Merge pull request #9865 from ethereum/dissalow-explicit-conversion-to-address

[BREAKING] Disallow explicit conversions from negative literals to ``address``

Changelog.md

@@ -2,6 +2,7 @@
 
 Breaking Changes:
  * Type System: Unary negation can only be used on signed integers, not on unsigned integers.
+ * Type System: Disallow explicit conversions from negative literals and literals larger than ``type(uint160).max`` to ``address`` type.
 
 Compiler Features:
  * SMTChecker: Support ``addmod`` and ``mulmod``.

docs/080-breaking-changes.rst

@@ -0,0 +1,17 @@
+********************************
+Solidity v0.8.0 Breaking Changes
+********************************
+
+This section highlights the main breaking changes introduced in Solidity
+version 0.8.0, along with the reasoning behind the changes and how to update
+affected code.
+For the full list check
+`the release changelog <https://github.com/ethereum/solidity/releases/tag/v0.8.0>`_.
+
+Semantic and Syntactic Changes
+==============================
+
+This section lists changes where you have to modify your code
+and it does something else afterwards.
+
+* Explicit conversions from negative literals and literals larger than ``type(uint160).max`` to ``address`` are now disallowed.

docs/index.rst

@@ -128,6 +128,7 @@ Contents
    050-breaking-changes.rst
    060-breaking-changes.rst
    070-breaking-changes.rst
+   080-breaking-changes.rst
    natspec-format.rst
    security-considerations.rst
    resources.rst

docs/using-the-compiler.rst

@@ -613,8 +613,8 @@ Available upgrade modules
 +----------------------------+---------+--------------------------------------------------+
 
 Please read :doc:`0.5.0 release notes <050-breaking-changes>`,
-:doc:`0.6.0 release notes <060-breaking-changes>` and
-:doc:`0.7.0 release notes <070-breaking-changes>` for further details.
+:doc:`0.6.0 release notes <060-breaking-changes>`,
+:doc:`0.7.0 release notes <070-breaking-changes>` and :doc:`0.8.0 release notes <080-breaking-changes>` for further details.
 
 Synopsis
 ~~~~~~~~

libsolidity/ast/Types.cpp

@@ -963,13 +963,17 @@ BoolResult RationalNumberType::isExplicitlyConvertibleTo(Type const& _convertTo)
 {
 	if (isImplicitlyConvertibleTo(_convertTo))
 		return true;
-	else if (_convertTo.category() != Category::FixedBytes)
-	{
-		TypePointer mobType = mobileType();
-		return (mobType && mobType->isExplicitlyConvertibleTo(_convertTo));
-	}
-	else
+
+	auto category = _convertTo.category();
+	if (category == Category::FixedBytes)
 		return false;
+	if (category == Category::Address)
+		if (isNegative() || isFractional() || integerType()->numBits() > 160)
+			return false;
+
+	TypePointer mobType = mobileType();
+	return (mobType && mobType->isExplicitlyConvertibleTo(_convertTo));
+
 }
 
 TypeResult RationalNumberType::unaryOperatorResult(Token _operator) const

test/libsolidity/semanticTests/types/type_conversion_cleanup.sol

@@ -1,7 +1,7 @@
 contract Test {
-    function test() public returns (uint ret) { return uint(address(Test(address(0x11223344556677889900112233445566778899001122)))); }
+    function test() public returns (uint ret) { return uint(address(uint128(0x11223344556677889900112233445566778899001122))); }
 }
 // ====
 // compileViaYul: also
 // ----
-// test() -> 0x0000000000000000000000003344556677889900112233445566778899001122
+// test() -> 158887387085137674884660775897412931874

test/libsolidity/smtCheckerTests/typecast/same_size.sol

@@ -17,9 +17,9 @@ contract C {
 		assert(t == 200);
 		int256 v = int256(bytes32(uint256(2**255 + 10)));
 		assert(v == -(2**255) + 10);
-		int160 a = int160(address(-1));
+		int160 a = int160(address(type(uint160).max));
 		assert(a == -1);
-		int160 b = int160(address(2**159 + 10));
+		int160 b = int160(address(uint(2**159 + 10)));
 		assert(b == -(2**159) + 10);
 		D d;
 		int160 e = int160(address(d));
@@ -42,7 +42,7 @@ contract C {
 		assert(w == 2**256 - 2);
 		bytes4 b = bytes4(uint32(-2));
 		assert(uint32(b) == uint32(2**32 - 2));
-		address a = address(-1);
+		address a = address(type(uint160).max);
 		assert(uint160(a) == uint160(2**160 - 1));
 		address c = address(0);
 		assert(uint160(c) == 0);
@@ -71,4 +71,4 @@ contract C {
 	}
 }
 // ----
-// Warning 8364: (1304-1305): Assertion checker does not yet implement type type(enum E)
+// Warning 8364: (1340-1341): Assertion checker does not yet implement type type(enum E)

test/libsolidity/syntaxTests/types/address/conversion.sol

@@ -0,0 +1,9 @@
+contract C {
+    function f() public pure returns (address) {
+        return address(2**160 -1);
+    }
+    function g() public pure returns (address) {
+        return address(uint(-1));
+    }
+}
+// ----

test/libsolidity/syntaxTests/types/address/conversion_error.sol

@@ -0,0 +1,15 @@
+contract C {
+    function f() public pure returns (address) {
+        return address(-1);
+    }
+    function g() public pure returns (address) {
+        return -1;
+    }
+	function h() public pure returns (address) {
+		return address(2**160);
+	}
+}
+// ----
+// TypeError 9640: (77-88): Explicit type conversion not allowed from "int_const -1" to "address".
+// TypeError 6359: (160-162): Return argument type int_const -1 is not implicitly convertible to expected type (type of first return variable) address.
+// TypeError 9640: (225-240): Explicit type conversion not allowed from "int_const 1461...(41 digits omitted)...2976" to "address".