1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::ty::is_type_diagnostic_item;
use if_chain::if_chain;
use rustc_ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind};
use rustc_lint::LateContext;
use rustc_span::source_map::Spanned;
use rustc_span::{sym, Span};
use super::VEC_RESIZE_TO_ZERO;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
count_arg: &'tcx Expr<'_>,
default_arg: &'tcx Expr<'_>,
name_span: Span,
) {
if_chain! {
if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Vec);
if let ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = count_arg.kind;
if let ExprKind::Lit(Spanned { node: LitKind::Int(..), .. }) = default_arg.kind;
then {
let method_call_span = expr.span.with_lo(name_span.lo());
span_lint_and_then(
cx,
VEC_RESIZE_TO_ZERO,
expr.span,
"emptying a vector with `resize`",
|db| {
db.help("the arguments may be inverted...");
db.span_suggestion(
method_call_span,
"...or you can empty the vector with",
"clear()".to_string(),
Applicability::MaybeIncorrect,
);
},
);
}
}
}
|
