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Auto merge of #69242 - cjgillot:object_violations, r=Zoxc 

Querify object_safety_violations.

Split from #69076

r? @Zoxc
This commit is contained in:
bors 2020-02-21 20:25:50 +00:00
parent 8aa9d2014f 310f4707e5
commit 1d7e818747
12 changed files with 153 additions and 156 deletions
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2
src/librustc/query/mod.rs
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@ -661,7 +661,7 @@ rustc_queries! {
desc { |tcx| "building specialization graph of trait `{}`", tcx.def_path_str(key) }
cache_on_disk_if { true }
}
query is_object_safe(key: DefId) -> bool {
query object_safety_violations(key: DefId) -> Vec<traits::ObjectSafetyViolation> {
desc { |tcx| "determine object safety of trait `{}`", tcx.def_path_str(key) }
}

132
src/librustc/traits/mod.rs
View File

@ -16,8 +16,10 @@ use crate::ty::{self, AdtKind, List, Ty, TyCtxt};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_span::{Span, DUMMY_SP};
use smallvec::SmallVec;
use syntax::ast;
use std::borrow::Cow;
use std::fmt::Debug;
use std::rc::Rc;
@ -737,3 +739,133 @@ where
tcx: TyCtxt<'tcx>,
) -> Option<Self::LiftedLiteral>;
}
#[derive(Clone, Debug, PartialEq, Eq, Hash, HashStable)]
pub enum ObjectSafetyViolation {
/// `Self: Sized` declared on the trait.
SizedSelf(SmallVec<[Span; 1]>),
/// Supertrait reference references `Self` an in illegal location
/// (e.g., `trait Foo : Bar<Self>`).
SupertraitSelf(SmallVec<[Span; 1]>),
/// Method has something illegal.
Method(ast::Name, MethodViolationCode, Span),
/// Associated const.
AssocConst(ast::Name, Span),
}
impl ObjectSafetyViolation {
pub fn error_msg(&self) -> Cow<'static, str> {
match *self {
ObjectSafetyViolation::SizedSelf(_) => "it requires `Self: Sized`".into(),
ObjectSafetyViolation::SupertraitSelf(ref spans) => {
if spans.iter().any(|sp| *sp != DUMMY_SP) {
"it uses `Self` as a type parameter in this".into()
} else {
"it cannot use `Self` as a type parameter in a supertrait or `where`-clause"
.into()
}
}
ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(_), _) => {
format!("associated function `{}` has no `self` parameter", name).into()
}
ObjectSafetyViolation::Method(
name,
MethodViolationCode::ReferencesSelfInput(_),
DUMMY_SP,
) => format!("method `{}` references the `Self` type in its parameters", name).into(),
ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelfInput(_), _) => {
format!("method `{}` references the `Self` type in this parameter", name).into()
}
ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelfOutput, _) => {
format!("method `{}` references the `Self` type in its return type", name).into()
}
ObjectSafetyViolation::Method(
name,
MethodViolationCode::WhereClauseReferencesSelf,
_,
) => {
format!("method `{}` references the `Self` type in its `where` clause", name).into()
}
ObjectSafetyViolation::Method(name, MethodViolationCode::Generic, _) => {
format!("method `{}` has generic type parameters", name).into()
}
ObjectSafetyViolation::Method(name, MethodViolationCode::UndispatchableReceiver, _) => {
format!("method `{}`'s `self` parameter cannot be dispatched on", name).into()
}
ObjectSafetyViolation::AssocConst(name, DUMMY_SP) => {
format!("it contains associated `const` `{}`", name).into()
}
ObjectSafetyViolation::AssocConst(..) => "it contains this associated `const`".into(),
}
}
pub fn solution(&self) -> Option<(String, Option<(String, Span)>)> {
Some(match *self {
ObjectSafetyViolation::SizedSelf(_) | ObjectSafetyViolation::SupertraitSelf(_) => {
return None;
}
ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(sugg), _) => (
format!(
"consider turning `{}` into a method by giving it a `&self` argument or \
constraining it so it does not apply to trait objects",
name
),
sugg.map(|(sugg, sp)| (sugg.to_string(), sp)),
),
ObjectSafetyViolation::Method(
name,
MethodViolationCode::UndispatchableReceiver,
span,
) => (
format!("consider changing method `{}`'s `self` parameter to be `&self`", name)
.into(),
Some(("&Self".to_string(), span)),
),
ObjectSafetyViolation::AssocConst(name, _)
| ObjectSafetyViolation::Method(name, ..) => {
(format!("consider moving `{}` to another trait", name), None)
}
})
}
pub fn spans(&self) -> SmallVec<[Span; 1]> {
// When `span` comes from a separate crate, it'll be `DUMMY_SP`. Treat it as `None` so
// diagnostics use a `note` instead of a `span_label`.
match self {
ObjectSafetyViolation::SupertraitSelf(spans)
| ObjectSafetyViolation::SizedSelf(spans) => spans.clone(),
ObjectSafetyViolation::AssocConst(_, span)
| ObjectSafetyViolation::Method(_, _, span)
if *span != DUMMY_SP =>
{
smallvec![*span]
}
_ => smallvec![],
}
}
}
/// Reasons a method might not be object-safe.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
pub enum MethodViolationCode {
/// e.g., `fn foo()`
StaticMethod(Option<(&'static str, Span)>),
/// e.g., `fn foo(&self, x: Self)`
ReferencesSelfInput(usize),
/// e.g., `fn foo(&self) -> Self`
ReferencesSelfOutput,
/// e.g., `fn foo(&self) where Self: Clone`
WhereClauseReferencesSelf,
/// e.g., `fn foo<A>()`
Generic,
/// the method's receiver (`self` argument) can't be dispatched on
UndispatchableReceiver,
}

