Added exception message for '//' operator
Added exception message for '//' operator


Former-commit-id: 3825b7164f1eca65bd51d43f34d19efdb7d9c3ce
darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide