I mean in the case of an array type that tracks its length at runtime. Take: typedef struct { uint32_t arr1_len, arr2_len; int* arr1; int

I mean in the case of an array type that tracks its length at runtime. Take: typedef struct { uint32_t arr1_len, arr2_len; int* arr1; int* arr2; } Foo; That's, on a 64-bit system, a 24-byte structure. Were it written as a struct of two array fields, the compiler couldn't choose a layout as efficient while maintaining being able to get a pointer to each field. Never mind that the compiler would likely not be omniscient enough to be able to tell that the structure is never used with arrays exceeding 2^32 elements. Perhaps you mean to keep using regular pointers for non-trivial heap-stored things, but I'd imagine that makes up a pretty significant amount of cases with buffer overflow potential.