add a semantic test for masks

Author: Mohammad Rezaei

test/libsolidity/semanticTests/constants/mask_tests.sol

@@ -0,0 +1,78 @@
+// test various masks, some generated by the compiler internally
+
+contract MaskTests {
+    struct FitsInU256 {
+        uint8 oneByte;
+        uint96 bigNightySixer;
+        uint64 sixtyFourMiddle;
+        uint16 sixteener;
+        uint72 seventyTwo;
+    }
+
+    FitsInU256 first;
+
+    constructor() {
+        first = FitsInU256(0x98, 0x010203040506070809a1b2c3, 0xdeadcafefeedbead, 0x1234, 0x102030405060708090);
+    }
+
+    // the compiler generates masks for these functions
+    function firstOneByte() external view returns (uint8) {
+        return first.oneByte;
+    }
+
+    function firstBigNightySixer() external view returns (uint96) {
+        return first.bigNightySixer;
+    }
+
+    function firstSixtyFourMiddle() external view returns (uint64) {
+        return first.sixtyFourMiddle;
+    }
+
+    function firstSixteener() external view returns (uint16) {
+        return first.sixteener;
+    }
+
+    function firstSeventyTwo() external view returns (uint72) {
+        return first.seventyTwo;
+    }
+
+    function setMiddleSixtyFour(uint64 x) external returns (uint96) {
+        first.sixtyFourMiddle = x;
+        return first.bigNightySixer + first.sixtyFourMiddle + first.sixteener;
+    }
+
+    // hand coded masks
+    function add55(uint x) external pure returns (uint) {
+        return x + ((uint(1) << 55) - 1);
+    }
+
+    function add155(uint x) external pure returns (uint) {
+        return x + ((uint(1) << 155) - 1);
+    }
+
+    function add55shift(uint x) external pure returns (uint) {
+        return x + (((uint(1) << 55) - 1) << 67);
+    }
+
+    function add155shift(uint x) external pure returns (uint) {
+        return x + (((uint(1) << 155) - 1) << 67);
+    }
+}
+// ====
+// EVMVersion: =current
+// ----
+// firstOneByte() -> 0x98
+// firstBigNightySixer() -> 0x010203040506070809a1b2c3
+// firstSixtyFourMiddle() -> 0xdeadcafefeedbead
+// firstSixteener() -> 0x1234
+// firstSeventyTwo() -> 0x102030405060708090
+// add55(uint256): 1 -> 0x80000000000000
+// add55(uint256): 2 -> 0x80000000000001
+// add55(uint256): 0x1000000000000000 -> 0x107fffffffffffff
+// add155(uint256): 1 -> 0x800000000000000000000000000000000000000
+// add55shift(uint256): 1 -> 0x3fffffffffffff80000000000000001
+// add55shift(uint256): 0x80000000000000000 -> 0x4000000000000000000000000000000
+// add155shift(uint256): 1 -> 0x3ffffffffffffffffffffffffffffffffffffff80000000000000001
+// add155shift(uint256): 0x80000000000000000 -> 0x40000000000000000000000000000000000000000000000000000000
+// setMiddleSixtyFour(uint64): 0 -> 0x010203040506070809a1c4f7
+// setMiddleSixtyFour(uint64): 0xffffffffffffffff -> 0x010203050506070809a1c4f6