/// returns a span and `ArgKind` information that describes the
/// arguments it expects. This can be supplied to
/// `report_arg_count_mismatch`.
- fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Vec<ArgKind>)>;
+ fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Option<Span>, Vec<ArgKind>)>;
/// Reports an error when the number of arguments needed by a
/// trait match doesn't match the number that the expression
expected_args: Vec<ArgKind>,
found_args: Vec<ArgKind>,
is_closure: bool,
+ closure_pipe_span: Option<Span>,
) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
/// Checks if the type implements one of `Fn`, `FnMut`, or `FnOnce`
/// returns a span and `ArgKind` information that describes the
/// arguments it expects. This can be supplied to
/// `report_arg_count_mismatch`.
- fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Vec<ArgKind>)> {
+ fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Option<Span>, Vec<ArgKind>)> {
let sm = self.tcx.sess.source_map();
let hir = self.tcx.hir();
Some(match node {
Node::Expr(&hir::Expr {
- kind: hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }),
+ kind: hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, fn_arg_span, .. }),
..
}) => (
fn_decl_span,
+ fn_arg_span,
hir.body(body)
.params
.iter()
kind: hir::TraitItemKind::Fn(ref sig, _), ..
}) => (
sig.span,
+ None,
sig.decl
.inputs
.iter()
),
Node::Ctor(ref variant_data) => {
let span = variant_data.ctor_hir_id().map_or(DUMMY_SP, |id| hir.span(id));
- (span, vec![ArgKind::empty(); variant_data.fields().len()])
+ (span, None, vec![ArgKind::empty(); variant_data.fields().len()])
}
_ => panic!("non-FnLike node found: {:?}", node),
})
expected_args: Vec<ArgKind>,
found_args: Vec<ArgKind>,
is_closure: bool,
+ closure_arg_span: Option<Span>,
) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
let kind = if is_closure { "closure" } else { "function" };
if let Some(found_span) = found_span {
err.span_label(found_span, format!("takes {}", found_str));
- // move |_| { ... }
- // ^^^^^^^^-- def_span
- //
- // move |_| { ... }
- // ^^^^^-- prefix
- let prefix_span = self.tcx.sess.source_map().span_until_non_whitespace(found_span);
- // move |_| { ... }
- // ^^^-- pipe_span
- let pipe_span =
- if let Some(span) = found_span.trim_start(prefix_span) { span } else { found_span };
-
// Suggest to take and ignore the arguments with expected_args_length `_`s if
// found arguments is empty (assume the user just wants to ignore args in this case).
// For example, if `expected_args_length` is 2, suggest `|_, _|`.
if found_args.is_empty() && is_closure {
let underscores = vec!["_"; expected_args.len()].join(", ");
err.span_suggestion_verbose(
- pipe_span,
+ closure_arg_span.unwrap_or(found_span),
&format!(
"consider changing the closure to take and ignore the expected argument{}",
pluralize!(expected_args.len())
obligation.cause.code(),
)
} else {
- let (closure_span, found) = found_did
+ let (closure_span, closure_arg_span, found) = found_did
.and_then(|did| {
let node = self.tcx.hir().get_if_local(did)?;
- let (found_span, found) = self.get_fn_like_arguments(node)?;
- Some((Some(found_span), found))
+ let (found_span, closure_arg_span, found) =
+ self.get_fn_like_arguments(node)?;
+ Some((Some(found_span), closure_arg_span, found))
})
- .unwrap_or((found_span, found));
+ .unwrap_or((found_span, None, found));
self.report_arg_count_mismatch(
span,
expected,
found,
found_trait_ty.is_closure(),
+ closure_arg_span,
)
}
}
}
self.probe(|_| {
- let mut err = error.err;
- let mut values = None;
+ let ocx = ObligationCtxt::new_in_snapshot(self);
// try to find the mismatched types to report the error with.
//
// this can fail if the problem was higher-ranked, in which
// cause I have no idea for a good error message.
let bound_predicate = predicate.kind();
- if let ty::PredicateKind::Clause(ty::Clause::Projection(data)) =
+ let (values, err) = if let ty::PredicateKind::Clause(ty::Clause::Projection(data)) =
bound_predicate.skip_binder()
{
- let mut selcx = SelectionContext::new(self);
let data = self.replace_bound_vars_with_fresh_vars(
obligation.cause.span,
infer::LateBoundRegionConversionTime::HigherRankedType,
bound_predicate.rebind(data),
);
- let mut obligations = vec![];
- // FIXME(normalization): Change this to use `At::normalize`
- let normalized_ty = super::normalize_projection_type(
- &mut selcx,
+ let normalized_ty = ocx.normalize(
+ &obligation.cause,
obligation.param_env,
- data.projection_ty,
- obligation.cause.clone(),
- 0,
- &mut obligations,
+ self.tcx
+ .mk_projection(data.projection_ty.item_def_id, data.projection_ty.substs),
);
debug!(?obligation.cause, ?obligation.param_env);
| ObligationCauseCode::ObjectCastObligation(..)
| ObligationCauseCode::OpaqueType
);
- if let Err(new_err) = self.at(&obligation.cause, obligation.param_env).eq_exp(
+ let expected_ty = data.term.ty().unwrap_or_else(|| self.tcx.ty_error());
+
+ // constrain inference variables a bit more to nested obligations from normalize so
+ // we can have more helpful errors.
+ ocx.select_where_possible();
+
+ if let Err(new_err) = ocx.eq_exp(
+ &obligation.cause,
+ obligation.param_env,
is_normalized_ty_expected,
normalized_ty,
- data.term,
+ expected_ty,
) {
- values = Some((data, is_normalized_ty_expected, normalized_ty, data.term));
- err = new_err;
+ (Some((data, is_normalized_ty_expected, normalized_ty, expected_ty)), new_err)
+ } else {
+ (None, error.err)
}
- }
+ } else {
+ (None, error.err)
+ };
let msg = values
.and_then(|(predicate, _, normalized_ty, expected_ty)| {
- self.maybe_detailed_projection_msg(predicate, normalized_ty, expected_ty)
+ self.maybe_detailed_projection_msg(
+ predicate,
+ normalized_ty.into(),
+ expected_ty.into(),
+ )
})
.unwrap_or_else(|| format!("type mismatch resolving `{}`", predicate));
let mut diag = struct_span_err!(self.tcx.sess, obligation.cause.span, E0271, "{msg}");
&mut diag,
&obligation.cause,
secondary_span,
- values.map(|(_, is_normalized_ty_expected, normalized_ty, term)| {
+ values.map(|(_, is_normalized_ty_expected, normalized_ty, expected_ty)| {
infer::ValuePairs::Terms(ExpectedFound::new(
is_normalized_ty_expected,
- normalized_ty,
- term,
+ normalized_ty.into(),
+ expected_ty.into(),
))
}),
err,
&self,
trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> Vec<ImplCandidate<'tcx>> {
- self.tcx
+ let mut candidates: Vec<_> = self
+ .tcx
.all_impls(trait_pred.def_id())
.filter_map(|def_id| {
if self.tcx.impl_polarity(def_id) == ty::ImplPolarity::Negative
self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false)
.map(|similarity| ImplCandidate { trait_ref: imp, similarity })
})
- .collect()
+ .collect();
+ if candidates.iter().any(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. })) {
+ // If any of the candidates is a perfect match, we don't want to show all of them.
+ // This is particularly relevant for the case of numeric types (as they all have the
+ // same cathegory).
+ candidates.retain(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. }));
+ }
+ candidates
}
fn report_similar_impl_candidates(