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use clippy_utils::SpanlessEq;
use clippy_utils::diagnostics::span_lint;
use clippy_utils::ty::is_type_lang_item;
use rustc_ast::LitKind;
use rustc_hir::{ExprKind, LangItem};
use rustc_lint::LateContext;
use super::NO_EFFECT_REPLACE;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx rustc_hir::Expr<'_>,
arg1: &'tcx rustc_hir::Expr<'_>,
arg2: &'tcx rustc_hir::Expr<'_>,
) {
let ty = cx.typeck_results().expr_ty(expr).peel_refs();
if !(ty.is_str() || is_type_lang_item(cx, ty, LangItem::String)) {
return;
}
if let ExprKind::Lit(spanned) = &arg1.kind
&& let Some(param1) = lit_string_value(&spanned.node)
&& let ExprKind::Lit(spanned) = &arg2.kind
&& let LitKind::Str(param2, _) = &spanned.node
&& param1 == param2.as_str()
{
span_lint(cx, NO_EFFECT_REPLACE, expr.span, "replacing text with itself");
return;
}
if SpanlessEq::new(cx).eq_expr(arg1, arg2) {
span_lint(cx, NO_EFFECT_REPLACE, expr.span, "replacing text with itself");
}
}
fn lit_string_value(node: &LitKind) -> Option<String> {
match node {
LitKind::Char(value) => Some(value.to_string()),
LitKind::Str(value, _) => Some(value.as_str().to_owned()),
_ => None,
}
}
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