diff --git a/aot/options.cpp b/aot/options.cpp
index fc52aed9d99f8a484503ce2a6203ff28e24b10a5..0ee6c366ca597754f641a7ef39ac12bd4e010450 100644
--- a/aot/options.cpp
+++ b/aot/options.cpp
@@ -61,6 +61,11 @@ bool Options::Parse(int argc, const char **argv)
     panda::PandArg<std::string> stdLib("stdlib", "", "Path to standard library");
     panda::PandArg<bool> genStdLib("gen-stdlib", false, "Gen standard library");
     panda::PandArg<std::string> arktsConfig("arktsconfig", DEFAULT_ARKTSCONFIG, "Path to arkts configuration file");
+#ifndef PANDA_PRODUCT_BUILD
+    panda::PandArg<bool> allowTestingBuiltinsSyntax(
+        "allow-testing-builtins-syntax", false,
+        "Allow testing builtins syntax (i.e. convert `%Foo` to `RuntimeTesting.Foo`)");
+#endif  // PANDA_PRODUCT_BUILD
 
     // tail arguments
     panda::PandArg<std::string> inputFile("input", "", "input file");
@@ -83,6 +88,9 @@ bool Options::Parse(int argc, const char **argv)
     argparser_->Add(&stdLib);
     argparser_->Add(&genStdLib);
     argparser_->Add(&arktsConfig);
+#ifndef PANDA_PRODUCT_BUILD
+    argparser_->Add(&allowTestingBuiltinsSyntax);
+#endif  // PANDA_PRODUCT_BUILD
 
     argparser_->PushBackTail(&inputFile);
     argparser_->EnableTail();
@@ -196,6 +204,9 @@ bool Options::Parse(int argc, const char **argv)
     compilerOptions_.std_lib = stdLib.GetValue();
     compilerOptions_.gen_std_lib = genStdLib.GetValue();
     compilerOptions_.arkts_config = arktsConfig.GetValue();
+#ifndef PANDA_PRODUCT_BUILD
+    compilerOptions_.allow_testing_builtins_syntax = allowTestingBuiltinsSyntax.GetValue();
+#endif  // PANDA_PRODUCT_BUILD
 
     return true;
 }
diff --git a/binder/scope.cpp b/binder/scope.cpp
index a7c0a73d20b69646d22abefd7e0aeb2f49a035c3..99ecac201e0430ce1f4665fce043e8e3dde2f034 100644
--- a/binder/scope.cpp
+++ b/binder/scope.cpp
@@ -256,7 +256,7 @@ void VariableScope::CheckDirectEval(compiler::CompilerContext *compilerCtx)
         }
     }
 
-    std::vector<compiler::Literal> literals(LexicalSlots() + constBindings);
+    std::vector<compiler::Literal> literals(LexicalSlots() + constBindings, compiler::Literal(util::StringView()));
 
     if (constBindings == 0U) {
         for (const auto &[name, variable] : bindings_) {
@@ -280,6 +280,11 @@ void VariableScope::CheckDirectEval(compiler::CompilerContext *compilerCtx)
 
         uint32_t buffIndex = 0;
         for (const auto *variable : bindings) {
+            if (variable == nullptr) {
+                ASSERT(literals[buffIndex].GetString() == "");
+                buffIndex++;
+                continue;
+            }
             if (variable->Declaration()->IsConstDecl()) {
                 literals[buffIndex++] = compiler::Literal(true);
             }
diff --git a/compiler/core/emitter.cpp b/compiler/core/emitter.cpp
index b8bfc9670d8140199b9c2d46cf6d8f62db0e23d0..ccfbaca1ea218c540a0fda1d4a72d1b475c23209 100644
--- a/compiler/core/emitter.cpp
+++ b/compiler/core/emitter.cpp
@@ -98,7 +98,7 @@ static LiteralPair TransformLiteral(const compiler::Literal *literal)
             break;
         }
         default:
-            break;
+            UNREACHABLE();
     }
 
     tagLit.tag = panda_file::LiteralTag::TAGVALUE;
diff --git a/es2panda.h b/es2panda.h
index 0eae7cfd5d7da98ee94a965229c35f307b9c93b6..96387965b2c87bd6704c9d2920ad19dc4c081ed7 100644
--- a/es2panda.h
+++ b/es2panda.h
@@ -64,6 +64,9 @@ struct CompilerOptions {
     bool is_eval {};
     bool is_direct_eval {};
     bool is_function_eval {};
+#ifndef PANDA_PRODUCT_BUILD
+    bool allow_testing_builtins_syntax {};
+#endif  // PANDA_PRODUCT_BUILD
     bool dump_ast {};
     bool dump_asm {};
     bool dump_debug_info {};
diff --git a/parser/expressionParser.cpp b/parser/expressionParser.cpp
index 50dff800db1e23d1260c0a1951e2401d14cd3873..4268e1d950af8ff4d58372b13d5e51d1f84b6e9c 100644
--- a/parser/expressionParser.cpp
+++ b/parser/expressionParser.cpp
@@ -1012,6 +1012,21 @@ ir::Expression *ParserImpl::ParsePrimaryExpression(ExpressionParseFlags flags)
         case lexer::TokenType::PUNCTUATOR_LESS_THAN: {
             return ParsePrefixAssertionExpression();
         }
+#ifndef PANDA_PRODUCT_BUILD
+        case lexer::TokenType::PUNCTUATOR_MOD: {
+            if (options_.allow_testing_builtins_syntax) {
+                util::UString implicitObject(std::string("RuntimeTesting"), Allocator());
+                auto *implicitObj = AllocNode<ir::Identifier>(implicitObject.View(), Allocator());
+                implicitObj->SetReference();
+                implicitObj->SetRange(lexer_->GetToken().Loc());
+
+                lexer_->NextToken();
+                return ParsePropertyAccess(implicitObj);
+            } else {
+                ThrowSyntaxError({"Testing builtins syntax is not allowed"});
+            }
+        }
+#endif  // PANDA_PRODUCT_BUILD
         default: {
             break;
         }