Inconsistencies with unused void* inside checked scopes

[secure-sw-dev-bot]

This issue was copied from checkedc/checkedc-clang#753

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The following code does not pass the checker due to the presence of void *w in the checked block:

int main(int argc, _Ptr<_Ptr<char>> argv) _Checked{
int x = 3;
int i;
_Ptr<int> p = NULL;
p = &x;
void *w;

for(i = 0; i<10; i++) _Checked{
    *p += i;
}
return *p;
}

However, if the void* is inside a struct then it will pass:

typedef struct {
int count;
void* arr;
} Ex;

int main(int argc, _Ptr<_Ptr<char>> argv) _Checked{
int x = 3;
int i;
_Ptr<int> p = NULL;
p = &x;
Ex e;

for(i = 0; i<10; i++) _Checked{
    *p += i;
}
return *p;
}

If the void* inside the struct is used then it is rejected:

typedef struct {
int count;
void* arr;
} Ex;

int main(int argc, _Ptr<_Ptr<char>> argv) _Checked{
int x = 3;
int i;
_Ptr<int> p = NULL;
p = &x;
Ex e;
e.arr = p;
for(i = 0; i<10; i++) _Checked{
    *p += i;
}
return *p;
}

This also applies to functions with void * passed as parameters, for ex: the following function passes the checker:

int foo(void *w) _Checked{
return NULL;
}