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Add a note about type annotation on closure param

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This commit is contained in:
ThibsG 2021-11-28 09:50:34 +01:00
parent 917fdb11e4
commit a8e7fed172
1 changed files with 10 additions and 8 deletions
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18
clippy_utils/src/sugg.rs
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@ -737,12 +737,14 @@ pub struct DerefClosure {
/// such as explicit deref and borrowing cases.
/// Returns `None` if no such use cases have been triggered in closure body
///
/// note: this only works on single line immutable closures with one exactly one input parameter.
/// note: this only works on single line immutable closures with exactly one input parameter.
pub fn deref_closure_args<'tcx>(cx: &LateContext<'_>, closure: &'tcx hir::Expr<'_>) -> Option<DerefClosure> {
if let hir::ExprKind::Closure(_, fn_decl, body_id, ..) = closure.kind {
let closure_body = cx.tcx.hir().body(body_id);
// is closure arg a double reference (i.e.: `|x: &&i32| ...`)
let closure_arg_is_double_ref = if let TyKind::Rptr(_, MutTy { ty, .. }) = fn_decl.inputs[0].kind {
// is closure arg a type annotated double reference (i.e.: `|x: &&i32| ...`)
// a type annotation is present if param `kind` is different from `TyKind::Infer`
let closure_arg_is_type_annotated_double_ref = if let TyKind::Rptr(_, MutTy { ty, .. }) = fn_decl.inputs[0].kind
{
matches!(ty.kind, TyKind::Rptr(_, MutTy { .. }))
} else {
false
@ -751,7 +753,7 @@ pub fn deref_closure_args<'tcx>(cx: &LateContext<'_>, closure: &'tcx hir::Expr<'
let mut visitor = DerefDelegate {
cx,
closure_span: closure.span,
closure_arg_is_double_ref,
closure_arg_is_type_annotated_double_ref,
next_pos: closure.span.lo(),
suggestion_start: String::new(),
applicability: Applicability::MaybeIncorrect,
@ -780,8 +782,8 @@ struct DerefDelegate<'a, 'tcx> {
cx: &'a LateContext<'tcx>,
/// The span of the input closure to adapt
closure_span: Span,
/// Indicates if the arg of the closure is a double reference
closure_arg_is_double_ref: bool,
/// Indicates if the arg of the closure is a type annotated double reference
closure_arg_is_type_annotated_double_ref: bool,
/// last position of the span to gradually build the suggestion
next_pos: BytePos,
/// starting part of the gradually built suggestion
@ -799,7 +801,7 @@ pub fn finish(&mut self) -> String {
let end_span = Span::new(self.next_pos, self.closure_span.hi(), self.closure_span.ctxt(), None);
let end_snip = snippet_with_applicability(self.cx, end_span, "..", &mut self.applicability);
let sugg = format!("{}{}", self.suggestion_start, end_snip);
if self.closure_arg_is_double_ref {
if self.closure_arg_is_type_annotated_double_ref {
sugg.replacen('&', "", 1)
} else {
sugg
@ -889,7 +891,7 @@ fn borrow(&mut self, cmt: &PlaceWithHirId<'tcx>, _: HirId, _: ty::BorrowKind) {
// and if the item is already a double ref
let ident_sugg = if !call_args.is_empty()
&& !takes_arg_by_double_ref
&& (self.closure_arg_is_double_ref || has_field_or_index_projection)
&& (self.closure_arg_is_type_annotated_double_ref || has_field_or_index_projection)
{
let ident = if has_field_or_index_projection {
ident_str_with_proj