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Auto merge of #127500 - compiler-errors:consolidate-region-errors, r=lcnr

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Consolidate region error reporting in `rustc_infer`

More work on https://github.com/rust-lang/rust/issues/127492. Separate but important step, since I'm gonna likely pull everything else here into another module.

I don't think I'm confident whether `nice_region_error` should be a submodule of the new `rustc_infer::infer::error_reporting::region` module, so I left it alone for now.

r? lcnr
This commit is contained in:
bors 2024-07-09 13:43:15 +00:00
commit f25e92bd42
4 changed files with 1273 additions and 1270 deletions
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8
compiler/rustc_borrowck/src/diagnostics/region_errors.rs
View File

@ -10,14 +10,12 @@ use rustc_hir::GenericBound::Trait;
use rustc_hir::QPath::Resolved;
use rustc_hir::WherePredicate::BoundPredicate;
use rustc_hir::{PolyTraitRef, TyKind, WhereBoundPredicate};
use rustc_infer::infer::{
error_reporting::nice_region_error::{
use rustc_infer::infer::error_reporting::nice_region_error::{
self, find_anon_type, find_param_with_region, suggest_adding_lifetime_params,
HirTraitObjectVisitor, NiceRegionError, TraitObjectVisitor,
},
error_reporting::unexpected_hidden_region_diagnostic,
NllRegionVariableOrigin, RelateParamBound,
};
use rustc_infer::infer::error_reporting::region::unexpected_hidden_region_diagnostic;
use rustc_infer::infer::{NllRegionVariableOrigin, RelateParamBound};
use rustc_middle::bug;
use rustc_middle::hir::place::PlaceBase;
use rustc_middle::mir::{ConstraintCategory, ReturnConstraint};

851
compiler/rustc_infer/src/infer/error_reporting/mod.rs
View File

@ -45,13 +45,10 @@
//! ported to this system, and which relies on string concatenation at the
//! time of error detection.
use super::lexical_region_resolve::RegionResolutionError;
use super::region_constraints::GenericKind;
use super::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TypeTrace, ValuePairs};
use super::{InferCtxt, TypeTrace, ValuePairs};
use crate::errors::{self, ObligationCauseFailureCode, TypeErrorAdditionalDiags};
use crate::errors::{ObligationCauseFailureCode, TypeErrorAdditionalDiags};
use crate::infer;
use crate::infer::error_reporting::nice_region_error::find_anon_type::find_anon_type;
use crate::infer::ExpectedFound;
use crate::traits::{
IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode,
@ -61,38 +58,36 @@ use crate::traits::{
use crate::infer::relate::{self, RelateResult, TypeRelation};
use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
use rustc_errors::{
codes::*, pluralize, struct_span_code_err, Applicability, Diag, DiagCtxtHandle,
DiagStyledString, ErrorGuaranteed, IntoDiagArg, StringPart,
pluralize, Applicability, Diag, DiagCtxtHandle, DiagStyledString, IntoDiagArg, StringPart,
};
use rustc_hir::def::DefKind;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::def_id::DefId;
use rustc_hir::intravisit::Visitor;
use rustc_hir::lang_items::LangItem;
use rustc_hir::{self as hir, ParamName};
use rustc_hir::{self as hir};
use rustc_macros::extension;
use rustc_middle::bug;
use rustc_middle::dep_graph::DepContext;
use rustc_middle::ty::error::TypeErrorToStringExt;
use rustc_middle::ty::print::{with_forced_trimmed_paths, PrintError, PrintTraitRefExt as _};
use rustc_middle::ty::Upcast;
use rustc_middle::ty::{
self, error::TypeError, IsSuggestable, List, Region, Ty, TyCtxt, TypeFoldable,
TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
self, error::TypeError, List, Region, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable,
TypeVisitable, TypeVisitableExt,
};
use rustc_span::{sym, symbol::kw, BytePos, DesugaringKind, Pos, Span};
use rustc_span::{sym, BytePos, DesugaringKind, Pos, Span};
use rustc_target::spec::abi;
use std::borrow::Cow;
use std::ops::{ControlFlow, Deref};
use std::path::PathBuf;
use std::{cmp, fmt, iter};
mod note;
mod note_and_explain;
mod suggest;
pub(crate) mod need_type_info;
pub mod sub_relations;
pub use need_type_info::TypeAnnotationNeeded;
pub mod region;
pub mod nice_region_error;
@ -159,245 +154,6 @@ impl<'tcx> Deref for TypeErrCtxt<'_, 'tcx> {
}
}
pub(super) fn note_and_explain_region<'tcx>(
tcx: TyCtxt<'tcx>,
err: &mut Diag<'_>,
generic_param_scope: LocalDefId,
prefix: &str,
region: ty::Region<'tcx>,
suffix: &str,
alt_span: Option<Span>,
) {
let (description, span) = match *region {
ty::ReEarlyParam(_) | ty::ReLateParam(_) | ty::RePlaceholder(_) | ty::ReStatic => {
msg_span_from_named_region(tcx, generic_param_scope, region, alt_span)
}
ty::ReError(_) => return,
// FIXME(#125431): `ReVar` shouldn't reach here.
