Yet void f(size_t n, int cond) { if (cond) { n += 1; } int x[n]; ... does resize x depending on the value of cond, so the size can't neces

Yet void f(size_t n, int cond) { if (cond) { n += 1; } int x[n]; ... does resize x depending on the value of cond, so the size can't necessarily be known until the point where the type (int[n] in this case) is named. Also, the compiler has to make sure it keeps around implicit locals to store the variable layouts, so that code like void f(size_t n) { typedef int array[n]; n += 1; array x; ... functions as specified. This kind of pattern is one of the bigger things setting the feature apart from just "syntax sugar for alloca()".