fn parse_dialect(
cx: &mut AcceptContext<'_, '_>,
dialect: Option<(Symbol, Span)>,
failed: &mut bool,
) -> Option<(MirDialect, Span)>fn parse_dialect(
cx: &mut AcceptContext<'_, '_>,
dialect: Option<(Symbol, Span)>,
failed: &mut bool,
) -> Option<(MirDialect, Span)>