing, which means we can remove them, greatly simplifying the types involved in pretty printing and unlocking another simplification (that is not performed in this PR): Using `&mut self` instead of passing `self` through the return type.

cc `@eddyb` you probably know why it's like this, just checking in and making sure I didn't do anything bad

r? oli-obk
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@bors
bors committed Oct 18, 2023
2 parents 6d7160c + 6fc6a6d commit e8b8c78
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Showing 9 changed files with 214 additions and 310 deletions.
42 changes: 17 additions & 25 deletions compiler/rustc_const_eval/src/util/type_name.rs
View file
Expand Up @@ -3,7 +3,7 @@ use rustc_hir::def_id::CrateNum;
use rustc_hir::definitions::DisambiguatedDefPathData;
use rustc_middle::ty::{
self,
print::{PrettyPrinter, Print, Printer},
print::{PrettyPrinter, Print, PrintError, Printer},
GenericArg, GenericArgKind, Ty, TyCtxt,
};
use std::fmt::Write;
Expand All @@ -14,23 +14,15 @@ struct AbsolutePathPrinter<'tcx> {
}

impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
type Error = std::fmt::Error;

type Path = Self;
type Region = Self;
type Type = Self;
type DynExistential = Self;
type Const = Self;

fn tcx(&self) -> TyCtxt<'tcx> {
self.tcx
}

fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> {
fn print_region(self, _region: ty::Region<'_>) -> Result<Self, PrintError> {
Ok(self)
}

fn print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
fn print_type(mut self, ty: Ty<'tcx>) -> Result<Self, PrintError> {
match *ty.kind() {
// Types without identity.
ty::Bool
Expand Down Expand Up @@ -68,18 +60,18 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
}
}

fn print_const(self, ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
fn print_const(self, ct: ty::Const<'tcx>) -> Result<Self, PrintError> {
self.pretty_print_const(ct, false)
}

fn print_dyn_existential(
self,
predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
) -> Result<Self::DynExistential, Self::Error> {
) -> Result<Self, PrintError> {
self.pretty_print_dyn_existential(predicates)
}

fn path_crate(mut self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
fn path_crate(mut self, cnum: CrateNum) -> Result<Self, PrintError> {
self.path.push_str(self.tcx.crate_name(cnum).as_str());
Ok(self)
}
Expand All @@ -88,17 +80,17 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
self,
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
) -> Result<Self, PrintError> {
self.pretty_path_qualified(self_ty, trait_ref)
}

fn path_append_impl(
self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
print_prefix: impl FnOnce(Self) -> Result<Self, PrintError>,
_disambiguated_data: &DisambiguatedDefPathData,
self_ty: Ty<'tcx>,
trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
) -> Result<Self, PrintError> {
self.pretty_path_append_impl(
|mut cx| {
cx = print_prefix(cx)?;
Expand All @@ -114,9 +106,9 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {

fn path_append(
mut self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
print_prefix: impl FnOnce(Self) -> Result<Self, PrintError>,
disambiguated_data: &DisambiguatedDefPathData,
) -> Result<Self::Path, Self::Error> {
) -> Result<Self, PrintError> {
self = print_prefix(self)?;

write!(self.path, "::{}", disambiguated_data.data).unwrap();
Expand All @@ -126,9 +118,9 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {

fn path_generic_args(
mut self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
print_prefix: impl FnOnce(Self) -> Result<Self, PrintError>,
args: &[GenericArg<'tcx>],
) -> Result<Self::Path, Self::Error> {
) -> Result<Self, PrintError> {
self = print_prefix(self)?;
let args =
args.iter().cloned().filter(|arg| !matches!(arg.unpack(), GenericArgKind::Lifetime(_)));
Expand All @@ -144,9 +136,9 @@ impl<'tcx> PrettyPrinter<'tcx> for AbsolutePathPrinter<'tcx> {
fn should_print_region(&self, _region: ty::Region<'_>) -> bool {
false
}
fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, Self::Error>
fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, PrintError>
where
T: Print<'tcx, Self, Output = Self, Error = Self::Error>,
T: Print<'tcx, Self>,
{
if let Some(first) = elems.next() {
self = first.print(self)?;
Expand All @@ -160,8 +152,8 @@ impl<'tcx> PrettyPrinter<'tcx> for AbsolutePathPrinter<'tcx> {

fn generic_delimiters(
mut self,
f: impl FnOnce(Self) -> Result<Self, Self::Error>,
) -> Result<Self, Self::Error> {
f: impl FnOnce(Self) -> Result<Self, PrintError>,
) -> Result<Self, PrintError> {
write!(self, "<")?;

