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use crate::{EarlyContext, EarlyLintPass, LintContext};
use rustc_ast::{Block, StmtKind};
use rustc_errors::{fluent, Applicability};
use rustc_span::Span;
declare_lint! {
pub REDUNDANT_SEMICOLONS,
Warn,
"detects unnecessary trailing semicolons"
}
declare_lint_pass!(RedundantSemicolons => [REDUNDANT_SEMICOLONS]);
impl EarlyLintPass for RedundantSemicolons {
fn check_block(&mut self, cx: &EarlyContext<'_>, block: &Block) {
let mut seq = None;
for stmt in block.stmts.iter() {
match (&stmt.kind, &mut seq) {
(StmtKind::Empty, None) => seq = Some((stmt.span, false)),
(StmtKind::Empty, Some(seq)) => *seq = (seq.0.to(stmt.span), true),
(_, seq) => maybe_lint_redundant_semis(cx, seq),
}
}
maybe_lint_redundant_semis(cx, &mut seq);
}
}
fn maybe_lint_redundant_semis(cx: &EarlyContext<'_>, seq: &mut Option<(Span, bool)>) {
if let Some((span, multiple)) = seq.take() {
if span == rustc_span::DUMMY_SP {
return;
}
cx.struct_span_lint(REDUNDANT_SEMICOLONS, span, |lint| {
lint.build(fluent::lint::redundant_semicolons)
.set_arg("multiple", multiple)
.span_suggestion(span, fluent::lint::suggestion, "", Applicability::MaybeIncorrect)
.emit();
});
}
}