Incorrect conversion of true bool to signed integer

[AlexRTer]

When casting a true bool to a signed integer of any length in a Daphne script it is cast to -1 instead of 1.

print(as.si8(true));     // -1
print(as.si32(true));    // -1
print(as.si64(true));    // -1

// print(as.ui64(true)); // 1

The IR immediately after parsing still shows:

%1 = "daphne.constant"() {value = true} : () -> i1
%2 = "daphne.cast"(%1) : (i1) -> si8

whereas after simplifications (parsing_simplified) these have been wrongfully folded to just

%2 = "daphne.constant"() {value = -1 : si8} : () -> si8