Method signatures

bolt/expression/tests/ExprTest.cpp:1484–1492

  }

  static std::vector<std::shared_ptr<exec::FunctionSignature>> signatures() {
    // T... -> integer
    return {exec::FunctionSignatureBuilder()
                .typeVariable("T")
                .returnType("integer")
                .argumentType("T")
                .variableArity()
                .build()};
  }

 private:
  const int32_t numInputs_;