Add a missing annotation

And add some extra ref checking.  The rewriter didn't verify that it didn't
over-decref which made this hard to find.

src/asm_writing/rewriter.cpp

@@ -20,6 +20,7 @@
 #include "core/common.h"
 #include "core/stats.h"
 #include "runtime/types.h"
+#include "runtime/objmodel.h"
 
 namespace pyston {
 
@@ -567,6 +568,12 @@ void Rewriter::_decref(RewriterVar* var) {
 
     _setupCall(true, llvm::ArrayRef<RewriterVar*>(&var, 1), llvm::ArrayRef<RewriterVar*>(NULL, (int)0), assembler::RAX);
 
+
+#ifdef Py_REF_DEBUG
+    assembler->mov(assembler::Immediate((void*)assertAlive), assembler::R11);
+    assembler->callq(assembler::R11);
+    assembler->mov(assembler::RAX, assembler::RDI);
+#endif
     // _setupCall doesn't remember that it added the arg regs to the location set
     auto reg = assembler::RDI;
     //auto reg = var->getInReg();

src/runtime/builtin_modules/builtins.cpp

@@ -646,7 +646,8 @@ Box* setattrFunc(Box* obj, Box* _str, Box* value) {
     return incref(None);
 }
 
-static Box* hasattrFuncHelper(Box* return_val) noexcept {
+// Not sure if this should be stealing or not:
+static Box* hasattrFuncHelper(STOLEN(Box*) return_val) noexcept {
     AUTO_XDECREF(return_val);
 
     if (return_val)
@@ -744,6 +745,7 @@ Box* hasattrFuncInternal(BoxedFunctionBase* func, CallRewriteArgs* rewrite_args,
     if (rewrite_args) {
         RewriterVar* final_rtn
             = rewrite_args->rewriter->call(false, (void*)hasattrFuncHelper, r_rtn)->setType(RefType::OWNED);
+        r_rtn->refConsumed();
 
         if (S == CXX)
             rewrite_args->rewriter->checkAndThrowCAPIException(final_rtn);

src/runtime/objmodel.cpp

@@ -6950,4 +6950,8 @@ extern "C" void boxedLocalsDel(Box* boxedLocals, BoxedString* attr) {
 extern "C" void checkRefs(Box* b) {
     RELEASE_ASSERT(b->ob_refcnt >= 0, "%ld", b->ob_refcnt);
 }
+extern "C" Box* assertAlive(Box* b) {
+    RELEASE_ASSERT(b->ob_refcnt > 0, "%ld", b->ob_refcnt);
+    return b;
+}
 }

src/runtime/objmodel.h

@@ -226,6 +226,7 @@ extern "C" void boxedLocalsSet(Box* boxedLocals, BoxedString* attr, Box* val);
 extern "C" Box* boxedLocalsGet(Box* boxedLocals, BoxedString* attr, Box* globals);
 extern "C" void boxedLocalsDel(Box* boxedLocals, BoxedString* attr);
 
-extern "C" void checkRefs(Box* b);
+extern "C" void checkRefs(Box* b);   // asserts that b has >= 0 refs
+extern "C" Box* assertAlive(Box* b); // asserts that b has > 0 refs, and returns b
 }
 #endif