ty::ReVar(_) => (format!("lifetime `{region}`"), alt_span),
ty::ReBound(..) | ty::ReErased => {
bug!("unexpected region for note_and_explain_region: {:?}", region);
}
};
emit_msg_span(err, prefix, description, span, suffix);
}
fn explain_free_region<'tcx>(
tcx: TyCtxt<'tcx>,
err: &mut Diag<'_>,
generic_param_scope: LocalDefId,
prefix: &str,
region: ty::Region<'tcx>,
suffix: &str,
) {
let (description, span) = msg_span_from_named_region(tcx, generic_param_scope, region, None);
label_msg_span(err, prefix, description, span, suffix);
}
fn msg_span_from_named_region<'tcx>(
tcx: TyCtxt<'tcx>,
generic_param_scope: LocalDefId,
region: ty::Region<'tcx>,
alt_span: Option<Span>,
) -> (String, Option<Span>) {
match *region {
ty::ReEarlyParam(br) => {
let scope = tcx
.parent(tcx.generics_of(generic_param_scope).region_param(br, tcx).def_id)
.expect_local();
let span = if let Some(param) =
tcx.hir().get_generics(scope).and_then(|generics| generics.get_named(br.name))
{
param.span
} else {
tcx.def_span(scope)
};
let text = if br.has_name() {
format!("the lifetime `{}` as defined here", br.name)
} else {
"the anonymous lifetime as defined here".to_string()
};
(text, Some(span))
}
ty::ReLateParam(ref fr) => {
if !fr.bound_region.is_named()
&& let Some((ty, _)) =
find_anon_type(tcx, generic_param_scope, region, &fr.bound_region)
{
("the anonymous lifetime defined here".to_string(), Some(ty.span))
} else {
match fr.bound_region {
ty::BoundRegionKind::BrNamed(_, name) => {
let span = if let Some(param) = tcx
.hir()
.get_generics(generic_param_scope)
.and_then(|generics| generics.get_named(name))
{
param.span
} else {
tcx.def_span(generic_param_scope)
};
let text = if name == kw::UnderscoreLifetime {
"the anonymous lifetime as defined here".to_string()
} else {
format!("the lifetime `{name}` as defined here")
};
(text, Some(span))
}
ty::BrAnon => (
"the anonymous lifetime as defined here".to_string(),
Some(tcx.def_span(generic_param_scope)),
),
_ => (
format!("the lifetime `{region}` as defined here"),
Some(tcx.def_span(generic_param_scope)),
),
}
}
}
ty::ReStatic => ("the static lifetime".to_owned(), alt_span),
ty::RePlaceholder(ty::PlaceholderRegion {
bound: ty::BoundRegion { kind: ty::BoundRegionKind::BrNamed(def_id, name), .. },
..
}) => (format!("the lifetime `{name}` as defined here"), Some(tcx.def_span(def_id))),
ty::RePlaceholder(ty::PlaceholderRegion {
bound: ty::BoundRegion { kind: ty::BoundRegionKind::BrAnon, .. },
..
}) => ("an anonymous lifetime".to_owned(), None),
_ => bug!("{:?}", region),
}
}
fn emit_msg_span(
err: &mut Diag<'_>,
prefix: &str,
description: String,
span: Option<Span>,
suffix: &str,
) {
let message = format!("{prefix}{description}{suffix}");
if let Some(span) = span {
err.span_note(span, message);
} else {
err.note(message);
}
}
fn label_msg_span(
err: &mut Diag<'_>,
prefix: &str,
description: String,
span: Option<Span>,
suffix: &str,
) {
let message = format!("{prefix}{description}{suffix}");
if let Some(span) = span {
err.span_label(span, message);
} else {
err.note(message);
}
}
#[instrument(level = "trace", skip(infcx))]
pub fn unexpected_hidden_region_diagnostic<'a, 'tcx>(
infcx: &'a InferCtxt<'tcx>,
generic_param_scope: LocalDefId,
span: Span,
hidden_ty: Ty<'tcx>,
hidden_region: ty::Region<'tcx>,
opaque_ty_key: ty::OpaqueTypeKey<'tcx>,
) -> Diag<'a> {
let tcx = infcx.tcx;
let mut err = infcx.dcx().create_err(errors::OpaqueCapturesLifetime {
span,
opaque_ty: Ty::new_opaque(tcx, opaque_ty_key.def_id.to_def_id(), opaque_ty_key.args),
opaque_ty_span: tcx.def_span(opaque_ty_key.def_id),
});
// Explain the region we are capturing.
match *hidden_region {
ty::ReEarlyParam(_) | ty::ReLateParam(_) | ty::ReStatic => {
// Assuming regionck succeeded (*), we ought to always be
// capturing *some* region from the fn header, and hence it
// ought to be free. So under normal circumstances, we will go
// down this path which gives a decent human readable
// explanation.
//
// (*) if not, the `tainted_by_errors` field would be set to
// `Some(ErrorGuaranteed)` in any case, so we wouldn't be here at all.
explain_free_region(
tcx,
&mut err,
generic_param_scope,
&format!("hidden type `{hidden_ty}` captures "),
hidden_region,
"",
);
if let Some(reg_info) = tcx.is_suitable_region(generic_param_scope, hidden_region) {
let fn_returns = tcx.return_type_impl_or_dyn_traits(reg_info.def_id);
nice_region_error::suggest_new_region_bound(
tcx,
&mut err,
fn_returns,
hidden_region.to_string(),
None,
format!("captures `{hidden_region}`"),
None,
Some(reg_info.def_id),
)
}
}
ty::RePlaceholder(_) => {
explain_free_region(
tcx,
&mut err,
generic_param_scope,
&format!("hidden type `{}` captures ", hidden_ty),
hidden_region,
"",
);
}
ty::ReError(_) => {
err.downgrade_to_delayed_bug();
}
_ => {
// Ugh. This is a painful case: the hidden region is not one
// that we can easily summarize or explain. This can happen
// in a case like
// `tests/ui/multiple-lifetimes/ordinary-bounds-unsuited.rs`:
//
// ```
// fn upper_bounds<'a, 'b>(a: Ordinary<'a>, b: Ordinary<'b>) -> impl Trait<'a, 'b> {
// if condition() { a } else { b }
// }
// ```
//
// Here the captured lifetime is the intersection of `'a` and
// `'b`, which we can't quite express.
