Fix rvalue usage of vector<bool>::reference (#576)

`vector<bool>::reference` is not a real reference type, it's a proxy.
Handle that using ExprMapsValueToPointer which checks values, the vector
bool reference, translated as pointers.

Also use __a0 = a0 in the vector rules because I++ runs 2 times
otherwise.

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -1840,11 +1840,16 @@ bool Converter::ConvertSpecialCall(clang::CallExpr *expr) {
   return false;
 }
 
+bool Converter::ExprMapsValueToPointer(const clang::CallExpr *expr) const {
+  return Mapper::Contains(ctx_, expr) && !expr->getType()->isPointerType() &&
+         RuleRegistry::MapsToPointer(ctx_, expr->getType());
+}
+
 void Converter::EmitCallResult(clang::CallExpr *expr, std::string str,
                                const TempMaterializationCtx *temps) {
   bool deref = (GetReturnTypeOfFunction(expr)->isReferenceType() ||
                 (temps && IsReferenceType(expr))) &&
-               !isAddrOf() && !isVoid();
+               !isAddrOf() && !isVoid() && !ExprMapsValueToPointer(expr);
   // The dereference is in the block of the temporaries, so they are still
   // alive, as is the read of a field of the result.
   if (deref && !(temps && Mapper::IsRefExpr(ctx_, expr))) {

cpp2rust/converter/converter.h

@@ -899,6 +899,8 @@ class Converter : public clang::RecursiveASTVisitor<Converter> {
 
   virtual bool IsReferenceType(const clang::Expr *expr) const;
 
+  bool ExprMapsValueToPointer(const clang::CallExpr *expr) const;
+
   virtual bool RecordDerivesDefault(const clang::RecordDecl *decl);
 
   virtual bool TypeDerivesDefault(clang::QualType qual_type);

cpp2rust/converter/models/converter_refcount.cpp

@@ -1237,7 +1237,7 @@ void ConverterRefCount::EmitCallResult(clang::CallExpr *expr, std::string str,
   };
   auto ty = GetReturnTypeOfFunction(expr);
   if (auto *ref = ty->getAs<clang::ReferenceType>();
-      ref && !isAddrOf() && !isVoid()) {
+      ref && !isAddrOf() && !isVoid() && !ExprMapsValueToPointer(expr)) {
     if (isLValue()) {
       pending_deref_.set(wrap(std::move(str)), /*fresh=*/true);
       return;

rules/vector/tgt_refcount.rs

@@ -160,16 +160,19 @@ fn f118<T1>(a0: Ptr<bool>, a1: usize) -> Ptr<bool> {
 }
 
 fn f119(a0: Ptr<bool>, a1: bool) -> Ptr<bool> {
-    a0.write(a1);
-    a0
+    let __a0 = a0;
+    __a0.write(a1);
+    __a0
 }
 
 fn f120(a0: Ptr<bool>, a1: bool) -> Ptr<bool> {
-    a0.write(a1);
-    a0
+    let __a0 = a0;
+    __a0.write(a1);
+    __a0
 }
 
 fn f121(a0: Ptr<bool>, a1: Ptr<bool>) -> Ptr<bool> {
-    a0.write(a1.read());
-    a0
+    let __a0 = a0;
+    __a0.write(a1.read());
+    __a0
 }

rules/vector/tgt_unsafe.rs

@@ -267,16 +267,19 @@ unsafe fn f118<T1>(a0: &mut Vec<bool>, a1: usize) -> *mut bool {
 }
 
 unsafe fn f119(a0: *mut bool, a1: bool) -> *mut bool {
-    *a0 = a1;
-    a0
+    let __a0 = a0;
+    *__a0 = a1;
+    __a0
 }
 
 unsafe fn f120(a0: *mut bool, a1: bool) -> *mut bool {
-    *a0 = a1;
-    a0
+    let __a0 = a0;
+    *__a0 = a1;
+    __a0
 }
 
 unsafe fn f121(a0: *mut bool, a1: *mut bool) -> *mut bool {
-    *a0 = *a1;
-    a0
+    let __a0 = a0;
+    *__a0 = *a1;
+    __a0
 }

