use std::collections::BTreeMap;
use std::fmt::Debug;
-use std::iter;
use std::mem;
use smallvec::SmallVec;
use syntax::attr;
.collect::<P<[hir::Field]>>();
let is_unit = fields.is_empty();
- let struct_path = iter::once("ops")
- .chain(iter::once(path))
- .collect::<Vec<_>>();
+ let struct_path = ["ops", path];
let struct_path = self.std_path(e.span, &struct_path, None, is_unit);
let struct_path = hir::QPath::Resolved(None, P(struct_path));
let wf_conditions = iter::once(ty::Binder::dummy(trait_pred.lower()))
.chain(
where_clauses
- .iter()
- .cloned()
+ .into_iter()
.map(|wc| wc.map_bound(|goal| goal.into_well_formed_goal()))
);
// `WC`
let where_clauses = tcx.predicates_of(def_id).predicates
.into_iter()
- .map(|(wc, _)| wc.lower())
- .collect::<Vec<_>>();
+ .map(|(wc, _)| wc.lower());
// `Implemented(A0: Trait<A1..An>) :- WC`
let clause = ProgramClause {
goal: trait_pred,
hypotheses: tcx.mk_goals(
where_clauses
- .into_iter()
.map(|wc| tcx.mk_goal(GoalKind::from_poly_domain_goal(wc, tcx))),
),
};
// field is of the found type, suggest such variants. See Issue
// #42764.
if let ty::Adt(expected_adt, substs) = expected.sty {
- let compatible_variants = expected_adt.variants
+ let mut compatible_variants = expected_adt.variants
.iter()
.filter(|variant| variant.fields.len() == 1)
.filter_map(|variant| {
} else {
None
}
- }).collect::<Vec<_>>();
+ }).peekable();
- if !compatible_variants.is_empty() {
+ if compatible_variants.peek().is_some() {
let expr_text = print::to_string(print::NO_ANN, |s| s.print_expr(expr));
- let suggestions = compatible_variants.iter()
- .map(|v| format!("{}({})", v, expr_text)).collect::<Vec<_>>();
+ let suggestions = compatible_variants.map(|v|
+ format!("{}({})", v, expr_text)).collect::<Vec<_>>();
err.span_suggestions_with_applicability(
expr.span,
"try using a variant of the expected type",