src/tools/clippy/clippy_lints/src/methods/single_char_insert_string.rs

   1 use super::utils::get_hint_if_single_char_arg;
   2 use clippy_utils::diagnostics::span_lint_and_sugg;
   3 use clippy_utils::source::snippet_with_applicability;
   4 use rustc_errors::Applicability;
   5 use rustc_hir as hir;
   6 use rustc_lint::LateContext;
   7
   8 use super::SINGLE_CHAR_ADD_STR;
   9
  10 /// lint for length-1 `str`s as argument for `insert_str`
  11 pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, receiver: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
  12     let mut applicability = Applicability::MachineApplicable;
  13     if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[1], &mut applicability) {
  14         let base_string_snippet =
  15             snippet_with_applicability(cx, receiver.span.source_callsite(), "_", &mut applicability);
  16         let pos_arg = snippet_with_applicability(cx, args[0].span, "..", &mut applicability);
  17         let sugg = format!("{}.insert({}, {})", base_string_snippet, pos_arg, extension_string);
  18         span_lint_and_sugg(
  19             cx,
  20             SINGLE_CHAR_ADD_STR,
  21             expr.span,
  22             "calling `insert_str()` using a single-character string literal",
  23             "consider using `insert` with a character literal",
  24             sugg,
  25             applicability,
  26         );
  27     }
  28 }