Fix null initialization (#252)

Author: lucic71

cpp2rust/converter/models/converter_refcount.cpp

@@ -1315,6 +1315,7 @@ bool ConverterRefCount::VisitExplicitCastExpr(clang::ExplicitCastExpr *expr) {
     return false;
   }
   if (expr->getCastKind() == clang::CK_NullToPointer) {
+    PushConversionKind push(*this, ConversionKind::Unboxed);
     StrCat(GetDefaultAsString(expr->getType()));
     computed_expr_type_ = ComputedExprType::FreshPointer;
     return false;

tests/unit/out/refcount/ptr_cast_init.rs

@@ -74,5 +74,30 @@ fn main_0() -> i32 {
     let hp: Value<Ptr<header>> = Rc::new(RefCell::new((h.as_pointer())));
     let v: Value<Ptr<view>> = Rc::new(RefCell::new((*hp.borrow()).reinterpret_cast::<view>()));
     assert!(((((*(*(*v.borrow()).upgrade().deref()).tag.borrow()) == 7) as i32) != 0));
+    let data: Value<Box<[u8]>> = Rc::new(RefCell::new(Box::from(*b"hi\0")));
+    let vp: Value<AnyPtr> = Rc::new(RefCell::new(
+        ((data.as_pointer() as Ptr<u8>) as Ptr<u8>).to_any(),
+    ));
+    let n: Value<i32> = Rc::new(RefCell::new(2));
+    let sel: Value<Ptr<u8>> = Rc::new(RefCell::new(
+        if ((((*n.borrow()) < 100) as i32) != 0) {
+            (*vp.borrow()).clone()
+        } else {
+            (AnyPtr::default())
+        }
+        .reinterpret_cast::<u8>(),
+    ));
+    assert!((((!((*sel.borrow()).is_null())) as i32) != 0));
+    assert!(
+        ((((((*sel.borrow()).offset((0) as isize).read()) as i32) == ('h' as i32)) as i32) != 0)
+    );
+    (*n.borrow_mut()) = 200;
+    (*sel.borrow_mut()) = if ((((*n.borrow()) < 100) as i32) != 0) {
+        (*vp.borrow()).clone()
+    } else {
+        (AnyPtr::default())
+    }
+    .reinterpret_cast::<u8>();
+    assert!(((((*sel.borrow()).is_null()) as i32) != 0));
     return 0;
 }

tests/unit/out/unsafe/ptr_cast_init.rs

@@ -32,5 +32,23 @@ unsafe fn main_0() -> i32 {
     let mut hp: *mut header = (&mut h as *mut header);
     let mut v: *mut view = (hp as *mut view);
     assert!((((((*v).tag) == (7)) as i32) != 0));
+    let mut data: [libc::c_char; 3] = std::mem::transmute(*b"hi\0");
+    let mut vp: *mut ::libc::c_void =
+        (data.as_mut_ptr() as *mut libc::c_char as *mut ::libc::c_void);
+    let mut n: i32 = 2;
+    let mut sel: *mut libc::c_char = (if ((((n) < (100)) as i32) != 0) {
+        vp
+    } else {
+        (0 as *mut ::libc::c_void)
+    } as *mut libc::c_char);
+    assert!((((!((sel).is_null())) as i32) != 0));
+    assert!((((((*sel.offset((0) as isize)) as i32) == ('h' as i32)) as i32) != 0));
+    n = 200;
+    sel = (if ((((n) < (100)) as i32) != 0) {
+        vp
+    } else {
+        (0 as *mut ::libc::c_void)
+    } as *mut libc::c_char);
+    assert!(((((sel).is_null()) as i32) != 0));
     return 0;
 }

tests/unit/ptr_cast_init.c

@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <stddef.h>
 
 struct header {
   int tag;
@@ -20,5 +21,15 @@ int main(void) {
   struct header *hp = &h;
   struct view *v = (struct view *)hp;
   assert(v->tag == 7);
+
+  char data[] = "hi";
+  void *vp = data;
+  int n = 2;
+  char *sel = (n < 100) ? vp : NULL;
+  assert(sel != 0);
+  assert(sel[0] == 'h');
+  n = 200;
+  sel = (n < 100) ? vp : NULL;
+  assert(sel == 0);
   return 0;
 }