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Split astconv's error report code in check functions to mod errors.
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Move some error report codes to mod `astconv/errors.rs`
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@surechen
surechen committed Mar 22, 2024
1 parent 6e1f7b5 commit 83cafab
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Showing 4 changed files with 185 additions and 133 deletions.
159 changes: 158 additions & 1 deletion compiler/rustc_hir_analysis/src/astconv/errors.rs
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
use crate::astconv::AstConv;
use crate::errors::TraitObjectDeclaredWithNoTraits;
use crate::errors::{
self, AssocTypeBindingNotAllowed, ManualImplementation, MissingTypeParams,
ParenthesizedFnTraitExpansion,
Expand All @@ -8,6 +9,7 @@ use crate::traits::error_reporting::report_object_safety_error;
use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
use rustc_data_structures::sorted_map::SortedMap;
use rustc_data_structures::unord::UnordMap;
use rustc_errors::MultiSpan;
use rustc_errors::{
codes::*, pluralize, struct_span_code_err, Applicability, Diag, ErrorGuaranteed,
};
Expand All @@ -16,11 +18,22 @@ use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_infer::traits::FulfillmentError;
use rustc_middle::query::Key;
use rustc_middle::ty::{self, suggest_constraining_type_param, Ty, TyCtxt, TypeVisitableExt};
use rustc_middle::ty::{Binder, TraitRef};
use rustc_session::parse::feature_err;
use rustc_span::edit_distance::find_best_match_for_name;
use rustc_span::symbol::{sym, Ident};
use rustc_span::{Span, Symbol, DUMMY_SP};
use rustc_trait_selection::traits::object_safety_violations_for_assoc_item;
use rustc_trait_selection::traits::{
object_safety_violations_for_assoc_item, TraitAliasExpansionInfo,
};

#[derive(PartialEq, Eq, Hash)]
pub enum ProhibitGenericsArg {
Lifetime,
Type,
Const,
Infer,
}

impl<'tcx> dyn AstConv<'tcx> + '_ {
/// On missing type parameters, emit an E0393 error and provide a structured suggestion using
Expand Down Expand Up @@ -1024,6 +1037,150 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
Ok(())
}
}

pub fn report_prohibit_generics_error<'a>(
&self,
segments: impl Iterator<Item = &'a hir::PathSegment<'a>> + Clone,
prohibit_args: FxIndexSet<ProhibitGenericsArg>,
extend: impl Fn(&mut Diag<'_>),
) {
let types_and_spans: Vec<_> = segments
.clone()
.flat_map(|segment| {
if segment.args().args.is_empty() {
None
} else {
Some((
match segment.res {
hir::def::Res::PrimTy(ty) => {
format!("{} `{}`", segment.res.descr(), ty.name())
}
hir::def::Res::Def(_, def_id)
if let Some(name) = self.tcx().opt_item_name(def_id) =>
{
format!("{} `{name}`", segment.res.descr())
}
hir::def::Res::Err => "this type".to_string(),
_ => segment.res.descr().to_string(),
},
segment.ident.span,
))
}
})
.collect();
let this_type = match &types_and_spans[..] {
[.., _, (last, _)] => format!(
"{} and {last}",
types_and_spans[..types_and_spans.len() - 1]
.iter()
.map(|(x, _)| x.as_str())
.intersperse(", ")
.collect::<String>()
),
[(only, _)] => only.to_string(),
[] => "this type".to_string(),
};

let arg_spans: Vec<Span> = segments
.clone()
.flat_map(|segment| segment.args().args)
.map(|arg| arg.span())
.collect();

let mut kinds = Vec::with_capacity(4);
prohibit_args.iter().for_each(|arg| match arg {
ProhibitGenericsArg::Lifetime => kinds.push("lifetime"),
ProhibitGenericsArg::Type => kinds.push("type"),
ProhibitGenericsArg::Const => kinds.push("const"),
ProhibitGenericsArg::Infer => kinds.push("generic"),
});

let (kind, s) = match kinds[..] {
[.., _, last] => (
format!(
"{} and {last}",
kinds[..kinds.len() - 1]
.iter()
.map(|&x| x)
.intersperse(", ")
.collect::<String>()
),
"s",
),
[only] => (only.to_string(), ""),
[] => unreachable!("expected at least one generic to prohibit"),
};
let last_span = *arg_spans.last().unwrap();
let span: MultiSpan = arg_spans.into();
let mut err = struct_span_code_err!(
self.tcx().dcx(),
span,
E0109,
"{kind} arguments are not allowed on {this_type}",
);
err.span_label(last_span, format!("{kind} argument{s} not allowed"));
for (what, span) in types_and_spans {
err.span_label(span, format!("not allowed on {what}"));
}
extend(&mut err);
self.set_tainted_by_errors(err.emit());
}

