Fix fn-ptr void-cast clone: skip only for fresh expressions, not variable refs

Author: Copilot

cpp2rust/converter/models/converter_refcount.cpp

@@ -1322,8 +1322,16 @@ bool ConverterRefCount::VisitExplicitCastExpr(clang::ExplicitCastExpr *expr) {
   if (expr->getTypeAsWritten()->isVoidType()) {
     PushExprKind push(*this, ExprKind::Void);
     Convert(expr->getSubExpr());
+    // Skip .clone() for fresh fn-ptr values (cast/constructor results).
+    // Variable references to fn-ptrs still need .clone() because FnPtr is
+    // non-Copy and (*var.borrow()) would otherwise attempt a move.
+    auto *inner = expr->getSubExpr()->IgnoreParenImpCasts();
+    bool is_fn_ptr_var_ref =
+        clang::isa<clang::DeclRefExpr>(inner) &&
+        inner->getType()->isFunctionPointerType();
     if (!TypeIsCopyable(expr->getSubExpr()->getType()) &&
-        !expr->getSubExpr()->getType()->isFunctionPointerType()) {
+        (!expr->getSubExpr()->getType()->isFunctionPointerType() ||
+         is_fn_ptr_var_ref)) {
       StrCat(".clone()");
     }
     return false;

tests/unit/out/refcount/va_arg_fn_ptr.rs

@@ -47,7 +47,7 @@ pub fn not_supported_5(ctx: AnyPtr, fn_: FnPtr<fn(i32) -> i32>, extra: AnyPtr) -
     let fn_: Value<FnPtr<fn(i32) -> i32>> = Rc::new(RefCell::new(fn_));
     let extra: Value<AnyPtr> = Rc::new(RefCell::new(extra));
     (*ctx.borrow()).clone();
-    (*fn_.borrow());
+    (*fn_.borrow()).clone();
     (*extra.borrow()).clone();
     return -3_i32;
 }