1 use crate::utils::paths::STRING;
2 use crate::utils::{match_def_path, span_lint_and_help};
3 use if_chain::if_chain;
4 use rustc_ast::ast::LitKind;
5 use rustc_hir::{Expr, ExprKind, PathSegment};
6 use rustc_lint::{LateContext, LateLintPass};
8 use rustc_session::{declare_lint_pass, declare_tool_lint};
9 use rustc_span::{source_map::Spanned, Span};
11 declare_clippy_lint! {
13 /// Checks for calls to `ends_with` with possible file extensions
14 /// and suggests to use a case-insensitive approach instead.
16 /// **Why is this bad?**
17 /// `ends_with` is case-sensitive and may not detect files with a valid extension.
19 /// **Known problems:** None.
24 /// fn is_rust_file(filename: &str) -> bool {
25 /// filename.ends_with(".rs")
30 /// fn is_rust_file(filename: &str) -> bool {
31 /// filename.rsplit('.').next().map(|ext| ext.eq_ignore_ascii_case("rs")) == Some(true)
34 pub CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
36 "Checks for calls to ends_with with case-sensitive file extensions"
39 declare_lint_pass!(CaseSensitiveFileExtensionComparisons => [CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS]);
41 fn check_case_sensitive_file_extension_comparison(ctx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Span> {
43 if let ExprKind::MethodCall(PathSegment { ident, .. }, _, [obj, extension, ..], span) = expr.kind;
44 if ident.as_str() == "ends_with";
45 if let ExprKind::Lit(Spanned { node: LitKind::Str(ext_literal, ..), ..}) = extension.kind;
46 if (2..=6).contains(&ext_literal.as_str().len());
47 if ext_literal.as_str().starts_with('.');
48 if ext_literal.as_str().chars().skip(1).all(|c| c.is_uppercase() || c.is_digit(10))
49 || ext_literal.as_str().chars().skip(1).all(|c| c.is_lowercase() || c.is_digit(10));
51 let mut ty = ctx.typeck_results().expr_ty(obj);
52 ty = match ty.kind() {
53 ty::Ref(_, ty, ..) => ty,
61 ty::Adt(&ty::AdtDef { did, .. }, _) => {
62 if match_def_path(ctx, did, &STRING) {
73 impl LateLintPass<'tcx> for CaseSensitiveFileExtensionComparisons {
74 fn check_expr(&mut self, ctx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
75 if let Some(span) = check_case_sensitive_file_extension_comparison(ctx, expr) {
78 CASE_SENSITIVE_FILE_EXTENSION_COMPARISONS,
80 "case-sensitive file extension comparison",
82 "consider using a case-insensitive comparison instead",