// We can at least report a really cryptic error for now.
note_and_explain_region(
tcx,
&mut err,
generic_param_scope,
&format!("hidden type `{hidden_ty}` captures "),
hidden_region,
"",
None,
);
}
}
err
}
impl<'tcx> InferCtxt<'tcx> {
pub fn get_impl_future_output_ty(&self, ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
let (def_id, args) = match *ty.kind() {
@ -438,193 +194,6 @@ impl<'tcx> InferCtxt<'tcx> {
}
impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
pub fn report_region_errors(
&self,
generic_param_scope: LocalDefId,
errors: &[RegionResolutionError<'tcx>],
) -> ErrorGuaranteed {
assert!(!errors.is_empty());
if let Some(guaranteed) = self.infcx.tainted_by_errors() {
return guaranteed;
}
debug!("report_region_errors(): {} errors to start", errors.len());
// try to pre-process the errors, which will group some of them
// together into a `ProcessedErrors` group:
let errors = self.process_errors(errors);
debug!("report_region_errors: {} errors after preprocessing", errors.len());
let mut guar = None;
for error in errors {
debug!("report_region_errors: error = {:?}", error);
let e = if let Some(guar) =
self.try_report_nice_region_error(generic_param_scope, &error)
{
guar
} else {
match error.clone() {
// These errors could indicate all manner of different
// problems with many different solutions. Rather
// than generate a "one size fits all" error, what we
// attempt to do is go through a number of specific
// scenarios and try to find the best way to present
// the error. If all of these fails, we fall back to a rather
// general bit of code that displays the error information
RegionResolutionError::ConcreteFailure(origin, sub, sup) => {
if sub.is_placeholder() || sup.is_placeholder() {
self.report_placeholder_failure(generic_param_scope, origin, sub, sup)
.emit()
} else {
self.report_concrete_failure(generic_param_scope, origin, sub, sup)
.emit()
}
}
RegionResolutionError::GenericBoundFailure(origin, param_ty, sub) => self
.report_generic_bound_failure(
generic_param_scope,
origin.span(),
Some(origin),
param_ty,
sub,
),
RegionResolutionError::SubSupConflict(
_,
var_origin,
sub_origin,
sub_r,
sup_origin,
sup_r,
_,
) => {
if sub_r.is_placeholder() {
self.report_placeholder_failure(
generic_param_scope,
sub_origin,
sub_r,
sup_r,
)
.emit()
} else if sup_r.is_placeholder() {
self.report_placeholder_failure(
generic_param_scope,
sup_origin,
sub_r,
sup_r,
)
.emit()
} else {
self.report_sub_sup_conflict(
generic_param_scope,
var_origin,
sub_origin,
sub_r,
sup_origin,
sup_r,
)
}
}
RegionResolutionError::UpperBoundUniverseConflict(
_,
_,
_,
sup_origin,
sup_r,
) => {
assert!(sup_r.is_placeholder());
// Make a dummy value for the "sub region" --
// this is the initial value of the
// placeholder. In practice, we expect more
// tailored errors that don't really use this
// value.
let sub_r = self.tcx.lifetimes.re_erased;
self.report_placeholder_failure(
generic_param_scope,
sup_origin,
sub_r,
sup_r,
)
.emit()
}
RegionResolutionError::CannotNormalize(clause, origin) => {
let clause: ty::Clause<'tcx> =
clause.map_bound(ty::ClauseKind::TypeOutlives).upcast(self.tcx);
self.tcx
.dcx()
.struct_span_err(origin.span(), format!("cannot normalize `{clause}`"))
.emit()
}
}
};
guar = Some(e)
}
guar.unwrap()
}
// This method goes through all the errors and try to group certain types
// of error together, for the purpose of suggesting explicit lifetime
// parameters to the user. This is done so that we can have a more
// complete view of what lifetimes should be the same.
// If the return value is an empty vector, it means that processing
// failed (so the return value of this method should not be used).
//
// The method also attempts to weed out messages that seem like
// duplicates that will be unhelpful to the end-user. But
// obviously it never weeds out ALL errors.
fn process_errors(
&self,
errors: &[RegionResolutionError<'tcx>],
) -> Vec<RegionResolutionError<'tcx>> {
debug!("process_errors()");
// We want to avoid reporting generic-bound failures if we can
// avoid it: these have a very high rate of being unhelpful in
// practice. This is because they are basically secondary
// checks that test the state of the region graph after the
// rest of inference is done, and the other kinds of errors
// indicate that the region constraint graph is internally
// inconsistent, so these test results are likely to be
// meaningless.
