Merge pull request #4093 from ethereum/prepareDropConstantKeyword

Prepare drop constant keyword.

20 files changed, 110 insertions, 125 deletions

diff --git a/Changelog.md b/Changelog.md
index 9004dc29..dfa24a25 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,6 +1,7 @@
 ### 0.4.24 (unreleased)
 
 Features:
+ * Remove deprecated ``constant`` as function state modifier from documentation and tests (but still leave it as a valid feature).
  * Build System: Update internal dependency of jsoncpp to 1.8.4, which introduces more strictness and reduces memory usage.
  * Code Generator: Use native shift instructions on target Constantinople.
  * Gas Estimator: Only explore paths with higher gas costs. This reduces accuracy but greatly improves the speed of gas estimation.
diff --git a/docs/contracts.rst b/docs/contracts.rst
index 3576cd7b..487e80ae 100644
--- a/docs/contracts.rst
+++ b/docs/contracts.rst
@@ -473,7 +473,7 @@ The following statements are considered modifying the state:
     }
 
 .. note::
-  ``constant`` on functions is an alias to ``view``, but this is deprecated and is planned to be dropped in version 0.5.0.
+  ``constant`` on functions is an alias to ``view``, but this is deprecated and will be dropped in version 0.5.0.
 
 .. note::
   Getter methods are marked ``view``.
diff --git a/docs/introduction-to-smart-contracts.rst b/docs/introduction-to-smart-contracts.rst
index 84b1fff8..d1789c44 100644
--- a/docs/introduction-to-smart-contracts.rst
+++ b/docs/introduction-to-smart-contracts.rst
@@ -25,7 +25,7 @@ Storage
             storedData = x;
         }
 
-        function get() public constant returns (uint) {
+        function get() public view returns (uint) {
             return storedData;
         }
     }
diff --git a/docs/security-considerations.rst b/docs/security-considerations.rst
index 3e1c3a12..4133edb1 100644
--- a/docs/security-considerations.rst
+++ b/docs/security-considerations.rst
@@ -120,7 +120,7 @@ Gas Limit and Loops
 Loops that do not have a fixed number of iterations, for example, loops that depend on storage values, have to be used carefully:
 Due to the block gas limit, transactions can only consume a certain amount of gas. Either explicitly or just due to
 normal operation, the number of iterations in a loop can grow beyond the block gas limit which can cause the complete
-contract to be stalled at a certain point. This may not apply to ``constant`` functions that are only executed
+contract to be stalled at a certain point. This may not apply to ``view`` functions that are only executed
 to read data from the blockchain. Still, such functions may be called by other contracts as part of on-chain operations
 and stall those. Please be explicit about such cases in the documentation of your contracts.
 
diff --git a/docs/style-guide.rst b/docs/style-guide.rst
index 0c58f3eb..6b28f2ab 100644
--- a/docs/style-guide.rst
+++ b/docs/style-guide.rst
@@ -269,7 +269,7 @@ Functions should be grouped according to their visibility and ordered:
 - internal
 - private
 
-Within a grouping, place the ``constant`` functions last.
+Within a grouping, place the ``view`` and ``pure`` functions last.
 
 Yes::
 
@@ -285,7 +285,10 @@ Yes::
         // External functions
         // ...
 
-        // External functions that are constant
+        // External functions that are view
+        // ...
+
+        // External functions that are pure
         // ...
 
         // Public functions
diff --git a/std/StandardToken.sol b/std/StandardToken.sol
index ca0658f2..c2fc3a66 100644
--- a/std/StandardToken.sol
+++ b/std/StandardToken.sol
@@ -13,11 +13,11 @@ contract StandardToken is Token {
 		balance[_initialOwner] = _supply;
 	}
 
-	function balanceOf(address _account) constant public returns (uint) {
+	function balanceOf(address _account) view public returns (uint) {
 		return balance[_account];
 	}
 
-	function totalSupply() constant public returns (uint) {
+	function totalSupply() view public returns (uint) {
 		return supply;
 	}
 
@@ -53,7 +53,7 @@ contract StandardToken is Token {
 		return true;
 	}
 
-	function allowance(address _owner, address _spender) constant public returns (uint256) {
+	function allowance(address _owner, address _spender) view public returns (uint256) {
 		return m_allowance[_owner][_spender];
 	}
 }
diff --git a/std/Token.sol b/std/Token.sol
index 4b4eb71e..7348a8f5 100644
--- a/std/Token.sol
+++ b/std/Token.sol
@@ -4,10 +4,10 @@ contract Token {
 	event Transfer(address indexed _from, address indexed _to, uint256 _value);
 	event Approval(address indexed _owner, address indexed _spender, uint256 _value);
 