self = f(self)?;
Expand Down
69 changes: 32 additions & 37 deletions compiler/rustc_infer/src/infer/error_reporting/mod.rs
View file
Expand Up @@ -67,7 +67,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::Visitor;
use rustc_hir::lang_items::LangItem;
use rustc_middle::dep_graph::DepContext;
use rustc_middle::ty::print::with_forced_trimmed_paths;
use rustc_middle::ty::print::{with_forced_trimmed_paths, PrintError};
use rustc_middle::ty::relate::{self, RelateResult, TypeRelation};
use rustc_middle::ty::{
self, error::TypeError, IsSuggestable, List, Region, Ty, TyCtxt, TypeFoldable,
Expand Down Expand Up @@ -580,76 +580,68 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {

struct AbsolutePathPrinter<'tcx> {
tcx: TyCtxt<'tcx>,
segments: Vec<String>,
}

struct NonTrivialPath;

impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
type Error = NonTrivialPath;

type Path = Vec<String>;
type Region = !;
type Type = !;
type DynExistential = !;
type Const = !;

fn tcx<'a>(&'a self) -> TyCtxt<'tcx> {
self.tcx
}

fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> {
Err(NonTrivialPath)
fn print_region(self, _region: ty::Region<'_>) -> Result<Self, PrintError> {
Err(fmt::Error)
}

fn print_type(self, _ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
Err(NonTrivialPath)
fn print_type(self, _ty: Ty<'tcx>) -> Result<Self, PrintError> {
Err(fmt::Error)
}

fn print_dyn_existential(
self,
_predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
) -> Result<Self::DynExistential, Self::Error> {
Err(NonTrivialPath)
) -> Result<Self, PrintError> {
Err(fmt::Error)
}

fn print_const(self, _ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
Err(NonTrivialPath)
fn print_const(self, _ct: ty::Const<'tcx>) -> Result<Self, PrintError> {
Err(fmt::Error)
}

fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
Ok(vec![self.tcx.crate_name(cnum).to_string()])
fn path_crate(mut self, cnum: CrateNum) -> Result<Self, PrintError> {
self.segments = vec![self.tcx.crate_name(cnum).to_string()];
Ok(self)
}
fn path_qualified(
self,
_self_ty: Ty<'tcx>,
_trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
Err(NonTrivialPath)
) -> Result<Self, PrintError> {
Err(fmt::Error)
}

fn path_append_impl(
self,
_print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
_print_prefix: impl FnOnce(Self) -> Result<Self, PrintError>,
_disambiguated_data: &DisambiguatedDefPathData,
_self_ty: Ty<'tcx>,
_trait_ref: Option<ty::TraitRef<'tcx>>,
) -> Result<Self::Path, Self::Error> {
Err(NonTrivialPath)
) -> Result<Self, PrintError> {
Err(fmt::Error)
}
fn path_append(
self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
mut self,
print_prefix: impl FnOnce(Self) -> Result<Self, PrintError>,
disambiguated_data: &DisambiguatedDefPathData,
) -> Result<Self::Path, Self::Error> {
let mut path = print_prefix(self)?;
path.push(disambiguated_data.to_string());
Ok(path)
) -> Result<Self, PrintError> {
self = print_prefix(self)?;
self.segments.push(disambiguated_data.to_string());
Ok(self)
}
fn path_generic_args(
self,
print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
print_prefix: impl FnOnce(Self) -> Result<Self, PrintError>,
_args: &[GenericArg<'tcx>],
) -> Result<Self::Path, Self::Error> {
) -> Result<Self, PrintError> {
print_prefix(self)
}
}
Expand All @@ -659,12 +651,15 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
// are from a local module we could have false positives, e.g.
// let _ = [{struct Foo; Foo}, {struct Foo; Foo}];
if did1.krate != did2.krate {
let abs_path =
|def_id| AbsolutePathPrinter { tcx: self.tcx }.print_def_path(def_id, &[]);
let abs_path = |def_id| {
AbsolutePathPrinter { tcx: self.tcx, segments: vec![] }
.print_def_path(def_id, &[])
.map(|p| p.segments)
};

// We compare strings because DefPath can be different
// for imported and non-imported crates
let same_path = || -> Result<_, NonTrivialPath> {
let same_path = || -> Result<_, PrintError> {
Ok(self.tcx.def_path_str(did1) == self.tcx.def_path_str(did2)
|| abs_path(did1)? == abs_path(did2)?)
};
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs
View file
Expand Up @@ -28,7 +28,7 @@ pub struct Highlighted<'tcx, T> {

impl<'tcx, T> IntoDiagnosticArg for Highlighted<'tcx, T>
where
T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>, Error = fmt::Error, Output = FmtPrinter<'a, 'tcx>>,
T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>>,
{
fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
rustc_errors::DiagnosticArgValue::Str(self.to_string().into())
Expand All @@ -43,7 +43,7 @@ impl<'tcx, T> Highlighted<'tcx, T> {

impl<'tcx, T> fmt::Display for Highlighted<'tcx, T>
where
T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>, Error = fmt::Error, Output = FmtPrinter<'a, 'tcx>>,
T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>>,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut printer = ty::print::FmtPrinter::new(self.tcx, Namespace::TypeNS);
Expand Down

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