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use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::source::snippet_opt;
use clippy_utils::source::{indent_of, reindent_multiline};
use clippy_utils::ty::is_type_lang_item;
use if_chain::if_chain;
use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind, LangItem};
use rustc_lint::LateContext;
use rustc_span::{source_map::Spanned, Span};
use super::CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
call_span: Span,
recv: &'tcx Expr<'_>,
arg: &'tcx Expr<'_>,
) {
if let ExprKind::MethodCall(path_segment, ..) = recv.kind {
if matches!(
path_segment.ident.name.as_str(),
"to_lowercase" | "to_uppercase" | "to_ascii_lowercase" | "to_ascii_uppercase"
) {
return;
}
}
if_chain! {
if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
if cx.tcx.type_of(impl_id).subst_identity().is_str();
if let ExprKind::Lit(Spanned { node: LitKind::Str(ext_literal, ..), ..}) = arg.kind;
if (2..=6).contains(&ext_literal.as_str().len());
let ext_str = ext_literal.as_str();
if ext_str.starts_with('.');
if ext_str.chars().skip(1).all(|c| c.is_uppercase() || c.is_ascii_digit())
|| ext_str.chars().skip(1).all(|c| c.is_lowercase() || c.is_ascii_digit());
let recv_ty = cx.typeck_results().expr_ty(recv).peel_refs();
if recv_ty.is_str() || is_type_lang_item(cx, recv_ty, LangItem::String);
then {
span_lint_and_then(
cx,
CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
recv.span.to(call_span),
"case-sensitive file extension comparison",
|diag| {
diag.help("consider using a case-insensitive comparison instead");
if let Some(mut recv_source) = snippet_opt(cx, recv.span) {
if !cx.typeck_results().expr_ty(recv).is_ref() {
recv_source = format!("&{recv_source}");
}
let suggestion_source = reindent_multiline(
format!(
"std::path::Path::new({})
.extension()
.map_or(false, |ext| ext.eq_ignore_ascii_case(\"{}\"))",
recv_source, ext_str.strip_prefix('.').unwrap()).into(),
true,
Some(indent_of(cx, call_span).unwrap_or(0) + 4)
);
diag.span_suggestion(
recv.span.to(call_span),
"use std::path::Path",
suggestion_source,
Applicability::MaybeIncorrect,
);
}
}
);
}
}
}
|