4
src/librustc/ty/mod.rs
View File

@ -3081,6 +3081,10 @@ impl<'tcx> TyCtxt<'tcx> {
};
(ident, scope)
}
pub fn is_object_safe(self, key: DefId) -> bool {
self.object_safety_violations(key).is_empty()
}
}
#[derive(Clone, HashStable)]

2
src/librustc_incremental/persist/dirty_clean.rs
View File

@ -78,7 +78,7 @@ const BASE_STRUCT: &[&str] =
const BASE_TRAIT_DEF: &[&str] = &[
label_strs::associated_item_def_ids,
label_strs::generics_of,
label_strs::is_object_safe,
label_strs::object_safety_violations,
label_strs::predicates_of,
label_strs::specialization_graph_of,
label_strs::trait_def,

3
src/librustc_infer/infer/error_reporting/mod.rs
View File

@ -52,7 +52,6 @@ use super::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TypeTrace, ValuePa
use crate::infer::opaque_types;
use crate::infer::{self, SuppressRegionErrors};
use crate::traits::error_reporting::report_object_safety_error;
use crate::traits::object_safety_violations;
use crate::traits::{
IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode,
};
@ -1618,7 +1617,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
let failure_code = trace.cause.as_failure_code(terr);
let mut diag = match failure_code {
FailureCode::Error0038(did) => {
let violations = object_safety_violations(self.tcx, did);
let violations = self.tcx.object_safety_violations(did);
report_object_safety_error(self.tcx, span, did, violations)
}
FailureCode::Error0317(failure_str) => {

5
src/librustc_infer/traits/error_reporting/mod.rs
View File

@ -12,7 +12,6 @@ use super::{
use crate::infer::error_reporting::{TyCategory, TypeAnnotationNeeded as ErrorCode};
use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use crate::infer::{self, InferCtxt, TyCtxtInferExt};
use crate::traits::object_safety_violations;
use rustc::mir::interpret::ErrorHandled;
use rustc::session::DiagnosticMessageId;
use rustc::ty::error::ExpectedFound;
@ -748,7 +747,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
}
ty::Predicate::ObjectSafe(trait_def_id) => {
let violations = object_safety_violations(self.tcx, trait_def_id);
let violations = self.tcx.object_safety_violations(trait_def_id);
report_object_safety_error(self.tcx, span, trait_def_id, violations)
}
@ -912,7 +911,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
}
TraitNotObjectSafe(did) => {
let violations = object_safety_violations(self.tcx, did);
let violations = self.tcx.object_safety_violations(did);
report_object_safety_error(self.tcx, span, did, violations)
}

3
src/librustc_infer/traits/error_reporting/suggestions.rs
View File

@ -5,7 +5,6 @@ use super::{
use crate::infer::InferCtxt;
use crate::traits::error_reporting::suggest_constraining_type_param;
use crate::traits::object_safety::object_safety_violations;
use rustc::ty::TypeckTables;
use rustc::ty::{self, AdtKind, DefIdTree, ToPredicate, Ty, TyCtxt, TypeFoldable, WithConstness};
@ -587,7 +586,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
// If the `dyn Trait` is not object safe, do not suggest `Box<dyn Trait>`.
predicates
.principal_def_id()
.map_or(true, |def_id| object_safety_violations(self.tcx, def_id).is_empty())
.map_or(true, |def_id| self.tcx.object_safety_violations(def_id).is_empty())
}
// We only want to suggest `impl Trait` to `dyn Trait`s.
// For example, `fn foo() -> str` needs to be filtered out.

