// This used to work pre-0.6.0. library L { function f() public returns(uint[] storage); function g() public returns(uint[] storage s); } abstract library T { function f() public returns(uint[] storage); function g() public returns(uint[] storage s); } // ---- // TypeError 9571: (146-268): Libraries cannot be abstract. // TypeError 9231: (48-92): Library functions must be implemented if declared. // TypeError 9231: (97-143): Library functions must be implemented if declared. // TypeError 9231: (171-215): Library functions must be implemented if declared. // TypeError 9231: (220-266): Library functions must be implemented if declared.