1 use clippy_utils::diagnostics::span_lint_and_help;
2 use clippy_utils::ty::is_type_diagnostic_item;
3 use if_chain::if_chain;
4 use rustc_ast::ast::LitKind;
5 use rustc_hir::{Expr, ExprKind};
6 use rustc_lint::LateContext;
7 use rustc_span::{source_map::Spanned, symbol::sym, Span};
9 use super::CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS;
11 pub(super) fn check<'tcx>(
12 cx: &LateContext<'tcx>,
19 if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
20 if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
21 if cx.tcx.type_of(impl_id).is_str();
22 if let ExprKind::Lit(Spanned { node: LitKind::Str(ext_literal, ..), ..}) = arg.kind;
23 if (2..=6).contains(&ext_literal.as_str().len());
24 let ext_str = ext_literal.as_str();
25 if ext_str.starts_with('.');
26 if ext_str.chars().skip(1).all(|c| c.is_uppercase() || c.is_ascii_digit())
27 || ext_str.chars().skip(1).all(|c| c.is_lowercase() || c.is_ascii_digit());
28 let recv_ty = cx.typeck_results().expr_ty(recv).peel_refs();
29 if recv_ty.is_str() || is_type_diagnostic_item(cx, recv_ty, sym::String);
33 CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
35 "case-sensitive file extension comparison",
37 "consider using a case-insensitive comparison instead",