[internalAstError] when assigning a compound literal with designators and array access

[Bento Borges Schirmer]

Hello

Cppcheck (version 2.3) have been serving me really well, but yesterday I came across to an internalAstError.
The following C code assigns to a the fifth element on an array initialized using a compound literal and designators to initialize its elements.

int main(void)
{
        int a = (int[]){[4] = 1}[4];
        return (a);
}

Although it compiles and runs fine using GCC, Clang and TCC without warnings (-Wpedantic -Wall -Wextra), running the bellow gives the following output:

$ cppcheck --debug assignment-of-designated-initialized-compound-literal.c
Checking assignment-of-designated-initialized-compound-literal.c ...
assignment-of-designated-initialized-compound-literal.c:3:8: error: Syntax Error: AST broken, binary operator '=' doesn't have two operands. [internalAstError]
 int a = (int[]){[4] = 1}[4];
       ^

However, this seems to run fine:

int main(void)
{
        int *a = (int[]){[4] = 1};

        return (a[4]);
}

Or this, but this one raises [unusedFunction] when run with --enable=all:

static int function(int a)
{
        return (a);
}

int main(void)
{
        int a = function((int[]){[4] = 1}[4]);

        return (a);
}

I saw on Trac this issue, but I dunno if it is related: https://trac.cppcheck.net/ticket/9513

Thanks in advance!

[CHR]

Adding parentheses around the cast also avoids the warnings:

int main1()
{
        int a = ((int[]){[4] = 1})[4];
        return a;
}

int f(int a)
{
        return a;
}

int main2()
{
        int a = f( ((int[]){[4] = 1})[4] );

        return a;
}

Looking at the value flow (as far as I understand it), it seems that cppcheck doesn't quite parse this expression correctly though.
(Added missing parentheses.)

[CHR]

I have created a ticket: https://trac.cppcheck.net/ticket/10177