Rollup merge of #88578 - notriddle:notriddle/suggest-add-reference-to-for-loop-iter, r=nagisa

fix(rustc): suggest `items` be borrowed in `for i in items[x..]`

Fixes #87994
This commit is contained in:
Manish Goregaokar 2021-09-10 08:23:18 -07:00 committed by GitHub
commit 257f5adf0e
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4 changed files with 105 additions and 6 deletions

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@ -23,7 +23,7 @@ use rustc_middle::ty::{
use rustc_middle::ty::{TypeAndMut, TypeckResults};
use rustc_span::def_id::LOCAL_CRATE;
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{BytePos, MultiSpan, Span, DUMMY_SP};
use rustc_span::{BytePos, DesugaringKind, ExpnKind, ForLoopLoc, MultiSpan, Span, DUMMY_SP};
use rustc_target::spec::abi;
use std::fmt;
@ -680,7 +680,13 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
points_at_arg: bool,
has_custom_message: bool,
) -> bool {
if !points_at_arg {
let span = obligation.cause.span;
let points_at_for_iter = matches!(
span.ctxt().outer_expn_data().kind,
ExpnKind::Desugaring(DesugaringKind::ForLoop(ForLoopLoc::IntoIter))
);
if !points_at_arg && !points_at_for_iter {
return false;
}
@ -695,7 +701,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
never_suggest_borrow.push(self.tcx.get_diagnostic_item(sym::send_trait).unwrap());
let span = obligation.cause.span;
let param_env = obligation.param_env;
let trait_ref = trait_ref.skip_binder();
@ -754,7 +759,11 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
);
// This if is to prevent a special edge-case
if !span.from_expansion() {
if matches!(
span.ctxt().outer_expn_data().kind,
ExpnKind::Root
| ExpnKind::Desugaring(DesugaringKind::ForLoop(ForLoopLoc::IntoIter))
) {
// We don't want a borrowing suggestion on the fields in structs,
// ```
// struct Foo {