diff --git a/cpp2rust/converter/converter.cpp b/cpp2rust/converter/converter.cpp
index 5f4ce08e..9ba109d2 100644
--- a/cpp2rust/converter/converter.cpp
+++ b/cpp2rust/converter/converter.cpp
@@ -2235,7 +2235,7 @@ void Converter::ConvertBinaryOperator(clang::BinaryOperator *expr) {
       auto op = opcode_as_string;
       op.remove_suffix(1); // remove '=' from operator
       StrCat(op);
-      Convert(rhs);
+      Convert(rhs, computation_result_type);
     }
     if (lhs_type->isBooleanType()) {
       StrCat(token::kDiff, token::kZero);
diff --git a/tests/unit/out/refcount/size_t_ssize_t.rs b/tests/unit/out/refcount/size_t_ssize_t.rs
index 24e72ffc..e45737c4 100644
--- a/tests/unit/out/refcount/size_t_ssize_t.rs
+++ b/tests/unit/out/refcount/size_t_ssize_t.rs
@@ -211,5 +211,14 @@ fn main_0() -> i32 {
         (((*sz.borrow()) as isize) - ((*ul.borrow()) as isize)),
     ));
     assert!(((*delta.borrow()) == 11_isize));
+    let a64: Value<i64> = Rc::new(RefCell::new(100_i64));
+    let b: Value<isize> = Rc::new(RefCell::new(30_isize));
+    (*a64.borrow_mut()) -= ((*b.borrow()) as i64);
+    assert!(((*a64.borrow()) == 70_i64));
+    (*a64.borrow_mut()) += ((*b.borrow()) as i64);
+    assert!(((*a64.borrow()) == 100_i64));
+    let c: Value<isize> = Rc::new(RefCell::new((-20_i32 as isize)));
+    (*a64.borrow_mut()) -= ((*c.borrow()) as i64);
+    assert!(((*a64.borrow()) == 120_i64));
     return (((*n.borrow()).wrapping_rem(7_usize)) as i32);
 }
diff --git a/tests/unit/out/unsafe/size_t_ssize_t.rs b/tests/unit/out/unsafe/size_t_ssize_t.rs
index dab5949d..1c5755f8 100644
--- a/tests/unit/out/unsafe/size_t_ssize_t.rs
+++ b/tests/unit/out/unsafe/size_t_ssize_t.rs
@@ -156,5 +156,14 @@ unsafe fn main_0() -> i32 {
     assert!(((smax) == (15_isize)));
     let mut delta: isize = ((sz as isize) - (ul as isize));
     assert!(((delta) == (11_isize)));
+    let mut a64: i64 = 100_i64;
+    let mut b: isize = 30_isize;
+    a64 -= (b as i64);
+    assert!(((a64) == (70_i64)));
+    a64 += (b as i64);
+    assert!(((a64) == (100_i64)));
+    let mut c: isize = (-20_i32 as isize);
+    a64 -= (c as i64);
+    assert!(((a64) == (120_i64)));
     return (((n).wrapping_rem(7_usize)) as i32);
 }
diff --git a/tests/unit/size_t_ssize_t.cpp b/tests/unit/size_t_ssize_t.cpp
index dbcbcc32..e07f8f52 100644
--- a/tests/unit/size_t_ssize_t.cpp
+++ b/tests/unit/size_t_ssize_t.cpp
@@ -85,5 +85,16 @@ int main() {
   ssize_t delta = (ssize_t)sz - (ssize_t)ul;
   assert(delta == 11);
 
+  typedef long long ll_t;
+  ll_t a64 = 100;
+  ssize_t b = 30;
+  a64 -= b;
+  assert(a64 == 70);
+  a64 += b;
+  assert(a64 == 100);
+  ssize_t c = -20;
+  a64 -= c;
+  assert(a64 == 120);
+
   return (int)(n % 7);
 }