bjoernager/rust
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Add suggestion for iterators in iterators

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This commit is contained in:
Kevin Per 2021-02-09 17:18:28 +00:00
parent fe1bf8e05c
commit a3db47ab6c
6 changed files with 62 additions and 4 deletions
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33
compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
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@ -10,16 +10,18 @@ use rustc_middle::mir::{
FakeReadCause, Local, LocalDecl, LocalInfo, LocalKind, Location, Operand, Place, PlaceRef,
ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind, VarBindingForm,
};
use rustc_middle::ty::{self, suggest_constraining_type_param, Instance, Ty};
use rustc_span::{source_map::DesugaringKind, symbol::sym, Span};
use rustc_middle::ty::{self, suggest_constraining_type_param, Ty, TypeFoldable};
use rustc_span::source_map::DesugaringKind;
use rustc_span::symbol::sym;
use rustc_span::Span;
use crate::dataflow::drop_flag_effects;
use crate::dataflow::indexes::{MoveOutIndex, MovePathIndex};
use crate::util::borrowck_errors;
use crate::borrow_check::{
borrow_set::BorrowData, prefixes::IsPrefixOf, InitializationRequiringAction, MirBorrowckCtxt,
PrefixSet, WriteKind,
borrow_set::BorrowData, diagnostics::Instance, prefixes::IsPrefixOf,
InitializationRequiringAction, MirBorrowckCtxt, PrefixSet, WriteKind,
};
use super::{
@ -1267,6 +1269,29 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
if return_span != borrow_span {
err.span_label(borrow_span, note);
let tcx = self.infcx.tcx;
let ty_params = ty::List::empty();
let return_ty = self.regioncx.universal_regions().unnormalized_output_ty;
let return_ty = tcx.erase_regions(return_ty);
// to avoid panics
if !return_ty.has_infer_types() {
if let Some(iter_trait) = tcx.get_diagnostic_item(sym::Iterator) {
if tcx.type_implements_trait((iter_trait, return_ty, ty_params, self.param_env))
{
if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(return_span) {
err.span_suggestion_hidden(
return_span,
"use `.collect()` to allocate the iterator",
format!("{}{}", snippet, ".collect::<Vec<_>>()"),
Applicability::MaybeIncorrect,
);
}
}
}
}
}
Some(err)