pragma experimental ABIEncoderV2; contract C { function g(address x) external pure returns (uint256 r) { assembly { r := x } } function f(uint256 a) external view returns (uint256) { address x; assembly { x := a } return this.g(x); } } // ---- // f(uint256): 0 -> 0 // g(address): 0 -> 0 # test validation as well as sanity check # // f(uint256): 1 -> 1 // g(address): 1 -> 1 // f(uint256): 2 -> 2 // g(address): 2 -> 2 // f(uint256): 0xabcdef0123456789abcdef0123456789abcdefff -> 0xabcdef0123456789abcdef0123456789abcdefff // g(address): 0xabcdef0123456789abcdef0123456789abcdefff -> 0xabcdef0123456789abcdef0123456789abcdefff // f(uint256): 0xffffffffffffffffffffffffffffffffffffffff -> 0xffffffffffffffffffffffffffffffffffffffff // g(address): 0xffffffffffffffffffffffffffffffffffffffff -> 0xffffffffffffffffffffffffffffffffffffffff // f(uint256): 0x010000000000000000000000000000000000000000 -> 0 // g(address): 0x010000000000000000000000000000000000000000 -> FAILURE // f(uint256): 0x01abcdef0123456789abcdef0123456789abcdefff -> 0xabcdef0123456789abcdef0123456789abcdefff // g(address): 0x01abcdef0123456789abcdef0123456789abcdefff -> FAILURE // f(uint256): 0x01ffffffffffffffffffffffffffffffffffffffff -> 0xffffffffffffffffffffffffffffffffffffffff // g(address): 0x01ffffffffffffffffffffffffffffffffffffffff -> FAILURE // f(uint256): -1 -> 0xffffffffffffffffffffffffffffffffffffffff // g(address): -1 -> FAILURE