Add ``staticcall`` to ``address``.

8 files changed, 116 insertions, 9 deletions

diff --git a/Changelog.md b/Changelog.md
index 177a071b..bef429b1 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -71,6 +71,7 @@ Breaking Changes:
  * View Pure Checker: Strictly enfore state mutability. This was already the case in the experimental 0.5.0 mode.
 
 Language Features:
+ * Genreal: Add ``staticcall`` to ``address``.
  * General: Allow appending ``calldata`` keyword to types, to explicitly specify data location for arguments of external functions.
  * General: Support ``pop()`` for storage arrays.
  * General: Scoping rules now follow the C99-style.
diff --git a/docs/units-and-global-variables.rst b/docs/units-and-global-variables.rst
index ceabee4e..a8086ddb 100644
--- a/docs/units-and-global-variables.rst
+++ b/docs/units-and-global-variables.rst
@@ -153,7 +153,7 @@ Mathematical and Cryptographic Functions
 
 It might be that you run into Out-of-Gas for ``sha256``, ``ripemd160`` or ``ecrecover`` on a *private blockchain*. The reason for this is that those are implemented as so-called precompiled contracts and these contracts only really exist after they received the first message (although their contract code is hardcoded). Messages to non-existing contracts are more expensive and thus the execution runs into an Out-of-Gas error. A workaround for this problem is to first send e.g. 1 Wei to each of the contracts before you use them in your actual contracts. This is not an issue on the official or test net.
 
-.. index:: balance, send, transfer, call, callcode, delegatecall
+.. index:: balance, send, transfer, call, callcode, delegatecall, staticcall
 .. _address_related:
 
 Address Related
@@ -171,6 +171,8 @@ Address Related
     issue low-level ``CALLCODE`` with the given payload, returns ``false`` on failure, forwards all available gas, adjustable
 ``<address>.delegatecall(bytes memory) returns (bool)``:
     issue low-level ``DELEGATECALL`` with the given payload, returns ``false`` on failure, forwards all available gas, adjustable
+``<address>.staticcall(bytes memory) returns (bool)``:
+    issue low-level ``STATICCALL`` with the given payload, returns ``false`` on failure, forwards all available gas, adjustable
 
 For more information, see the section on :ref:`address`.
 
diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index 43e894e5..8d6da28b 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -1359,7 +1359,8 @@ void TypeChecker::endVisit(ExpressionStatement const& _statement)
 			if (
 				kind == FunctionType::Kind::BareCall ||
 				kind == FunctionType::Kind::BareCallCode ||
-				kind == FunctionType::Kind::BareDelegateCall
+				kind == FunctionType::Kind::BareDelegateCall ||
+				kind == FunctionType::Kind::BareStaticCall
 			)
 				m_errorReporter.warning(_statement.location(), "Return value of low-level calls not used.");
 			else if (kind == FunctionType::Kind::Send)
@@ -1754,6 +1755,9 @@ bool TypeChecker::visit(FunctionCall const& _functionCall)
 		return false;
 	}
 
