| use clippy_utils::diagnostics::span_lint_and_then; |
| use clippy_utils::ty::is_type_diagnostic_item; |
| use rustc_ast::LitKind; |
| use rustc_data_structures::packed::Pu128; |
| 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 let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) |
| && let Some(impl_id) = cx.tcx.impl_of_method(method_id) |
| && is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id).instantiate_identity(), sym::Vec) |
| && let ExprKind::Lit(Spanned { |
| node: LitKind::Int(Pu128(0), _), |
| .. |
| }) = count_arg.kind |
| && let ExprKind::Lit(Spanned { |
| node: LitKind::Int(..), .. |
| }) = default_arg.kind |
| { |
| 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, |
| ); |
| }, |
| ); |
| } |
| } |