//
// Therefore, we filter them out of the list unless they are
// the only thing in the list.
let is_bound_failure = |e: &RegionResolutionError<'tcx>| match *e {
RegionResolutionError::GenericBoundFailure(..) => true,
RegionResolutionError::ConcreteFailure(..)
| RegionResolutionError::SubSupConflict(..)
| RegionResolutionError::UpperBoundUniverseConflict(..)
| RegionResolutionError::CannotNormalize(..) => false,
};
let mut errors = if errors.iter().all(|e| is_bound_failure(e)) {
errors.to_owned()
} else {
errors.iter().filter(|&e| !is_bound_failure(e)).cloned().collect()
};
// sort the errors by span, for better error message stability.
errors.sort_by_key(|u| match *u {
RegionResolutionError::ConcreteFailure(ref sro, _, _) => sro.span(),
RegionResolutionError::GenericBoundFailure(ref sro, _, _) => sro.span(),
RegionResolutionError::SubSupConflict(_, ref rvo, _, _, _, _, _) => rvo.span(),
RegionResolutionError::UpperBoundUniverseConflict(_, ref rvo, _, _, _) => rvo.span(),
RegionResolutionError::CannotNormalize(_, ref sro) => sro.span(),
});
errors
}
/// Adds a note if the types come from similarly named crates
fn check_and_note_conflicting_crates(&self, err: &mut Diag<'_>, terr: TypeError<'tcx>) {
use hir::def_id::CrateNum;
@ -2341,359 +1910,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
))
}
pub fn report_generic_bound_failure(
&self,
generic_param_scope: LocalDefId,
span: Span,
origin: Option<SubregionOrigin<'tcx>>,
bound_kind: GenericKind<'tcx>,
sub: Region<'tcx>,
) -> ErrorGuaranteed {
self.construct_generic_bound_failure(generic_param_scope, span, origin, bound_kind, sub)
.emit()
}
pub fn construct_generic_bound_failure(
&self,
generic_param_scope: LocalDefId,
span: Span,
origin: Option<SubregionOrigin<'tcx>>,
bound_kind: GenericKind<'tcx>,
sub: Region<'tcx>,
) -> Diag<'a> {
if let Some(SubregionOrigin::CompareImplItemObligation {
span,
impl_item_def_id,
trait_item_def_id,
}) = origin
{
return self.infcx.report_extra_impl_obligation(
span,
impl_item_def_id,
trait_item_def_id,
&format!("`{bound_kind}: {sub}`"),
);
}
let labeled_user_string = match bound_kind {
GenericKind::Param(ref p) => format!("the parameter type `{p}`"),
GenericKind::Placeholder(ref p) => format!("the placeholder type `{p:?}`"),
GenericKind::Alias(ref p) => match p.kind(self.tcx) {
ty::Projection | ty::Inherent => {
format!("the associated type `{p}`")
}
ty::Weak => format!("the type alias `{p}`"),
ty::Opaque => format!("the opaque type `{p}`"),
},
};
let mut err = self
.tcx
.dcx()
.struct_span_err(span, format!("{labeled_user_string} may not live long enough"));
err.code(match sub.kind() {
ty::ReEarlyParam(_) | ty::ReLateParam(_) if sub.has_name() => E0309,
ty::ReStatic => E0310,
_ => E0311,
});
'_explain: {
let (description, span) = match sub.kind() {
ty::ReEarlyParam(_) | ty::ReLateParam(_) | ty::ReStatic => {
msg_span_from_named_region(self.tcx, generic_param_scope, sub, Some(span))
}
_ => (format!("lifetime `{sub}`"), Some(span)),
};
let prefix = format!("{labeled_user_string} must be valid for ");
label_msg_span(&mut err, &prefix, description, span, "...");
if let Some(origin) = origin {
self.note_region_origin(&mut err, &origin);
}
}
'suggestion: {
let msg = "consider adding an explicit lifetime bound";
if (bound_kind, sub).has_infer_regions()
|| (bound_kind, sub).has_placeholders()
|| !bound_kind.is_suggestable(self.tcx, false)
{
let lt_name = sub.get_name_or_anon().to_string();
err.help(format!("{msg} `{bound_kind}: {lt_name}`..."));
break 'suggestion;
}
let mut generic_param_scope = generic_param_scope;
while self.tcx.def_kind(generic_param_scope) == DefKind::OpaqueTy {
generic_param_scope = self.tcx.local_parent(generic_param_scope);
}
// type_param_sugg_span is (span, has_bounds, needs_parentheses)
let (type_scope, type_param_sugg_span) = match bound_kind {
GenericKind::Param(param) => {
let generics = self.tcx.generics_of(generic_param_scope);
let type_param = generics.type_param(param, self.tcx);
let def_id = type_param.def_id.expect_local();
let scope = self.tcx.local_def_id_to_hir_id(def_id).owner.def_id;
// Get the `hir::Param` to verify whether it already has any bounds.
// We do this to avoid suggesting code that ends up as `T: 'a'b`,
// instead we suggest `T: 'a + 'b` in that case.
let hir_generics = self.tcx.hir().get_generics(scope).unwrap();
let sugg_span = match hir_generics.bounds_span_for_suggestions(def_id) {
Some((span, open_paren_sp)) => Some((span, true, open_paren_sp)),
// If `param` corresponds to `Self`, no usable suggestion span.
None if generics.has_self && param.index == 0 => None,
None => {
let span = if let Some(param) =
hir_generics.params.iter().find(|param| param.def_id == def_id)
&& let ParamName::Plain(ident) = param.name
{
ident.span.shrink_to_hi()
} else {
let span = self.tcx.def_span(def_id);
span.shrink_to_hi()
};
Some((span, false, None))
}
};
(scope, sugg_span)
}
_ => (generic_param_scope, None),
};
let suggestion_scope = {
let lifetime_scope = match sub.kind() {
ty::ReStatic => hir::def_id::CRATE_DEF_ID,
_ => match self.tcx.is_suitable_region(generic_param_scope, sub) {
Some(info) => info.def_id,
None => generic_param_scope,
},
};
match self.tcx.is_descendant_of(type_scope.into(), lifetime_scope.into()) {
true => type_scope,
false => lifetime_scope,
}
};
let mut suggs = vec![];
let lt_name = self.suggest_name_region(generic_param_scope, sub, &mut suggs);
if let Some((sp, has_lifetimes, open_paren_sp)) = type_param_sugg_span
&& suggestion_scope == type_scope
{
let suggestion =
if has_lifetimes { format!(" + {lt_name}") } else { format!(": {lt_name}") };
if let Some(open_paren_sp) = open_paren_sp {
suggs.push((open_paren_sp, "(".to_string()));
suggs.push((sp, format!("){suggestion}")));
} else {
suggs.push((sp, suggestion))
}
} else if let GenericKind::Alias(ref p) = bound_kind
&& let ty::Projection = p.kind(self.tcx)
&& let DefKind::AssocTy = self.tcx.def_kind(p.def_id)
&& let Some(ty::ImplTraitInTraitData::Trait { .. }) =
self.tcx.opt_rpitit_info(p.def_id)
{
// The lifetime found in the `impl` is longer than the one on the RPITIT.