tests/unit/out/refcount/vector_bool_reference.rs

@@ -15,33 +15,33 @@ fn main_0() -> i32 {
     let mut r1: Ptr<bool> = v1.decay().offset(0_usize as isize);
     assert!((v1.decay().offset(0_usize as isize).read()) && (r1.read()));
     {
-        r1.write(false);
-        (r1).clone()
+        let __a0 = (r1).clone();
+        __a0.write(false);
+        __a0
     };
     assert!(!(v1.decay().offset(0_usize as isize).read()));
     let it: Value<RandomAccessIterator<bool>> = Rc::new(RefCell::new(v1.decay().begin()));
     let mut r2: Ptr<bool> = (*it.borrow()).iter_deref();
     {
-        r2.write(true);
-        (r2).clone()
+        let __a0 = (r2).clone();
+        __a0.write(true);
+        __a0
     };
     assert!(v1.decay().offset(0_usize as isize).read());
     {
-        v1.decay().offset(0_usize as isize).write(false);
-        v1.decay().offset(0_usize as isize)
+        let __a0 = v1.decay().offset(0_usize as isize);
+        __a0.write(false);
+        __a0
     };
     assert!(!(v1.decay().offset(0_usize as isize).read()));
     {
         let v: Value<Vec<bool>> = Rc::new(RefCell::new(Vec::from([false, false, false])));
         let mut i: i32 = 0;
-        let mut b: bool = (*{
-            v.decay()
-                .offset((i.postfix_inc() as usize) as isize)
-                .write(true);
-            v.decay().offset((i.postfix_inc() as usize) as isize)
+        let mut b: bool = {
+            let __a0 = v.decay().offset((i.postfix_inc() as usize) as isize);
+            __a0.write(true);
+            __a0
         }
-        .upgrade()
-        .deref())
         .read();
         assert!(b);
     }

tests/unit/out/unsafe/vector_bool_reference.rs

@@ -17,29 +17,33 @@ unsafe fn main_0() -> i32 {
     let mut r1: *mut bool = (&mut (v1)[0_usize as usize] as *mut bool);
     assert!((*(&mut (v1)[0_usize as usize] as *mut bool)) && (*r1));
     {
-        *r1 = false;
-        r1
+        let __a0 = r1;
+        *__a0 = false;
+        __a0
     };
     assert!(!(*(&mut (v1)[0_usize as usize] as *mut bool)));
     let mut it: UnsafeRandomAccessIterator<bool> = v1.begin();
     let mut r2: *mut bool = it.iter_deref();
     {
-        *r2 = true;
-        r2
+        let __a0 = r2;
+        *__a0 = true;
+        __a0
     };
     assert!(*(&mut (v1)[0_usize as usize] as *mut bool));
     {
-        *(&mut (v1)[0_usize as usize] as *mut bool) = false;
-        (&mut (v1)[0_usize as usize] as *mut bool)
+        let __a0 = (&mut (v1)[0_usize as usize] as *mut bool);
+        *__a0 = false;
+        __a0
     };
     assert!(!(*(&mut (v1)[0_usize as usize] as *mut bool)));
     {
         let mut v: Vec<bool> = Vec::from([false, false, false]);
         let mut i: i32 = 0;
-        let mut b: bool = *(*{
-            *(&mut (v)[(i.postfix_inc() as usize) as usize] as *mut bool) = true;
-            (&mut (v)[(i.postfix_inc() as usize) as usize] as *mut bool)
-        });
+        let mut b: bool = *{
+            let __a0 = (&mut (v)[(i.postfix_inc() as usize) as usize] as *mut bool);
+            *__a0 = true;
+            __a0
+        };
         assert!(b);
     }
     return 0;

tests/unit/vector_bool_reference.cpp

@@ -1,4 +1,3 @@
-// XFAIL: refcount, unsafe
 #include <cassert>
 #include <vector>
 
@@ -14,11 +13,11 @@ int main() {
   assert(v1[0]);
   v1[0] = false;
   assert(!v1[0]);
-{
-  std::vector<bool> v = {false, false, false };
-  int i = 0;
-  bool b = v[i++] = true;
-  assert(b);
-}
+  {
+    std::vector<bool> v = {false, false, false};
+    int i = 0;
+    bool b = v[i++] = true;
+    assert(b);
+  }
   return 0;
 }