-	function totalSupply() constant public returns (uint256 supply);
-	function balanceOf(address _owner) constant public returns (uint256 balance);
+	function totalSupply() view public returns (uint256 supply);
+	function balanceOf(address _owner) view public returns (uint256 balance);
 	function transfer(address _to, uint256 _value) public returns (bool success);
 	function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
 	function approve(address _spender, uint256 _value) public returns (bool success);
-	function allowance(address _owner, address _spender) constant public returns (uint256 remaining);
+	function allowance(address _owner, address _spender) view public returns (uint256 remaining);
 }
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index 3a4a2dad..4b09d253 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -2105,7 +2105,7 @@ BOOST_AUTO_TEST_CASE(packed_keccak256_complex_types)
 	char const* sourceCode = R"(
 		contract test {
 			uint120[3] x;
-			function f() view returns (bytes32 hash1, bytes32 hash2, bytes32 hash3) {
+			function f() returns (bytes32 hash1, bytes32 hash2, bytes32 hash3) {
 				uint120[] memory y = new uint120[](3);
 				x[0] = y[0] = uint120(-2);
 				x[1] = y[1] = uint120(-3);
@@ -10877,9 +10877,9 @@ BOOST_AUTO_TEST_CASE(negative_stack_height)
 				bool Aboolc;
 				bool exists;
 			}
-			function nredit(uint startindex) public constant returns(uint[500] CIDs, uint[500] dates, uint[500] RIDs, bool[500] Cboolas, uint[500] amounts){}
-			function return500InvoicesByDates(uint begindate, uint enddate, uint startindex) public constant returns(uint[500] AIDs, bool[500] Aboolas, uint[500] dates, bytes32[3][500] Abytesas, bytes32[3][500] bytesbs, bytes32[2][500] bytescs, uint[500] amounts, bool[500] Aboolbs, bool[500] Aboolcs){}
-			function return500PaymentsByDates(uint begindate, uint enddate, uint startindex) public constant returns(uint[500] BIDs, uint[500] dates, uint[500] RIDs, bool[500] Bboolas, bytes32[3][500] bytesbs,bytes32[2][500] bytescs, uint[500] amounts, bool[500] Bboolbs){}
+			function nredit(uint startindex) public pure returns(uint[500] CIDs, uint[500] dates, uint[500] RIDs, bool[500] Cboolas, uint[500] amounts){}
+			function return500InvoicesByDates(uint begindate, uint enddate, uint startindex) public view returns(uint[500] AIDs, bool[500] Aboolas, uint[500] dates, bytes32[3][500] Abytesas, bytes32[3][500] bytesbs, bytes32[2][500] bytescs, uint[500] amounts, bool[500] Aboolbs, bool[500] Aboolcs){}
+			function return500PaymentsByDates(uint begindate, uint enddate, uint startindex) public view returns(uint[500] BIDs, uint[500] dates, uint[500] RIDs, bool[500] Bboolas, bytes32[3][500] bytesbs,bytes32[2][500] bytescs, uint[500] amounts, bool[500] Bboolbs){}
 		}
 	)";
 	compileAndRun(sourceCode, 0, "C");
@@ -11065,13 +11065,13 @@ BOOST_AUTO_TEST_CASE(bare_call_invalid_address)
 	char const* sourceCode = R"(
 		contract C {
 			/// Calling into non-existant account is successful (creates the account)
-			function f() external view returns (bool) {
+			function f() external returns (bool) {
 				return address(0x4242).call();
 			}
-			function g() external view returns (bool) {
+			function g() external returns (bool) {
 				return address(0x4242).callcode();
 			}
-			function h() external view returns (bool) {
+			function h() external returns (bool) {
 				return address(0x4242).delegatecall();
 			}
 		}
@@ -11093,13 +11093,13 @@ BOOST_AUTO_TEST_CASE(delegatecall_return_value)
 			function get() external view returns (uint) {
 				return value;
 			}
-			function get_delegated() external view returns (bool) {
+			function get_delegated() external returns (bool) {
 				return this.delegatecall(bytes4(sha3("get()")));
 			}
 			function assert0() external view {
 				assert(value == 0);
 			}
-			function assert0_delegated() external view returns (bool) {
+			function assert0_delegated() external returns (bool) {
 				return this.delegatecall(bytes4(sha3("assert0()")));
 			}
 		}
@@ -11560,7 +11560,7 @@ BOOST_AUTO_TEST_CASE(abi_encode_v2)
 				require(y[0] == "e");
 			}
 			S s;
-			function f4() public view returns (bytes r) {
+			function f4() public returns (bytes r) {
 				string memory x = "abc";
 				s.a = 7;
 				s.b.push(2);
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index 91fd1fff..5af67659 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -831,24 +831,6 @@ BOOST_AUTO_TEST_CASE(illegal_override_visibility)
 	CHECK_ERROR(text, TypeError, "Overriding function visibility differs");
 }
 