// Do not suggest `<Type as Trait>::{opaque}: 'static`.
} else if let Some(generics) = self.tcx.hir().get_generics(suggestion_scope) {
let pred = format!("{bound_kind}: {lt_name}");
let suggestion = format!("{} {}", generics.add_where_or_trailing_comma(), pred);
suggs.push((generics.tail_span_for_predicate_suggestion(), suggestion))
} else {
let consider = format!("{msg} `{bound_kind}: {sub}`...");
err.help(consider);
}
if !suggs.is_empty() {
err.multipart_suggestion_verbose(
msg,
suggs,
Applicability::MaybeIncorrect, // Issue #41966
);
}
}
err
}
pub fn suggest_name_region(
&self,
generic_param_scope: LocalDefId,
lifetime: Region<'tcx>,
add_lt_suggs: &mut Vec<(Span, String)>,
) -> String {
struct LifetimeReplaceVisitor<'tcx, 'a> {
tcx: TyCtxt<'tcx>,
needle: hir::LifetimeName,
new_lt: &'a str,
add_lt_suggs: &'a mut Vec<(Span, String)>,
}
impl<'hir, 'tcx> hir::intravisit::Visitor<'hir> for LifetimeReplaceVisitor<'tcx, '_> {
fn visit_lifetime(&mut self, lt: &'hir hir::Lifetime) {
if lt.res == self.needle {
let (pos, span) = lt.suggestion_position();
let new_lt = &self.new_lt;
let sugg = match pos {
hir::LifetimeSuggestionPosition::Normal => format!("{new_lt}"),
hir::LifetimeSuggestionPosition::Ampersand => format!("{new_lt} "),
hir::LifetimeSuggestionPosition::ElidedPath => format!("<{new_lt}>"),
hir::LifetimeSuggestionPosition::ElidedPathArgument => {
format!("{new_lt}, ")
}
hir::LifetimeSuggestionPosition::ObjectDefault => format!("+ {new_lt}"),
};
self.add_lt_suggs.push((span, sugg));
}
}
fn visit_ty(&mut self, ty: &'hir hir::Ty<'hir>) {
let hir::TyKind::OpaqueDef(item_id, _, _) = ty.kind else {
return hir::intravisit::walk_ty(self, ty);
};
let opaque_ty = self.tcx.hir().item(item_id).expect_opaque_ty();
if let Some(&(_, b)) =
opaque_ty.lifetime_mapping.iter().find(|&(a, _)| a.res == self.needle)
{
let prev_needle =
std::mem::replace(&mut self.needle, hir::LifetimeName::Param(b));
for bound in opaque_ty.bounds {
self.visit_param_bound(bound);
}
self.needle = prev_needle;
}
}
}
let (lifetime_def_id, lifetime_scope) =
match self.tcx.is_suitable_region(generic_param_scope, lifetime) {
Some(info) if !lifetime.has_name() => {
(info.bound_region.get_id().unwrap().expect_local(), info.def_id)
}
_ => return lifetime.get_name_or_anon().to_string(),
};
let new_lt = {
let generics = self.tcx.generics_of(lifetime_scope);
let mut used_names =
iter::successors(Some(generics), |g| g.parent.map(|p| self.tcx.generics_of(p)))
.flat_map(|g| &g.own_params)
.filter(|p| matches!(p.kind, ty::GenericParamDefKind::Lifetime))
.map(|p| p.name)
.collect::<Vec<_>>();
let hir_id = self.tcx.local_def_id_to_hir_id(lifetime_scope);
// consider late-bound lifetimes ...
