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use crate::rule_prelude::*;
use ast::SwitchStmt;
declare_lint! {
#[derive(Default)]
NoDuplicateCases,
errors,
"no-duplicate-cases"
}
#[typetag::serde]
impl CstRule for NoDuplicateCases {
fn check_node(&self, node: &SyntaxNode, ctx: &mut RuleCtx) -> Option<()> {
if let Some(switch) = node.try_to::<SwitchStmt>() {
let mut seen: Vec<SyntaxNode> = vec![];
for case in switch.cases().filter_map(|case| case.into_case()) {
if let Some(expr) = case.test() {
if let Some(old) = seen.iter().find(|clause| clause.lexical_eq(expr.syntax())) {
let err = ctx
.err(
self.name(),
format!("duplicate switch statement test `{}`", old.trimmed_text()),
)
.secondary(
old,
format!("`{}` is first tested for here", old.trimmed_text()),
)
.primary(
expr.syntax(),
format!(
"`{}` is then tested for again here",
expr.syntax().trimmed_text()
),
);
ctx.add_err(err)
} else {
seen.push(expr.syntax().clone());
}
}
}
}
None
}
}
rule_tests! {
NoDuplicateCases::default(),
err: {
"
switch (foo) {
case foo. bar:
break;
case foo.bar:
break;
}
",
"
switch foo {
case 5:
break;
case 6:
break;
case 5:
break;
}
"
},
ok: {}
}