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use crate::astconv::AstConv;
use crate::errors::{ManualImplementation, MissingTypeParams};
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{pluralize, struct_span_err, Applicability, ErrorGuaranteed};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_middle::ty;
use rustc_session::parse::feature_err;
use rustc_span::lev_distance::find_best_match_for_name;
use rustc_span::symbol::{sym, Ident};
use rustc_span::{Span, Symbol, DUMMY_SP};
use std::collections::BTreeSet;
impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
pub(crate) fn complain_about_missing_type_params(
&self,
missing_type_params: Vec<Symbol>,
def_id: DefId,
span: Span,
empty_generic_args: bool,
) {
if missing_type_params.is_empty() {
return;
}
self.tcx().sess.emit_err(MissingTypeParams {
span,
def_span: self.tcx().def_span(def_id),
span_snippet: self.tcx().sess.source_map().span_to_snippet(span).ok(),
missing_type_params,
empty_generic_args,
});
}
pub(crate) fn complain_about_internal_fn_trait(
&self,
span: Span,
trait_def_id: DefId,
trait_segment: &'_ hir::PathSegment<'_>,
is_impl: bool,
) {
if self.tcx().features().unboxed_closures {
return;
}
let trait_def = self.tcx().trait_def(trait_def_id);
if !trait_def.paren_sugar {
if trait_segment.args().parenthesized {
let mut err = feature_err(
&self.tcx().sess.parse_sess,
sym::unboxed_closures,
span,
"parenthetical notation is only stable when used with `Fn`-family traits",
);
err.emit();
}
return;
}
let sess = self.tcx().sess;
if !trait_segment.args().parenthesized {
let mut err = feature_err(
&sess.parse_sess,
sym::unboxed_closures,
span,
"the precise format of `Fn`-family traits' type parameters is subject to change",
);
if !is_impl {
let args = trait_segment
.args
.as_ref()
.and_then(|args| args.args.get(0))
.and_then(|arg| match arg {
hir::GenericArg::Type(ty) => match ty.kind {
hir::TyKind::Tup(t) => t
.iter()
.map(|e| sess.source_map().span_to_snippet(e.span))
.collect::<Result<Vec<_>, _>>()
.map(|a| a.join(", ")),
_ => sess.source_map().span_to_snippet(ty.span),
}
.map(|s| format!("({})", s))
.ok(),
_ => None,
})
.unwrap_or_else(|| "()".to_string());
let ret = trait_segment
.args()
.bindings
.iter()
.find_map(|b| match (b.ident.name == sym::Output, &b.kind) {
(true, hir::TypeBindingKind::Equality { term }) => {
let span = match term {
hir::Term::Ty(ty) => ty.span,
hir::Term::Const(c) => self.tcx().hir().span(c.hir_id),
};
sess.source_map().span_to_snippet(span).ok()
}
_ => None,
})
.unwrap_or_else(|| "()".to_string());
err.span_suggestion(
span,
"use parenthetical notation instead",
format!("{}{} -> {}", trait_segment.ident, args, ret),
Applicability::MaybeIncorrect,
);
}
err.emit();
}
if is_impl {
let trait_name = self.tcx().def_path_str(trait_def_id);
self.tcx().sess.emit_err(ManualImplementation { span, trait_name });
}
}
pub(crate) fn complain_about_assoc_type_not_found<I>(
&self,
all_candidates: impl Fn() -> I,
ty_param_name: &str,
assoc_name: Ident,
span: Span,
) -> ErrorGuaranteed
where
I: Iterator<Item = ty::PolyTraitRef<'tcx>>,
{
let span = if assoc_name.span != DUMMY_SP { assoc_name.span } else { span };
let mut err = struct_span_err!(
self.tcx().sess,
span,
E0220,
"associated type `{}` not found for `{}`",
assoc_name,
ty_param_name
);
let all_candidate_names: Vec<_> = all_candidates()
.flat_map(|r| self.tcx().associated_items(r.def_id()).in_definition_order())
.filter_map(
|item| if item.kind == ty::AssocKind::Type { Some(item.name) } else { None },
)
.collect();
if let (Some(suggested_name), true) = (
find_best_match_for_name(&all_candidate_names, assoc_name.name, None),
assoc_name.span != DUMMY_SP,
) {
err.span_suggestion(
assoc_name.span,
"there is an associated type with a similar name",
suggested_name,
Applicability::MaybeIncorrect,
);
return err.emit();
}
let visible_traits: Vec<_> = self
.tcx()
.all_traits()
.filter(|trait_def_id| {
let viz = self.tcx().visibility(*trait_def_id);
if let Some(def_id) = self.item_def_id() {
viz.is_accessible_from(def_id, self.tcx())
} else {
viz.is_visible_locally()
}
})
.collect();
let wider_candidate_names: Vec<_> = visible_traits
.iter()
.flat_map(|trait_def_id| {
self.tcx().associated_items(*trait_def_id).in_definition_order()
})
.filter_map(
|item| if item.kind == ty::AssocKind::Type { Some(item.name) } else { None },
)
.collect();
if let (Some(suggested_name), true) = (
find_best_match_for_name(&wider_candidate_names, assoc_name.name, None),
assoc_name.span != DUMMY_SP,
) {
if let [best_trait] = visible_traits
.iter()
.filter(|trait_def_id| {
self.tcx()
.associated_items(*trait_def_id)
.filter_by_name_unhygienic(suggested_name)
.any(|item| item.kind == ty::AssocKind::Type)
})
.collect::<Vec<_>>()[..]
