Merge pull request #10224 from ethereum/strict-literal-to-enum-conversion

[BREAKING] Strict explicit conversion between literals and enums

test/libsolidity/semanticTests/enums/enum_explicit_overflow.sol

@@ -13,8 +13,8 @@ contract test {
         d = uint256(choice);
     }
 
-    function getChoiceFromNegativeLiteral() public returns (uint256 d) {
-        choice = ActionChoices(-1);
+    function getChoiceFromMax() public returns (uint256 d) {
+        choice = ActionChoices(type(uint).max);
         d = uint256(choice);
     }
 
@@ -25,8 +25,9 @@ contract test {
 // compileViaYul: also
 // EVMVersion: >=byzantium
 // ----
+// getChoiceExp(uint256): 2 -> 2
 // getChoiceExp(uint256): 3 -> FAILURE, hex"4e487b71", 33 # These should throw #
 // getChoiceFromSigned(int256): -1 -> FAILURE, hex"4e487b71", 33
-// getChoiceFromNegativeLiteral() -> FAILURE, hex"4e487b71", 33
+// getChoiceFromMax() -> FAILURE, hex"4e487b71", 33
 // getChoiceExp(uint256): 2 -> 2 # These should work #
 // getChoiceExp(uint256): 0 -> 0

test/libsolidity/semanticTests/enums/enum_explicit_overflow_homestead.sol

@@ -13,8 +13,8 @@ contract test {
         d = uint256(choice);
     }
 
-    function getChoiceFromNegativeLiteral() public returns (uint256 d) {
-        choice = ActionChoices(-1);
+    function getChoiceFromMax() public returns (uint256 d) {
+        choice = ActionChoices(type(uint256).max);
         d = uint256(choice);
     }
 
@@ -27,6 +27,6 @@ contract test {
 // ----
 // getChoiceExp(uint256): 3 -> FAILURE # These should throw #
 // getChoiceFromSigned(int256): -1 -> FAILURE
-// getChoiceFromNegativeLiteral() -> FAILURE
+// getChoiceFromMax() -> FAILURE
 // getChoiceExp(uint256): 2 -> 2 # These should work #
 // getChoiceExp(uint256): 0 -> 0

test/libsolidity/syntaxTests/enums/literal_conversion.sol

@@ -0,0 +1,10 @@
+contract C {
+    enum Test { One, Two }
+    function f() public pure {
+        Test a = Test(0);
+        Test b = Test(1);
+        Test c = Test(type(uint).max);
+        a; b; c;
+    }
+}
+// ----

test/libsolidity/syntaxTests/enums/literal_conversion_error.sol

@@ -0,0 +1,16 @@
+contract C {
+    enum Test { One, Two }
+    function f() public {
+        Test(-1);
+        Test(2);
+        Test(13);
+        Test(5/3);
+        Test(0.5);
+    }
+}
+// ----
+// TypeError 9640: (74-82): Explicit type conversion not allowed from "int_const -1" to "enum C.Test".
+// TypeError 9640: (92-99): Explicit type conversion not allowed from "int_const 2" to "enum C.Test".
+// TypeError 9640: (109-117): Explicit type conversion not allowed from "int_const 13" to "enum C.Test".
+// TypeError 9640: (127-136): Explicit type conversion not allowed from "rational_const 5 / 3" to "enum C.Test".
+// TypeError 9640: (146-155): Explicit type conversion not allowed from "rational_const 1 / 2" to "enum C.Test".