used_names.extend(self.tcx.late_bound_vars(hir_id).into_iter().filter_map(
|p| match p {
ty::BoundVariableKind::Region(lt) => lt.get_name(),
_ => None,
},
));
(b'a'..=b'z')
.map(|c| format!("'{}", c as char))
.find(|candidate| !used_names.iter().any(|e| e.as_str() == candidate))
.unwrap_or("'lt".to_string())
};
let mut visitor = LifetimeReplaceVisitor {
tcx: self.tcx,
needle: hir::LifetimeName::Param(lifetime_def_id),
add_lt_suggs,
new_lt: &new_lt,
};
match self.tcx.expect_hir_owner_node(lifetime_scope) {
hir::OwnerNode::Item(i) => visitor.visit_item(i),
hir::OwnerNode::ForeignItem(i) => visitor.visit_foreign_item(i),
hir::OwnerNode::ImplItem(i) => visitor.visit_impl_item(i),
hir::OwnerNode::TraitItem(i) => visitor.visit_trait_item(i),
hir::OwnerNode::Crate(_) => bug!("OwnerNode::Crate doesn't not have generics"),
hir::OwnerNode::Synthetic => unreachable!(),
}
let ast_generics = self.tcx.hir().get_generics(lifetime_scope).unwrap();
let sugg = ast_generics
.span_for_lifetime_suggestion()
.map(|span| (span, format!("{new_lt}, ")))
.unwrap_or_else(|| (ast_generics.span, format!("<{new_lt}>")));
add_lt_suggs.push(sugg);
new_lt
}
fn report_sub_sup_conflict(
&self,
generic_param_scope: LocalDefId,
var_origin: RegionVariableOrigin,
sub_origin: SubregionOrigin<'tcx>,
sub_region: Region<'tcx>,
sup_origin: SubregionOrigin<'tcx>,
sup_region: Region<'tcx>,
) -> ErrorGuaranteed {
let mut err = self.report_inference_failure(var_origin);
note_and_explain_region(
self.tcx,
&mut err,
generic_param_scope,
"first, the lifetime cannot outlive ",
sup_region,
"...",
None,
);
debug!("report_sub_sup_conflict: var_origin={:?}", var_origin);
debug!("report_sub_sup_conflict: sub_region={:?}", sub_region);
debug!("report_sub_sup_conflict: sub_origin={:?}", sub_origin);
debug!("report_sub_sup_conflict: sup_region={:?}", sup_region);
debug!("report_sub_sup_conflict: sup_origin={:?}", sup_origin);
if let infer::Subtype(ref sup_trace) = sup_origin
&& let infer::Subtype(ref sub_trace) = sub_origin
&& let Some((sup_expected, sup_found, _)) = self.values_str(sup_trace.values)
&& let Some((sub_expected, sub_found, _)) = self.values_str(sub_trace.values)
&& sub_expected == sup_expected
&& sub_found == sup_found
{
note_and_explain_region(
self.tcx,
&mut err,
generic_param_scope,
"...but the lifetime must also be valid for ",
sub_region,
"...",
None,
);
err.span_note(
sup_trace.cause.span,
format!("...so that the {}", sup_trace.cause.as_requirement_str()),
);
err.note_expected_found(&"", sup_expected, &"", sup_found);
return if sub_region.is_error() | sup_region.is_error() {
err.delay_as_bug()
} else {
err.emit()
};
}
self.note_region_origin(&mut err, &sup_origin);
note_and_explain_region(
self.tcx,
&mut err,
generic_param_scope,
"but, the lifetime must be valid for ",
sub_region,
"...",
None,
);
self.note_region_origin(&mut err, &sub_origin);
if sub_region.is_error() | sup_region.is_error() { err.delay_as_bug() } else { err.emit() }
}
/// Determine whether an error associated with the given span and definition
/// should be treated as being caused by the implicit `From` conversion
/// within `?` desugaring.
@ -2792,55 +2008,6 @@ impl<'tcx> TypeRelation<TyCtxt<'tcx>> for SameTypeModuloInfer<'_, 'tcx> {
}
}
impl<'tcx> InferCtxt<'tcx> {
fn report_inference_failure(&self, var_origin: RegionVariableOrigin) -> Diag<'_> {
let br_string = |br: ty::BoundRegionKind| {
let mut s = match br {
ty::BrNamed(_, name) => name.to_string(),
_ => String::new(),
};
if !s.is_empty() {
s.push(' ');
}
s
};
let var_description = match var_origin {
infer::MiscVariable(_) => String::new(),
infer::PatternRegion(_) => " for pattern".to_string(),
infer::AddrOfRegion(_) => " for borrow expression".to_string(),
infer::Autoref(_) => " for autoref".to_string(),
infer::Coercion(_) => " for automatic coercion".to_string(),
infer::BoundRegion(_, br, infer::FnCall) => {
format!(" for lifetime parameter {}in function call", br_string(br))
}
infer::BoundRegion(_, br, infer::HigherRankedType) => {
format!(" for lifetime parameter {}in generic type", br_string(br))
}
infer::BoundRegion(_, br, infer::AssocTypeProjection(def_id)) => format!(
" for lifetime parameter {}in trait containing associated type `{}`",
br_string(br),
self.tcx.associated_item(def_id).name
),
infer::RegionParameterDefinition(_, name) => {
format!(" for lifetime parameter `{name}`")
}
infer::UpvarRegion(ref upvar_id, _) => {
let var_name = self.tcx.hir().name(upvar_id.var_path.hir_id);
format!(" for capture of `{var_name}` by closure")
}
infer::Nll(..) => bug!("NLL variable found in lexical phase"),
};
struct_span_code_err!(
self.dcx(),
var_origin.span(),
E0495,
"cannot infer an appropriate lifetime{} due to conflicting requirements",
var_description
)
}
}
pub enum FailureCode {
Error0317,
Error0580,

421
compiler/rustc_infer/src/infer/error_reporting/note.rs
View File

@ -1,421 +0,0 @@
use crate::errors::{
note_and_explain, FulfillReqLifetime, LfBoundNotSatisfied, OutlivesBound, OutlivesContent,
RefLongerThanData, RegionOriginNote, WhereClauseSuggestions,
};
use crate::fluent_generated as fluent;
use crate::infer::error_reporting::{note_and_explain_region, TypeErrCtxt};
use crate::infer::{self, SubregionOrigin};
use rustc_errors::{Diag, Subdiagnostic};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_middle::traits::ObligationCauseCode;
use rustc_middle::ty::error::TypeError;
use rustc_middle::ty::{self, IsSuggestable, Region, Ty};
use rustc_span::symbol::kw;
use super::ObligationCauseAsDiagArg;
impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
pub(super) fn note_region_origin(&self, err: &mut Diag<'_>, origin: &SubregionOrigin<'tcx>) {
match *origin {
infer::Subtype(ref trace) => RegionOriginNote::WithRequirement {
span: trace.cause.span,
