Safe method wont check dangling pointer?

[lzzll]

Let me show some exmaple on c, and two common memory error detect 
tool.

example 1 (stack overflow):
---
int a = 100;
printf("%p\n", &a);

int *b = &a+1;
printf("%p\n", &b);

*b = 100;
---
valgrind: nothing detected
address sanitizer: ==1996== ERROR: AddressSanitizer: 
stack-buffer-overflow on address 0x7fffc976dbc4

example 2 (cross address)
---
int a = 100;
int b = 200;
printf("%p\n", &a);
printf("%p\n", &b);

int *c = &a+(&b-&a);
printf("%p\n", c);

*c = 100;
---
Of course it can't be detected.

example 3 (heap overflow)
---
int *a = (int*) malloc(sizeof(int));
printf("%p\n", a);

int *b = a + 1;
printf("%p\n", b);

*b = 100;
---
valgrind: Address 0x51f0044 is 0 bytes after a block of size 4 
alloc'd
address sanitizer: AddressSanitizer: heap-buffer-overflow on 
address 0x60040000dff4

It's possible to a certain extent.
Reference:
http://valgrind.org/docs/manual/mc-manual.html#mc-manual.vaddress
http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm

I understand implemented this is hard and it need huge cost.
It still be useful if we only use it to detect memory error and 
trun it off when release.
I'll be glad if I can see it on D after some years.