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suggest &str.chars() on attempt to &str.iter()

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check if `String` or `&String` or `&str`

Update compiler/rustc_typeck/src/check/method/suggest.rs

Co-authored-by: Esteban Kuber <estebank@users.noreply.github.com>

remove some trailing whitespace
This commit is contained in:
Takayuki Maeda 2021-11-12 01:47:43 +09:00
parent 9dbbbb12c0
commit d562f487c9
3 changed files with 75 additions and 0 deletions
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20
compiler/rustc_typeck/src/check/method/suggest.rs
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@ -478,6 +478,26 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let mut label_span_not_found = || {
if unsatisfied_predicates.is_empty() {
err.span_label(span, format!("{item_kind} not found in `{ty_str}`"));
let is_string_or_ref_str = match actual.kind() {
ty::Ref(_, ty, _) => {
ty.is_str()
|| matches!(
ty.kind(),
ty::Adt(adt, _) if self.tcx.is_diagnostic_item(sym::String, adt.did)
)
}
ty::Adt(adt, _) => self.tcx.is_diagnostic_item(sym::String, adt.did),
_ => false,
};
if is_string_or_ref_str && item_name.name == sym::iter {
err.span_suggestion_verbose(
item_name.span,
"because of the in-memory representation of `&str`, to obtain \
an `Iterator` over each of its codepoint use method `chars`",
String::from("chars"),
Applicability::MachineApplicable,
);
}
if let ty::Adt(adt, _) = rcvr_ty.kind() {
let mut inherent_impls_candidate = self
.tcx