-BOOST_AUTO_TEST_CASE(illegal_override_remove_constness)
-{
-	char const* text = R"(
-		contract B { function f() constant {} }
-		contract C is B { function f() public {} }
-	)";
-	CHECK_ERROR(text, TypeError, "Overriding function changes state mutability from \"view\" to \"nonpayable\".");
-}
-
-BOOST_AUTO_TEST_CASE(illegal_override_add_constness)
-{
-	char const* text = R"(
-		contract B { function f() public {} }
-		contract C is B { function f() constant {} }
-	)";
-	CHECK_ERROR(text, TypeError, "Overriding function changes state mutability from \"nonpayable\" to \"view\".");
-}
-
 BOOST_AUTO_TEST_CASE(complex_inheritance)
 {
 	char const* text = R"(
@@ -993,19 +975,6 @@ BOOST_AUTO_TEST_CASE(private_state_variable)
 	BOOST_CHECK_MESSAGE(function == nullptr, "Accessor function of an internal variable should not exist");
 }
 
-BOOST_AUTO_TEST_CASE(missing_state_variable)
-{
-	char const* text = R"(
-		contract Scope {
-			function getStateVar() constant public returns (uint stateVar) {
-				stateVar = Scope.stateVar; // should fail.
-			}
-		}
-	)";
-	CHECK_ERROR(text, TypeError, "Member \"stateVar\" not found or not visible after argument-dependent lookup in type(contract Scope)");
-}
-
-
 BOOST_AUTO_TEST_CASE(base_class_state_variable_accessor)
 {
 	// test for issue #1126 https://github.com/ethereum/cpp-ethereum/issues/1126
@@ -1119,17 +1088,6 @@ BOOST_AUTO_TEST_CASE(fallback_function_with_return_parameters)
 	CHECK_ERROR(text, TypeError, "Fallback function cannot return values.");
 }
 
-BOOST_AUTO_TEST_CASE(fallback_function_with_constant_modifier)
-{
-	char const* text = R"(
-		contract C {
-			uint x;
-			function() constant { x = 2; }
-		}
-	)";
-	CHECK_ERROR(text, TypeError, "Fallback function must be payable or non-payable");
-}
-
 BOOST_AUTO_TEST_CASE(fallback_function_twice)
 {
 	char const* text = R"(
@@ -2327,30 +2285,6 @@ BOOST_AUTO_TEST_CASE(constant_string_literal_disallows_assignment)
 	CHECK_ERROR(text, TypeError, "Index access for string is not possible.");
 }
 
-BOOST_AUTO_TEST_CASE(assign_constant_function_value_to_constant_0_4_x)
-{
-	char const* text = R"(
-		contract C {
-			function () constant returns (uint) x;
-			uint constant y = x();
-		}
-	)";
-	CHECK_WARNING(text, "Initial value for constant variable has to be compile-time constant.");
-}
-
-BOOST_AUTO_TEST_CASE(assign_constant_function_value_to_constant)
-{
-	char const* text = R"(
-		pragma experimental "v0.5.0";
-
-		contract C {
-			function () constant returns (uint) x;
-			uint constant y = x();
-		}
-	)";
-	CHECK_ERROR(text, TypeError, "Initial value for constant variable has to be compile-time constant.");
-}
-
 BOOST_AUTO_TEST_CASE(assignment_to_const_var_involving_conversion)
 {
 	char const* text = R"(
diff --git a/test/libsolidity/SolidityParser.cpp b/test/libsolidity/SolidityParser.cpp
index 77686b03..cbea8694 100644
--- a/test/libsolidity/SolidityParser.cpp
+++ b/test/libsolidity/SolidityParser.cpp
@@ -838,40 +838,6 @@ BOOST_AUTO_TEST_CASE(multiple_visibility_specifiers)
 	CHECK_PARSE_ERROR(text, "Visibility already specified as \"private\".");
 }
 
