1 use crate::utils::{get_trait_def_id, paths, span_lint};
2 use rustc::declare_lint_pass;
4 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
5 use rustc_session::declare_tool_lint;
8 /// **What it does:** Checks for mis-uses of the serde API.
10 /// **Why is this bad?** Serde is very finnicky about how its API should be
11 /// used, but the type system can't be used to enforce it (yet?).
13 /// **Known problems:** None.
15 /// **Example:** Implementing `Visitor::visit_string` but not
16 /// `Visitor::visit_str`.
19 "various things that will negatively affect your serde experience"
22 declare_lint_pass!(SerdeAPI => [SERDE_API_MISUSE]);
24 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for SerdeAPI {
25 fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
26 if let ItemKind::Impl(_, _, _, _, Some(ref trait_ref), _, ref items) = item.kind {
27 let did = trait_ref.path.res.def_id();
28 if let Some(visit_did) = get_trait_def_id(cx, &paths::SERDE_DE_VISITOR) {
30 let mut seen_str = None;
31 let mut seen_string = None;
33 match &*item.ident.as_str() {
34 "visit_str" => seen_str = Some(item.span),
35 "visit_string" => seen_string = Some(item.span),
39 if let Some(span) = seen_string {
40 if seen_str.is_none() {
45 "you should not implement `visit_string` without also implementing `visit_str`",