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Make comparison_to_empty work on if let/let chains

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refactor it
This commit is contained in:
Catherine 2023-06-26 00:20:31 -05:00 • committed by Catherine Flores
parent 58df1e64cb
commit da93ee86e5
5 changed files with 176 additions and 10 deletions
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30
clippy_lints/src/len_zero.rs
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@ -7,11 +7,10 @@ use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::def::Res;
use rustc_hir::def_id::{DefId, DefIdSet};
use rustc_hir::lang_items::LangItem;
use rustc_hir::{
AssocItemKind, BinOpKind, Expr, ExprKind, FnRetTy, GenericArg, GenericBound, ImplItem, ImplItemKind,
ImplicitSelfKind, Item, ItemKind, Mutability, Node, PathSegment, PrimTy, QPath, TraitItemRef, TyKind,
TypeBindingKind,
ImplicitSelfKind, Item, ItemKind, LangItem, Mutability, Node, PatKind, PathSegment, PrimTy, QPath, TraitItemRef,
TyKind, TypeBindingKind,
};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty::{self, AssocKind, FnSig, Ty};
@ -168,6 +167,31 @@ impl<'tcx> LateLintPass<'tcx> for LenZero {
return;
}
if let ExprKind::Let(lt) = expr.kind
&& has_is_empty(cx, lt.init)
&& match lt.pat.kind {
PatKind::Slice([], _, []) => true,
PatKind::Lit(lit) if is_empty_string(lit) => true,
_ => false,
}
{
let mut applicability = Applicability::MachineApplicable;
let lit1 = peel_ref_operators(cx, lt.init);
let lit_str =
Sugg::hir_with_context(cx, lit1, lt.span.ctxt(), "_", &mut applicability).maybe_par();
span_lint_and_sugg(
cx,
COMPARISON_TO_EMPTY,
lt.span,
"comparison to empty slice using `if let`",
"using `is_empty` is clearer and more explicit",
format!("{lit_str}.is_empty()"),
applicability,
);
}
if let ExprKind::Binary(Spanned { node: cmp, .. }, left, right) = expr.kind {
// expr.span might contains parenthesis, see issue #10529
let actual_span = left.span.with_hi(right.span.hi());