1 use super::utils::get_hint_if_single_char_arg;
2 use clippy_utils::diagnostics::span_lint_and_sugg;
3 use if_chain::if_chain;
4 use rustc_errors::Applicability;
6 use rustc_lint::LateContext;
8 use rustc_span::symbol::Symbol;
10 use super::SINGLE_CHAR_PATTERN;
12 const PATTERN_METHODS: [(&str, usize); 19] = [
20 ("split_terminator", 1),
21 ("rsplit_terminator", 1),
27 ("rmatch_indices", 1),
30 ("trim_start_matches", 1),
31 ("trim_end_matches", 1),
34 /// lint for length-1 `str`s for methods in `PATTERN_METHODS`
35 pub(super) fn check(cx: &LateContext<'_>, _expr: &hir::Expr<'_>, method_name: Symbol, args: &[hir::Expr<'_>]) {
36 for &(method, pos) in &PATTERN_METHODS {
38 if let ty::Ref(_, ty, _) = cx.typeck_results().expr_ty_adjusted(&args[0]).kind();
39 if *ty.kind() == ty::Str;
40 if method_name.as_str() == method && args.len() > pos;
42 let mut applicability = Applicability::MachineApplicable;
43 if let Some(hint) = get_hint_if_single_char_arg(cx, arg, &mut applicability);
49 "single-character string constant used as pattern",
50 "try using a `char` instead",