-BOOST_AUTO_TEST_CASE(multiple_statemutability_specifiers)
-{
-	char const* text = R"(
-		contract c {
-			function f() payable payable {}
-		})";
-	CHECK_PARSE_ERROR(text, "State mutability already specified as \"payable\".");
-	text = R"(
-		contract c {
-			function f() constant constant {}
-		})";
-	CHECK_PARSE_ERROR(text, "State mutability already specified as \"view\".");
-	text = R"(
-		contract c {
-			function f() constant view {}
-		})";
-	CHECK_PARSE_ERROR(text, "State mutability already specified as \"view\".");
-	text = R"(
-		contract c {
-			function f() payable constant {}
-		})";
-	CHECK_PARSE_ERROR(text, "State mutability already specified as \"payable\".");
-	text = R"(
-		contract c {
-			function f() pure payable {}
-		})";
-	CHECK_PARSE_ERROR(text, "State mutability already specified as \"pure\".");
-	text = R"(
-		contract c {
-			function f() pure constant {}
-		})";
-	CHECK_PARSE_ERROR(text, "State mutability already specified as \"pure\".");
-}
-
 BOOST_AUTO_TEST_CASE(literal_constants_with_ether_subdenominations)
 {
 	char const* text = R"(
diff --git a/test/libsolidity/syntaxTests/constants/assign_constant_function_value.sol b/test/libsolidity/syntaxTests/constants/assign_constant_function_value.sol
new file mode 100644
index 00000000..88e94e29
--- /dev/null
+++ b/test/libsolidity/syntaxTests/constants/assign_constant_function_value.sol
@@ -0,0 +1,6 @@
+contract C {
+    function () pure returns (uint) x;
+    uint constant y = x();
+}
+// ----
+// Warning: (74-77): Initial value for constant variable has to be compile-time constant. This will fail to compile with the next breaking version change.
diff --git a/test/libsolidity/syntaxTests/constants/assign_constant_function_value_050.sol b/test/libsolidity/syntaxTests/constants/assign_constant_function_value_050.sol
new file mode 100644
index 00000000..2c92899d
--- /dev/null
+++ b/test/libsolidity/syntaxTests/constants/assign_constant_function_value_050.sol
@@ -0,0 +1,8 @@
+pragma experimental "v0.5.0";
+
+contract C {
+    function () pure returns (uint) x;
+    uint constant y = x();
+}
+// ----
+// TypeError: (105-108): Initial value for constant variable has to be compile-time constant.
diff --git a/test/libsolidity/syntaxTests/fallback/pure_modifier.sol b/test/libsolidity/syntaxTests/fallback/pure_modifier.sol
new file mode 100644
index 00000000..20d5b0ac
--- /dev/null
+++ b/test/libsolidity/syntaxTests/fallback/pure_modifier.sol
@@ -0,0 +1,6 @@
+contract C {
+    uint x;
+    function() pure { x = 2; }
+}
+// ----
+// TypeError: (29-55): Fallback function must be payable or non-payable, but is "pure".
diff --git a/test/libsolidity/syntaxTests/fallback/view_modifier.sol b/test/libsolidity/syntaxTests/fallback/view_modifier.sol
new file mode 100644
index 00000000..44c5d204
--- /dev/null
+++ b/test/libsolidity/syntaxTests/fallback/view_modifier.sol
@@ -0,0 +1,6 @@
+contract C {
+    uint x;
+    function() view { x = 2; }
+}
+// ----
+// TypeError: (29-55): Fallback function must be payable or non-payable, but is "view".
diff --git a/test/libsolidity/syntaxTests/inheritance/override/add_view.sol b/test/libsolidity/syntaxTests/inheritance/override/add_view.sol
new file mode 100644
index 00000000..9973b23e
--- /dev/null
+++ b/test/libsolidity/syntaxTests/inheritance/override/add_view.sol
@@ -0,0 +1,4 @@
+contract B { function f() public {} }
+contract C is B { function f() view {} }
+// ----
+// TypeError: (56-76): Overriding function changes state mutability from "nonpayable" to "view".
diff --git a/test/libsolidity/syntaxTests/inheritance/override/remove_view.sol b/test/libsolidity/syntaxTests/inheritance/override/remove_view.sol
new file mode 100644
index 00000000..e58f6b20
--- /dev/null
+++ b/test/libsolidity/syntaxTests/inheritance/override/remove_view.sol