3
src/librustc_infer/traits/mod.rs
View File

@ -47,7 +47,6 @@ pub use self::engine::{TraitEngine, TraitEngineExt};
pub use self::fulfill::{FulfillmentContext, PendingPredicateObligation};
pub use self::object_safety::astconv_object_safety_violations;
pub use self::object_safety::is_vtable_safe_method;
pub use self::object_safety::object_safety_violations;
pub use self::object_safety::MethodViolationCode;
pub use self::object_safety::ObjectSafetyViolation;
pub use self::on_unimplemented::{OnUnimplementedDirective, OnUnimplementedNote};
@ -636,8 +635,8 @@ impl<'tcx> TraitObligation<'tcx> {
}
pub fn provide(providers: &mut ty::query::Providers<'_>) {
object_safety::provide(providers);
*providers = ty::query::Providers {
is_object_safe: object_safety::is_object_safe_provider,
specialization_graph_of: specialize::specialization_graph_provider,
specializes: specialize::specializes,
codegen_fulfill_obligation: codegen::codegen_fulfill_obligation,

147
src/librustc_infer/traits/object_safety.rs
View File

@ -19,142 +19,12 @@ use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_session::lint::builtin::WHERE_CLAUSES_OBJECT_SAFETY;
use rustc_span::symbol::Symbol;
use rustc_span::{Span, DUMMY_SP};
use smallvec::{smallvec, SmallVec};
use syntax::ast;
use rustc_span::Span;
use smallvec::SmallVec;
use std::borrow::Cow;
use std::iter::{self};
use std::iter;
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum ObjectSafetyViolation {
/// `Self: Sized` declared on the trait.
SizedSelf(SmallVec<[Span; 1]>),
/// Supertrait reference references `Self` an in illegal location
/// (e.g., `trait Foo : Bar<Self>`).
SupertraitSelf(SmallVec<[Span; 1]>),
/// Method has something illegal.
Method(ast::Name, MethodViolationCode, Span),
/// Associated const.
AssocConst(ast::Name, Span),
}
impl ObjectSafetyViolation {
pub fn error_msg(&self) -> Cow<'static, str> {
match *self {
ObjectSafetyViolation::SizedSelf(_) => "it requires `Self: Sized`".into(),
ObjectSafetyViolation::SupertraitSelf(ref spans) => {
if spans.iter().any(|sp| *sp != DUMMY_SP) {
"it uses `Self` as a type parameter in this".into()
} else {
"it cannot use `Self` as a type parameter in a supertrait or `where`-clause"
.into()
}
}
ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(_), _) => {
format!("associated function `{}` has no `self` parameter", name).into()
}
ObjectSafetyViolation::Method(
name,
MethodViolationCode::ReferencesSelfInput(_),
DUMMY_SP,
) => format!("method `{}` references the `Self` type in its parameters", name).into(),
ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelfInput(_), _) => {
format!("method `{}` references the `Self` type in this parameter", name).into()
}
ObjectSafetyViolation::Method(name, MethodViolationCode::ReferencesSelfOutput, _) => {
format!("method `{}` references the `Self` type in its return type", name).into()
}
ObjectSafetyViolation::Method(
name,
MethodViolationCode::WhereClauseReferencesSelf,
_,
) => {
format!("method `{}` references the `Self` type in its `where` clause", name).into()
}
ObjectSafetyViolation::Method(name, MethodViolationCode::Generic, _) => {
format!("method `{}` has generic type parameters", name).into()
}
ObjectSafetyViolation::Method(name, MethodViolationCode::UndispatchableReceiver, _) => {
format!("method `{}`'s `self` parameter cannot be dispatched on", name).into()
}
ObjectSafetyViolation::AssocConst(name, DUMMY_SP) => {
format!("it contains associated `const` `{}`", name).into()
}
ObjectSafetyViolation::AssocConst(..) => "it contains this associated `const`".into(),
}
}
pub fn solution(&self) -> Option<(String, Option<(String, Span)>)> {
Some(match *self {
ObjectSafetyViolation::SizedSelf(_) | ObjectSafetyViolation::SupertraitSelf(_) => {
return None;
}
ObjectSafetyViolation::Method(name, MethodViolationCode::StaticMethod(sugg), _) => (
format!(
"consider turning `{}` into a method by giving it a `&self` argument or \
constraining it so it does not apply to trait objects",
name
),
sugg.map(|(sugg, sp)| (sugg.to_string(), sp)),
),
ObjectSafetyViolation::Method(
name,
MethodViolationCode::UndispatchableReceiver,
span,
) => (
format!("consider changing method `{}`'s `self` parameter to be `&self`", name)
.into(),
Some(("&Self".to_string(), span)),
),
ObjectSafetyViolation::AssocConst(name, _)
| ObjectSafetyViolation::Method(name, ..) => {
(format!("consider moving `{}` to another trait", name), None)
}
})
}
pub fn spans(&self) -> SmallVec<[Span; 1]> {
// When `span` comes from a separate crate, it'll be `DUMMY_SP`. Treat it as `None` so
// diagnostics use a `note` instead of a `span_label`.
match self {
ObjectSafetyViolation::SupertraitSelf(spans)
| ObjectSafetyViolation::SizedSelf(spans) => spans.clone(),
ObjectSafetyViolation::AssocConst(_, span)
| ObjectSafetyViolation::Method(_, _, span)
if *span != DUMMY_SP =>
{
smallvec![*span]
}
_ => smallvec![],
}
}
}
/// Reasons a method might not be object-safe.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum MethodViolationCode {
/// e.g., `fn foo()`
StaticMethod(Option<(&'static str, Span)>),
/// e.g., `fn foo(&self, x: Self)`
ReferencesSelfInput(usize),
/// e.g., `fn foo(&self) -> Self`
ReferencesSelfOutput,
/// e.g., `fn foo(&self) where Self: Clone`
WhereClauseReferencesSelf,
/// e.g., `fn foo<A>()`
Generic,
/// the method's receiver (`self` argument) can't be dispatched on
UndispatchableReceiver,
}
pub use crate::traits::{MethodViolationCode, ObjectSafetyViolation};
/// Returns the object safety violations that affect
/// astconv -- currently, `Self` in supertraits. This is needed
@ -176,10 +46,7 @@ pub fn astconv_object_safety_violations(
violations
}
pub fn object_safety_violations(
tcx: TyCtxt<'_>,
trait_def_id: DefId,
) -> Vec<ObjectSafetyViolation> {
fn object_safety_violations(tcx: TyCtxt<'_>, trait_def_id: DefId) -> Vec<ObjectSafetyViolation> {
debug_assert!(tcx.generics_of(trait_def_id).has_self);
debug!("object_safety_violations: {:?}", trait_def_id);
@ -905,6 +772,6 @@ fn contains_illegal_self_type_reference<'tcx>(
error
}
pub(super) fn is_object_safe_provider(tcx: TyCtxt<'_>, trait_def_id: DefId) -> bool {
object_safety_violations(tcx, trait_def_id).is_empty()
pub fn provide(providers: &mut ty::query::Providers<'_>) {
*providers = ty::query::Providers { object_safety_violations, ..*providers };
}

