Print warning for unnamed return parameters and no return statement

test/cmdlineTests/optimizer_array_sload/input.sol

@@ -4,8 +4,8 @@ pragma solidity >=0.0;
 contract Arraysum {
 	uint256[] values;
 
-	function sumArray() public view returns(uint) {
-		uint sum = 0;
+	function sumArray() public view returns(uint sum) {
+		sum = 0;
 		// The optimizer should read the length of the array only once, because
 		// LoopInvariantCodeMotion can move the `sload` corresponding to the length outside of the
 		// loop.

test/cmdlineTests/optimizer_array_sload/output

@@ -43,7 +43,7 @@ object "Arraysum_33" {
                             vloc_sum := add(vloc_sum, _3)
                         }
                         let memPos := allocateMemory(_1)
-                        return(memPos, sub(abi_encode_uint(memPos, _1), memPos))
+                        return(memPos, sub(abi_encode_uint(memPos, vloc_sum), memPos))
                     }
                 }
                 revert(0, 0)