{
err.span_label(
assoc_name.span,
format!(
"there is a similarly named associated type `{suggested_name}` in the trait `{}`",
self.tcx().def_path_str(*best_trait)
),
);
return err.emit();
}
}
err.span_label(span, format!("associated type `{}` not found", assoc_name));
err.emit()
}
pub(crate) fn complain_about_missing_associated_types(
&self,
associated_types: FxHashMap<Span, BTreeSet<DefId>>,
potential_assoc_types: Vec<Span>,
trait_bounds: &[hir::PolyTraitRef<'_>],
) {
if associated_types.values().all(|v| v.is_empty()) {
return;
}
let tcx = self.tcx();
let mut associated_types: FxHashMap<Span, Vec<_>> = associated_types
.into_iter()
.map(|(span, def_ids)| {
(span, def_ids.into_iter().map(|did| tcx.associated_item(did)).collect())
})
.collect();
let mut names = vec![];
let mut trait_bound_spans: Vec<Span> = vec![];
for (span, items) in &associated_types {
if !items.is_empty() {
trait_bound_spans.push(*span);
}
for assoc_item in items {
let trait_def_id = assoc_item.container_id(tcx);
names.push(format!(
"`{}` (from trait `{}`)",
assoc_item.name,
tcx.def_path_str(trait_def_id),
));
}
}
if let ([], [bound]) = (&potential_assoc_types[..], &trait_bounds) {
match bound.trait_ref.path.segments {
[segment] if segment.args.is_none() => {
trait_bound_spans = vec![segment.ident.span];
associated_types = associated_types
.into_iter()
.map(|(_, items)| (segment.ident.span, items))
.collect();
}
_ => {}
}
}
names.sort();
trait_bound_spans.sort();
let mut err = struct_span_err!(
tcx.sess,
trait_bound_spans,
E0191,
"the value of the associated type{} {} must be specified",
pluralize!(names.len()),
names.join(", "),
);
let mut suggestions = vec![];
let mut types_count = 0;
let mut where_constraints = vec![];
let mut already_has_generics_args_suggestion = false;
for (span, assoc_items) in &associated_types {
let mut names: FxHashMap<_, usize> = FxHashMap::default();
for item in assoc_items {
types_count += 1;
*names.entry(item.name).or_insert(0) += 1;
}
let mut dupes = false;
for item in assoc_items {
let prefix = if names[&item.name] > 1 {
let trait_def_id = item.container_id(tcx);
dupes = true;
format!("{}::", tcx.def_path_str(trait_def_id))
} else {
String::new()
};
if let Some(sp) = tcx.hir().span_if_local(item.def_id) {
err.span_label(sp, format!("`{}{}` defined here", prefix, item.name));
}
}
if potential_assoc_types.len() == assoc_items.len() {
already_has_generics_args_suggestion = true;
} else if let (Ok(snippet), false) =
(tcx.sess.source_map().span_to_snippet(*span), dupes)
{
let types: Vec<_> =
assoc_items.iter().map(|item| format!("{} = Type", item.name)).collect();
let code = if snippet.ends_with('>') {
format!("{}, {}>", &snippet[..snippet.len() - 1], types.join(", "))
} else {
format!("{}<{}>", snippet, types.join(", "))
};
suggestions.push((*span, code));
} else if dupes {
where_constraints.push(*span);
}
}
let where_msg = "consider introducing a new type parameter, adding `where` constraints \
using the fully-qualified path to the associated types";
if !where_constraints.is_empty() && suggestions.is_empty() {
err.help(where_msg);
}
if suggestions.len() != 1 || already_has_generics_args_suggestion {
for (span, assoc_items) in &associated_types {
let mut names: FxHashMap<_, usize> = FxHashMap::default();
for item in assoc_items {
types_count += 1;
*names.entry(item.name).or_insert(0) += 1;
}
let mut label = vec![];
for item in assoc_items {
let postfix = if names[&item.name] > 1 {
let trait_def_id = item.container_id(tcx);
format!(" (from trait `{}`)", tcx.def_path_str(trait_def_id))
} else {
String::new()
};
label.push(format!("`{}`{}", item.name, postfix));
}
if !label.is_empty() {
err.span_label(
*span,
format!(
"associated type{} {} must be specified",
pluralize!(label.len()),
label.join(", "),
),
);
}
}
}
if !suggestions.is_empty() {
err.multipart_suggestion(
&format!("specify the associated type{}", pluralize!(types_count)),
suggestions,
Applicability::HasPlaceholders,
);
if !where_constraints.is_empty() {
err.span_help(where_constraints, where_msg);
}
}
err.emit();
}
}