requirement: ObligationCauseAsDiagArg(trace.cause.clone()),
expected_found: self.values_str(trace.values).map(|(e, f, _)| (e, f)),
}
.add_to_diag(err),
infer::Reborrow(span) => {
RegionOriginNote::Plain { span, msg: fluent::infer_reborrow }.add_to_diag(err)
}
infer::RelateObjectBound(span) => {
RegionOriginNote::Plain { span, msg: fluent::infer_relate_object_bound }
.add_to_diag(err);
}
infer::ReferenceOutlivesReferent(ty, span) => {
RegionOriginNote::WithName {
span,
msg: fluent::infer_reference_outlives_referent,
name: &self.ty_to_string(ty),
continues: false,
}
.add_to_diag(err);
}
infer::RelateParamBound(span, ty, opt_span) => {
RegionOriginNote::WithName {
span,
msg: fluent::infer_relate_param_bound,
name: &self.ty_to_string(ty),
continues: opt_span.is_some(),
}
.add_to_diag(err);
if let Some(span) = opt_span {
RegionOriginNote::Plain { span, msg: fluent::infer_relate_param_bound_2 }
.add_to_diag(err);
}
}
infer::RelateRegionParamBound(span) => {
RegionOriginNote::Plain { span, msg: fluent::infer_relate_region_param_bound }
.add_to_diag(err);
}
infer::CompareImplItemObligation { span, .. } => {
RegionOriginNote::Plain { span, msg: fluent::infer_compare_impl_item_obligation }
.add_to_diag(err);
}
infer::CheckAssociatedTypeBounds { ref parent, .. } => {
self.note_region_origin(err, parent);
}
infer::AscribeUserTypeProvePredicate(span) => {
RegionOriginNote::Plain {
span,
msg: fluent::infer_ascribe_user_type_prove_predicate,
}
.add_to_diag(err);
}
}
}
pub(super) fn report_concrete_failure(
&self,
generic_param_scope: LocalDefId,
origin: SubregionOrigin<'tcx>,
sub: Region<'tcx>,
sup: Region<'tcx>,
) -> Diag<'a> {
let mut err = match origin {
infer::Subtype(box trace) => {
let terr = TypeError::RegionsDoesNotOutlive(sup, sub);
let mut err = self.report_and_explain_type_error(trace, terr);
match (*sub, *sup) {
(ty::RePlaceholder(_), ty::RePlaceholder(_)) => {}
(ty::RePlaceholder(_), _) => {
note_and_explain_region(
self.tcx,
&mut err,
generic_param_scope,
"",
sup,
" doesn't meet the lifetime requirements",
None,
);
}
(_, ty::RePlaceholder(_)) => {
note_and_explain_region(
self.tcx,
&mut err,
generic_param_scope,
"the required lifetime does not necessarily outlive ",
sub,
"",
None,
);
}
_ => {
note_and_explain_region(
self.tcx,
&mut err,
generic_param_scope,
"",
sup,
"...",
None,
);
note_and_explain_region(
self.tcx,
&mut err,
generic_param_scope,
"...does not necessarily outlive ",
sub,
"",
None,
);
}
}
err
}
infer::Reborrow(span) => {
let reference_valid = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sub,
None,
note_and_explain::PrefixKind::RefValidFor,
note_and_explain::SuffixKind::Continues,
);
let content_valid = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sup,
None,
note_and_explain::PrefixKind::ContentValidFor,
note_and_explain::SuffixKind::Empty,
);
self.dcx().create_err(OutlivesContent {
span,
notes: reference_valid.into_iter().chain(content_valid).collect(),
})
}
infer::RelateObjectBound(span) => {
let object_valid = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sub,
None,
note_and_explain::PrefixKind::TypeObjValidFor,
note_and_explain::SuffixKind::Empty,
);
let pointer_valid = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sup,
None,
note_and_explain::PrefixKind::SourcePointerValidFor,
note_and_explain::SuffixKind::Empty,
);
self.dcx().create_err(OutlivesBound {
span,
notes: object_valid.into_iter().chain(pointer_valid).collect(),
})
}
infer::RelateParamBound(span, ty, opt_span) => {
let prefix = match *sub {
ty::ReStatic => note_and_explain::PrefixKind::TypeSatisfy,
_ => note_and_explain::PrefixKind::TypeOutlive,
};
let suffix = if opt_span.is_some() {
note_and_explain::SuffixKind::ReqByBinding
} else {
note_and_explain::SuffixKind::Empty
};
let note = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sub,
opt_span,
prefix,
suffix,
);
self.dcx().create_err(FulfillReqLifetime {
span,
ty: self.resolve_vars_if_possible(ty),
note,
})
}
infer::RelateRegionParamBound(span) => {
let param_instantiated = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sup,
None,
note_and_explain::PrefixKind::LfParamInstantiatedWith,
note_and_explain::SuffixKind::Empty,
);
let param_must_outlive = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sub,
None,
note_and_explain::PrefixKind::LfParamMustOutlive,
note_and_explain::SuffixKind::Empty,
);
self.dcx().create_err(LfBoundNotSatisfied {
span,
notes: param_instantiated.into_iter().chain(param_must_outlive).collect(),
})
}
infer::ReferenceOutlivesReferent(ty, span) => {
let pointer_valid = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sub,
None,
note_and_explain::PrefixKind::PointerValidFor,
note_and_explain::SuffixKind::Empty,
);
let data_valid = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sup,
None,
note_and_explain::PrefixKind::DataValidFor,
note_and_explain::SuffixKind::Empty,
);
self.dcx().create_err(RefLongerThanData {
span,
ty: self.resolve_vars_if_possible(ty),
notes: pointer_valid.into_iter().chain(data_valid).collect(),
})
}
infer::CompareImplItemObligation { span, impl_item_def_id, trait_item_def_id } => {
let mut err = self.infcx.report_extra_impl_obligation(
span,
impl_item_def_id,
trait_item_def_id,
&format!("`{sup}: {sub}`"),
);
// We should only suggest rewriting the `where` clause if the predicate is within that `where` clause
if let Some(generics) = self.tcx.hir().get_generics(impl_item_def_id)
&& generics.where_clause_span.contains(span)
{
self.suggest_copy_trait_method_bounds(
trait_item_def_id,
impl_item_def_id,
&mut err,
);
}
err
}
infer::CheckAssociatedTypeBounds { impl_item_def_id, trait_item_def_id, parent } => {
let mut err = self.report_concrete_failure(generic_param_scope, *parent, sub, sup);
// Don't mention the item name if it's an RPITIT, since that'll just confuse
// folks.