3
src/librustc_typeck/check/cast.rs
View File

@ -45,7 +45,6 @@ use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
use rustc_hir as hir;
use rustc_infer::traits;
use rustc_infer::traits::error_reporting::report_object_safety_error;
use rustc_infer::traits::object_safety_violations;
use rustc_span::Span;
use syntax::ast;
@ -517,7 +516,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
}
fn report_object_unsafe_cast(&self, fcx: &FnCtxt<'a, 'tcx>, did: DefId) {
let violations = object_safety_violations(fcx.tcx, did);
let violations = fcx.tcx.object_safety_violations(did);
let mut err = report_object_safety_error(fcx.tcx, self.cast_span, did, violations);
err.note(&format!("required by cast to type '{}'", fcx.ty_to_string(self.cast_ty)));
err.emit();

3
src/librustc_typeck/check/coercion.rs
View File

@ -66,7 +66,6 @@ use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use rustc_infer::infer::{Coercion, InferOk, InferResult};
use rustc_infer::traits::object_safety_violations;
use rustc_infer::traits::{self, ObligationCause, ObligationCauseCode};
use rustc_span::symbol::sym;
use rustc_span::{self, Span};
@ -1404,7 +1403,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
// Are of this `impl Trait`'s traits object safe?
is_object_safe = bounds.iter().all(|bound| {
bound.trait_def_id().map_or(false, |def_id| {
object_safety_violations(fcx.tcx, def_id).is_empty()
fcx.tcx.object_safety_violations(def_id).is_empty()
})
})
}

2
src/librustc_typeck/check/wfcheck.rs
View File

@ -223,7 +223,7 @@ fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem
_ => {}
}
if !trait_should_be_self.is_empty() {
if rustc_infer::traits::object_safety_violations(tcx, trait_def_id).is_empty() {
if tcx.object_safety_violations(trait_def_id).is_empty() {
return;
}
let sugg = trait_should_be_self.iter().map(|span| (*span, "Self".to_string())).collect();