rust/clippy_lints/src/methods/single_char_insert_string.rs
2021-03-11 19:40:00 +09:00

28 lines
1.1 KiB
Rust

use crate::methods::get_hint_if_single_char_arg;
use crate::utils::{snippet_with_applicability, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::SINGLE_CHAR_ADD_STR;
/// lint for length-1 `str`s as argument for `insert_str`
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
let mut applicability = Applicability::MachineApplicable;
if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[2], &mut applicability) {
let base_string_snippet =
snippet_with_applicability(cx, args[0].span.source_callsite(), "_", &mut applicability);
let pos_arg = snippet_with_applicability(cx, args[1].span, "..", &mut applicability);
let sugg = format!("{}.insert({}, {})", base_string_snippet, pos_arg, extension_string);
span_lint_and_sugg(
cx,
SINGLE_CHAR_ADD_STR,
expr.span,
"calling `insert_str()` using a single-character string literal",
"consider using `insert` with a character literal",
sugg,
applicability,
);
}
}