if !self.tcx.is_impl_trait_in_trait(impl_item_def_id.to_def_id()) {
let trait_item_span = self.tcx.def_span(trait_item_def_id);
let item_name = self.tcx.item_name(impl_item_def_id.to_def_id());
err.span_label(
trait_item_span,
format!("definition of `{item_name}` from trait"),
);
}
self.suggest_copy_trait_method_bounds(
trait_item_def_id,
impl_item_def_id,
&mut err,
);
err
}
infer::AscribeUserTypeProvePredicate(span) => {
let instantiated = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sup,
None,
note_and_explain::PrefixKind::LfInstantiatedWith,
note_and_explain::SuffixKind::Empty,
);
let must_outlive = note_and_explain::RegionExplanation::new(
self.tcx,
generic_param_scope,
sub,
None,
note_and_explain::PrefixKind::LfMustOutlive,
note_and_explain::SuffixKind::Empty,
);
self.dcx().create_err(LfBoundNotSatisfied {
span,
notes: instantiated.into_iter().chain(must_outlive).collect(),
})
}
};
if sub.is_error() || sup.is_error() {
err.downgrade_to_delayed_bug();
}
err
}
pub fn suggest_copy_trait_method_bounds(
&self,
trait_item_def_id: DefId,
impl_item_def_id: LocalDefId,
err: &mut Diag<'_>,
) {
// FIXME(compiler-errors): Right now this is only being used for region
// predicate mismatches. Ideally, we'd use it for *all* predicate mismatches,
// but right now it's not really very smart when it comes to implicit `Sized`
// predicates and bounds on the trait itself.
let Some(impl_def_id) = self.tcx.associated_item(impl_item_def_id).impl_container(self.tcx)
else {
return;
};
let Some(trait_ref) = self.tcx.impl_trait_ref(impl_def_id) else {
return;
};
let trait_args = trait_ref
.instantiate_identity()
// Replace the explicit self type with `Self` for better suggestion rendering
.with_self_ty(self.tcx, Ty::new_param(self.tcx, 0, kw::SelfUpper))
.args;
let trait_item_args = ty::GenericArgs::identity_for_item(self.tcx, impl_item_def_id)
.rebase_onto(self.tcx, impl_def_id, trait_args);
let Ok(trait_predicates) =
self.tcx
.explicit_predicates_of(trait_item_def_id)
.instantiate_own(self.tcx, trait_item_args)
.map(|(pred, _)| {
if pred.is_suggestable(self.tcx, false) {
Ok(pred.to_string())
} else {
Err(())
}
})
.collect::<Result<Vec<_>, ()>>()
else {
return;
};
let Some(generics) = self.tcx.hir().get_generics(impl_item_def_id) else {
return;
};
let suggestion = if trait_predicates.is_empty() {
WhereClauseSuggestions::Remove { span: generics.where_clause_span }
} else {
let space = if generics.where_clause_span.is_empty() { " " } else { "" };
WhereClauseSuggestions::CopyPredicates {
span: generics.where_clause_span,
space,
trait_predicates: trait_predicates.join(", "),
}
};
err.subdiagnostic(suggestion);
}
pub(super) fn report_placeholder_failure(
&self,
generic_param_scope: LocalDefId,
placeholder_origin: SubregionOrigin<'tcx>,
sub: Region<'tcx>,
sup: Region<'tcx>,
) -> Diag<'a> {
// I can't think how to do better than this right now. -nikomatsakis
debug!(?placeholder_origin, ?sub, ?sup, "report_placeholder_failure");
match placeholder_origin {
infer::Subtype(box ref trace)
if matches!(
&trace.cause.code().peel_derives(),
ObligationCauseCode::WhereClause(..)
| ObligationCauseCode::WhereClauseInExpr(..)
) =>
{
// Hack to get around the borrow checker because trace.cause has an `Rc`.
if let ObligationCauseCode::WhereClause(_, span)
| ObligationCauseCode::WhereClauseInExpr(_, span, ..) =
&trace.cause.code().peel_derives()
&& !span.is_dummy()
{
let span = *span;
self.report_concrete_failure(generic_param_scope, placeholder_origin, sub, sup)
.with_span_note(span, "the lifetime requirement is introduced here")
} else {
unreachable!(
"control flow ensures we have a `BindingObligation` or `WhereClauseInExpr` here..."
)
}
}
infer::Subtype(box trace) => {
let terr = TypeError::RegionsPlaceholderMismatch;
return self.report_and_explain_type_error(trace, terr);
}
_ => {
return self.report_concrete_failure(
generic_param_scope,
placeholder_origin,
sub,
sup,
);
}
}
}
}

1259
compiler/rustc_infer/src/infer/error_reporting/region.rs Normal file
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