CPP14 grammar parses a body of if-statement as a 'simpleDeclaration'

[unyaunya]

Hi, I'm working on creating a tool on ANTLR with CPP14Parser.g4 grammar. However, as I mentioned in the title, it parses a body-statement after the condition in an if-statement as a 'simpleDeclaration'.
Here is an example of that.
void func(int a) { if(a == 0) print(a); }
In this simple example, the parser ends up with interpreting print(a); as a simpleDeclaration.
I think it is supposed to be a 'postfixExpression'.
I would like to know whether it is some kind of problem or intentionally being like this?
Could anyone give me some help?

[unyaunya]

I learned some of C++grammar. Now I understand that it is due to its grammar's ambiguity. it is not possible to solve without semantic analysis. I will close this Q&A.