@@ -0,0 +1,4 @@
+contract B { function f() view {} }
+contract C is B { function f() public {} }
+// ----
+// TypeError: (54-76): Overriding function changes state mutability from "view" to "nonpayable".
diff --git a/test/libsolidity/syntaxTests/missing_state_variable.sol b/test/libsolidity/syntaxTests/missing_state_variable.sol
new file mode 100644
index 00000000..02082a45
--- /dev/null
+++ b/test/libsolidity/syntaxTests/missing_state_variable.sol
@@ -0,0 +1,7 @@
+contract Scope {
+    function getStateVar() view public returns (uint stateVar) {
+        stateVar = Scope.stateVar; // should fail.
+    }
+}
+// ----
+// TypeError: (101-115): Member "stateVar" not found or not visible after argument-dependent lookup in type(contract Scope)
diff --git a/test/libsolidity/syntaxTests/parsing/constant_state_modifier.sol b/test/libsolidity/syntaxTests/parsing/constant_state_modifier.sol
new file mode 100644
index 00000000..da068351
--- /dev/null
+++ b/test/libsolidity/syntaxTests/parsing/constant_state_modifier.sol
@@ -0,0 +1,7 @@
+contract C {
+	uint s;
+	// this test should fail starting from 0.5.0
+	function f() public constant returns (uint) {
+		return s;
+	}
+}
diff --git a/test/libsolidity/syntaxTests/parsing/empty_function.sol b/test/libsolidity/syntaxTests/parsing/empty_function.sol
index 4f845189..218fd9a7 100644
--- a/test/libsolidity/syntaxTests/parsing/empty_function.sol
+++ b/test/libsolidity/syntaxTests/parsing/empty_function.sol
@@ -1,10 +1,10 @@
 contract test {
 	uint256 stateVar;
-	function functionName(bytes20 arg1, address addr) constant returns (int id) { }
+	function functionName(bytes20 arg1, address addr) view returns (int id) { }
 }
 // ----
-// Warning: (36-115): No visibility specified. Defaulting to "public". 
+// Warning: (36-111): No visibility specified. Defaulting to "public". 
 // Warning: (58-70): Unused function parameter. Remove or comment out the variable name to silence this warning.
 // Warning: (72-84): Unused function parameter. Remove or comment out the variable name to silence this warning.
-// Warning: (104-110): Unused function parameter. Remove or comment out the variable name to silence this warning.
-// Warning: (36-115): Function state mutability can be restricted to pure
+// Warning: (100-106): Unused function parameter. Remove or comment out the variable name to silence this warning.
+// Warning: (36-111): Function state mutability can be restricted to pure
diff --git a/test/libsolidity/syntaxTests/parsing/multiple_statemutability_specifiers.sol b/test/libsolidity/syntaxTests/parsing/multiple_statemutability_specifiers.sol
new file mode 100644
index 00000000..a05bf452
--- /dev/null
+++ b/test/libsolidity/syntaxTests/parsing/multiple_statemutability_specifiers.sol
@@ -0,0 +1,33 @@
+contract c1 {
+    function f() payable payable {}
+}
+contract c2 {
+    function f() view view {}
+}
+contract c3 {
+    function f() pure pure {}
+}
+contract c4 {
+    function f() pure view {}
+}
+contract c5 {
+    function f() payable view {}
+}
+contract c6 {
+    function f() pure payable {}
+}
+contract c7 {
+    function f() pure constant {}
+}
+contract c8 {
+    function f() view constant {}
+}
+// ----
+// ParserError: (39-46): State mutability already specified as "payable".
+// ParserError: (88-92): State mutability already specified as "view".
+// ParserError: (134-138): State mutability already specified as "pure".
+// ParserError: (180-184): State mutability already specified as "pure".
+// ParserError: (229-233): State mutability already specified as "payable".
+// ParserError: (275-282): State mutability already specified as "pure".
+// ParserError: (324-332): State mutability already specified as "pure".
+// ParserError: (374-382): State mutability already specified as "view".