Function lemma_optional_end_spec_parse_congruence 

pub proof fn lemma_optional_end_spec_parse_congruence<Inner1: SpecParser, Inner2: SpecParser<PVal = Inner1::PVal>>(
    inner1: Inner1,
    inner2: Inner2,
)

requires

forall |x: Seq<u8>| #[trigger] inner1.spec_parse(x) == inner2.spec_parse(x),

ensures

forall |x: Seq<u8>| {
    #[trigger] OptionalEnd(inner1).spec_parse(x) == OptionalEnd(inner2).spec_parse(x)
},