pub fn report_trait_object_addition_traits_error(
&self,
span: Span,
trait_bounds: &Vec<(Binder<'tcx, TraitRef<'tcx>>, Span)>,
auto_traits: &Vec<TraitAliasExpansionInfo<'_>>,
regular_traits: &Vec<TraitAliasExpansionInfo<'_>>,
) -> Option<ErrorGuaranteed> {
let tcx = self.tcx();
if regular_traits.len() > 1 {
let first_trait = &regular_traits[0];
let additional_trait = &regular_traits[1];
let mut err = struct_span_code_err!(
tcx.dcx(),
additional_trait.bottom().1,
E0225,
"only auto traits can be used as additional traits in a trait object"
);
additional_trait.label_with_exp_info(
&mut err,
"additional non-auto trait",
"additional use",
);
first_trait.label_with_exp_info(&mut err, "first non-auto trait", "first use");
err.help(format!(
"consider creating a new trait with all of these as supertraits and using that \
trait here instead: `trait NewTrait: {} {{}}`",
regular_traits
.iter()
// FIXME: This should `print_sugared`, but also needs to integrate projection bounds...
.map(|t| t.trait_ref().print_only_trait_path().to_string())
.collect::<Vec<_>>()
.join(" + "),
));
err.note(
"auto-traits like `Send` and `Sync` are traits that have special properties; \
for more information on them, visit \
<https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>",
);
self.set_tainted_by_errors(err.emit());
}

if regular_traits.is_empty() && auto_traits.is_empty() {
let trait_alias_span = trait_bounds
.iter()
.map(|&(trait_ref, _)| trait_ref.def_id())
.find(|&trait_ref| tcx.is_trait_alias(trait_ref))
.map(|trait_ref| tcx.def_span(trait_ref));
let reported =
tcx.dcx().emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span });
self.set_tainted_by_errors(reported);
return Some(reported);
}

None
}
}

/// Emits an error regarding forbidden type binding associations
Expand Down
105 changes: 13 additions & 92 deletions compiler/rustc_hir_analysis/src/astconv/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,15 +8,15 @@ pub mod generics;
mod lint;
mod object_safety;

use crate::astconv::errors::prohibit_assoc_ty_binding;
use crate::astconv::errors::{prohibit_assoc_ty_binding, ProhibitGenericsArg};
use crate::astconv::generics::{check_generic_arg_count, create_args_for_parent_generic_args};
use crate::bounds::Bounds;
use crate::collect::HirPlaceholderCollector;
use crate::errors::AmbiguousLifetimeBound;
use crate::middle::resolve_bound_vars as rbv;
use crate::require_c_abi_if_c_variadic;
use rustc_ast::TraitObjectSyntax;
use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
use rustc_errors::{
codes::*, struct_span_code_err, Applicability, Diag, ErrorGuaranteed, FatalError, MultiSpan,
};
Expand Down Expand Up @@ -1578,98 +1578,19 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
segments: impl Iterator<Item = &'a hir::PathSegment<'a>> + Clone,
extend: impl Fn(&mut Diag<'_>),
) -> bool {
let args = segments.clone().flat_map(|segment| segment.args().args);

let (lt, ty, ct, inf) =
args.clone().fold((false, false, false, false), |(lt, ty, ct, inf), arg| match arg {
hir::GenericArg::Lifetime(_) => (true, ty, ct, inf),
hir::GenericArg::Type(_) => (lt, true, ct, inf),
hir::GenericArg::Const(_) => (lt, ty, true, inf),
hir::GenericArg::Infer(_) => (lt, ty, ct, true),
});
let mut emitted = false;
if lt || ty || ct || inf {
let types_and_spans: Vec<_> = segments
.clone()
.flat_map(|segment| {
if segment.args().args.is_empty() {
None
} else {
Some((
match segment.res {
Res::PrimTy(ty) => {
format!("{} `{}`", segment.res.descr(), ty.name())
}
Res::Def(_, def_id)
if let Some(name) = self.tcx().opt_item_name(def_id) =>
{
format!("{} `{name}`", segment.res.descr())
}
Res::Err => "this type".to_string(),
_ => segment.res.descr().to_string(),
},
segment.ident.span,
))
}
})
.collect();
let this_type = match &types_and_spans[..] {
[.., _, (last, _)] => format!(
"{} and {last}",
types_and_spans[..types_and_spans.len() - 1]
.iter()
.map(|(x, _)| x.as_str())
.intersperse(", ")
.collect::<String>()
),
[(only, _)] => only.to_string(),
[] => "this type".to_string(),
let mut prohibit_args = FxIndexSet::default();
segments.clone().flat_map(|segment| segment.args().args).for_each(|arg| {
match arg {
hir::GenericArg::Lifetime(_) => prohibit_args.insert(ProhibitGenericsArg::Lifetime),
hir::GenericArg::Type(_) => prohibit_args.insert(ProhibitGenericsArg::Type),
hir::GenericArg::Const(_) => prohibit_args.insert(ProhibitGenericsArg::Const),
hir::GenericArg::Infer(_) => prohibit_args.insert(ProhibitGenericsArg::Infer),
};
});

