rust/clippy_lints/src/serde.rs

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use rustc::lint::*;
use rustc::hir::*;
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use utils::{span_lint, get_trait_def_id, paths};
/// **What it does:** Checks for mis-uses of the serde API.
///
/// **Why is this bad?** Serde is very finnicky about how its API should be
/// used, but the type system can't be used to enforce it (yet).
///
/// **Known problems:** None.
///
/// **Example:** Implementing `Visitor::visit_string` but not `Visitor::visit_str`.
declare_lint! {
pub SERDE_API_MISUSE,
Warn,
"various things that will negatively affect your serde experience"
}
#[derive(Copy, Clone)]
pub struct Serde;
impl LintPass for Serde {
fn get_lints(&self) -> LintArray {
lint_array!(SERDE_API_MISUSE)
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Serde {
fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
if let ItemImpl(_, _, _, Some(ref trait_ref), _, ref items) = item.node {
let did = trait_ref.path.def.def_id();
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if let Some(visit_did) = get_trait_def_id(cx, &paths::SERDE_DE_VISITOR) {
if did == visit_did {
let mut seen_str = None;
let mut seen_string = None;
for item in items {
match &*item.name.as_str() {
"visit_str" => seen_str = Some(item.span),
"visit_string" => seen_string = Some(item.span),
_ => {},
}
}
if let Some(span) = seen_string {
if seen_str.is_none() {
span_lint(cx,
SERDE_API_MISUSE,
span,
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"you should not implement `visit_string` without also implementing `visit_str`");
}
}
}
}
}
}
}