The revently added clang directive cause a new warning for Visual Studio build. Need to include the new code with a directive checking for visual studio
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As documented previousTokenOnChannel, should "return -1 if there are no tokens on channel between i and 0." but the C++ version of the runtime returns 0 not -1 as can be seen below:
```
while (true) {
Token *token = _tokens[i].get();
if (token->getType() == Token::EOF || token->getChannel() == channel) {
return i;
}
if (i == 0)
break;
i--;
}
```
Looking at the Java implementation, it would seem the C++ code should instead be:
```
while (true) {
Token *token = _tokens[i].get();
if (token->getType() == Token::EOF || token->getChannel() == channel) {
return i;
}
if (i == 0)
return -1;
i--;
}
```
This bug causes getHiddenTokensToLeft() to miss hidden tokens that come before the first non-hidden token. There would also be a potential bug in CommonTokenStream::LB as the "< 0" case would never happen.
In the orignal PredictionContext::mergeArrays there was a bug on Line 281 where the logic differs from java: It currently is:
bool both$ = payload == EMPTY_RETURN_STATE && a_parent && b_parent;
and should instead match java as:
bool both$ = payload == EMPTY_RETURN_STATE && !a_parent && !b_parent;
olowo726
Terence Parr
Thomas
Ralu
You Kaichao
Eric Vergnaud
WalterCouto
ralf
nxtstep
Ewan Mellor