let arg_spans: Vec<Span> = args.map(|arg| arg.span()).collect();

let mut kinds = Vec::with_capacity(4);
if lt {
kinds.push("lifetime");
}
if ty {
kinds.push("type");
}
if ct {
kinds.push("const");
}
if inf {
kinds.push("generic");
}
let (kind, s) = match kinds[..] {
[.., _, last] => (
format!(
"{} and {last}",
kinds[..kinds.len() - 1]
.iter()
.map(|&x| x)
.intersperse(", ")
.collect::<String>()
),
"s",
),
[only] => (only.to_string(), ""),
[] => unreachable!("expected at least one generic to prohibit"),
};
let last_span = *arg_spans.last().unwrap();
let span: MultiSpan = arg_spans.into();
let mut err = struct_span_code_err!(
self.tcx().dcx(),
span,
E0109,
"{kind} arguments are not allowed on {this_type}",
);
err.span_label(last_span, format!("{kind} argument{s} not allowed"));
for (what, span) in types_and_spans {
err.span_label(span, format!("not allowed on {what}"));
}
extend(&mut err);
self.set_tainted_by_errors(err.emit());
let mut emitted = false;
if !prohibit_args.is_empty() {
self.report_prohibit_generics_error(segments.clone(), prohibit_args, extend);
emitted = true;
}

Expand Down
52 changes: 13 additions & 39 deletions compiler/rustc_hir_analysis/src/astconv/object_safety.rs
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
use crate::astconv::{GenericArgCountMismatch, GenericArgCountResult, OnlySelfBounds};
use crate::bounds::Bounds;
use crate::errors::TraitObjectDeclaredWithNoTraits;
use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
use rustc_errors::{codes::*, struct_span_code_err};
use rustc_hir as hir;
Expand Down Expand Up @@ -84,48 +83,23 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
let (mut auto_traits, regular_traits): (Vec<_>, Vec<_>) =
expanded_traits.partition(|i| tcx.trait_is_auto(i.trait_ref().def_id()));
if regular_traits.len() > 1 {
let first_trait = &regular_traits[0];
let additional_trait = &regular_traits[1];
let mut err = struct_span_code_err!(
tcx.dcx(),
additional_trait.bottom().1,
E0225,
"only auto traits can be used as additional traits in a trait object"
self.report_trait_object_addition_traits_error(
span,
&trait_bounds,
&auto_traits,
&regular_traits,
);
additional_trait.label_with_exp_info(
&mut err,
"additional non-auto trait",
"additional use",
);
first_trait.label_with_exp_info(&mut err, "first non-auto trait", "first use");
err.help(format!(
"consider creating a new trait with all of these as supertraits and using that \
trait here instead: `trait NewTrait: {} {{}}`",
regular_traits
.iter()
// FIXME: This should `print_sugared`, but also needs to integrate projection bounds...
.map(|t| t.trait_ref().print_only_trait_path().to_string())
.collect::<Vec<_>>()
.join(" + "),
));
err.note(
"auto-traits like `Send` and `Sync` are traits that have special properties; \
for more information on them, visit \
<https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>",
);
self.set_tainted_by_errors(err.emit());
}

if regular_traits.is_empty() && auto_traits.is_empty() {
let trait_alias_span = trait_bounds
.iter()
.map(|&(trait_ref, _)| trait_ref.def_id())
.find(|&trait_ref| tcx.is_trait_alias(trait_ref))
.map(|trait_ref| tcx.def_span(trait_ref));
let reported =
tcx.dcx().emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span });
self.set_tainted_by_errors(reported);
return Ty::new_error(tcx, reported);
if let Some(reported) = self.report_trait_object_addition_traits_error(
span,
&trait_bounds,
&auto_traits,
&regular_traits,
) {
return Ty::new_error(tcx, reported);
}
}

// Check that there are no gross object safety violations;
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_trait_selection/src/traits/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,7 @@ pub use self::util::{
check_args_compatible, supertrait_def_ids, supertraits, transitive_bounds,
transitive_bounds_that_define_assoc_item, SupertraitDefIds,
};
pub use self::util::{expand_trait_aliases, TraitAliasExpander};
pub use self::util::{expand_trait_aliases, TraitAliasExpander, TraitAliasExpansionInfo};
pub use self::util::{get_vtable_index_of_object_method, impl_item_is_final, upcast_choices};
pub use self::util::{with_replaced_escaping_bound_vars, BoundVarReplacer, PlaceholderReplacer};

Expand Down

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