+	if (functionType->kind() == FunctionType::Kind::BareStaticCall && !m_evmVersion.hasStaticCall())
+		m_errorReporter.typeError(_functionCall.location(), "\"staticcall\" is not supported by the VM version.");
+
 	auto returnTypes =
 		allowDynamicTypes ?
 		functionType->returnParameterTypes() :
@@ -1834,7 +1838,8 @@ bool TypeChecker::visit(FunctionCall const& _functionCall)
 		else if (
 			functionType->kind() == FunctionType::Kind::BareCall ||
 			functionType->kind() == FunctionType::Kind::BareCallCode ||
-			functionType->kind() == FunctionType::Kind::BareDelegateCall
+			functionType->kind() == FunctionType::Kind::BareDelegateCall ||
+			functionType->kind() == FunctionType::Kind::BareStaticCall
 		)
 		{
 			if (arguments.empty())
@@ -1882,7 +1887,8 @@ bool TypeChecker::visit(FunctionCall const& _functionCall)
 				if (
 					functionType->kind() == FunctionType::Kind::BareCall ||
 					functionType->kind() == FunctionType::Kind::BareCallCode ||
-					functionType->kind() == FunctionType::Kind::BareDelegateCall
+					functionType->kind() == FunctionType::Kind::BareDelegateCall ||
+					functionType->kind() == FunctionType::Kind::BareStaticCall
 				)
 					msg += " This function requires a single bytes argument. If all your arguments are value types, you can use abi.encode(...) to properly generate it.";
 				else if (
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index c9dca126..ccf31543 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -621,6 +621,7 @@ MemberList::MemberMap IntegerType::nativeMembers(ContractDefinition const*) cons
 			{"callcode", make_shared<FunctionType>(strings{"bytes memory"}, strings{"bool"}, FunctionType::Kind::BareCallCode, false, StateMutability::Payable)},
 			{"delegatecall", make_shared<FunctionType>(strings{"bytes memory"}, strings{"bool"}, FunctionType::Kind::BareDelegateCall, false)},
 			{"send", make_shared<FunctionType>(strings{"uint"}, strings{"bool"}, FunctionType::Kind::Send)},
+			{"staticcall", make_shared<FunctionType>(strings{"bytes memory"}, strings{"bool"}, FunctionType::Kind::BareStaticCall, false, StateMutability::View)},
 			{"transfer", make_shared<FunctionType>(strings{"uint"}, strings(), FunctionType::Kind::Transfer)}
 		};
 	else
@@ -2522,6 +2523,7 @@ string FunctionType::richIdentifier() const
 	case Kind::BareCall: id += "barecall"; break;
 	case Kind::BareCallCode: id += "barecallcode"; break;
 	case Kind::BareDelegateCall: id += "baredelegatecall"; break;
+	case Kind::BareStaticCall: id += "barestaticcall"; break;
 	case Kind::Creation: id += "creation"; break;
 	case Kind::Send: id += "send"; break;
 	case Kind::Transfer: id += "transfer"; break;
@@ -2705,6 +2707,7 @@ unsigned FunctionType::sizeOnStack() const
 	case Kind::BareCall:
 	case Kind::BareCallCode:
 	case Kind::BareDelegateCall:
+	case Kind::BareStaticCall:
 	case Kind::Internal:
 	case Kind::ArrayPush:
 	case Kind::ArrayPop:
@@ -2772,6 +2775,7 @@ MemberList::MemberMap FunctionType::nativeMembers(ContractDefinition const*) con
 	case Kind::BareCall:
 	case Kind::BareCallCode:
 	case Kind::BareDelegateCall:
+	case Kind::BareStaticCall:
 	{
 		MemberList::MemberMap members;
 		if (m_kind == Kind::External)
@@ -2911,6 +2915,7 @@ bool FunctionType::isBareCall() const
 	case Kind::BareCall:
 	case Kind::BareCallCode:
 	case Kind::BareDelegateCall:
+	case Kind::BareStaticCall:
 	case Kind::ECRecover:
 	case Kind::SHA256:
 	case Kind::RIPEMD160:
@@ -3054,6 +3059,7 @@ bool FunctionType::padArguments() const
 	case Kind::BareCall:
 	case Kind::BareCallCode:
 	case Kind::BareDelegateCall:
+	case Kind::BareStaticCall:
 	case Kind::SHA256:
 	case Kind::RIPEMD160:
 	case Kind::KECCAK256:
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index d8e73ab9..0b1b5d6d 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -904,6 +904,7 @@ public:
 		BareCall, ///< CALL without function hash
 		BareCallCode, ///< CALLCODE without function hash
 		BareDelegateCall, ///< DELEGATECALL without function hash
+		BareStaticCall, ///< STATICCALL without function hash
 		Creation, ///< external call using CREATE
 		Send, ///< CALL, but without data and gas
 		Transfer, ///< CALL, but without data and throws on error
@@ -935,7 +936,7 @@ public:
 		ABIEncodeWithSelector,
 		ABIEncodeWithSignature,
 		ABIDecode,
-		GasLeft ///< gasleft()
+		GasLeft, ///< gasleft()
 	};
 
 	virtual Category category() const override { return Category::Function; }
@@ -1051,7 +1052,7 @@ public:
 	/// @returns true iff the function type is equal to the given type, ignoring state mutability differences.
 	bool equalExcludingStateMutability(FunctionType const& _other) const;
 
-	/// @returns true if the ABI is used for this call (only meaningful for external calls)
+	/// @returns true if the ABI is NOT used for this call (only meaningful for external calls)
 	bool isBareCall() const;
 	Kind const& kind() const { return m_kind; }
 	StateMutability stateMutability() const { return m_stateMutability; }
@@ -1090,6 +1091,7 @@ public:
 		case FunctionType::Kind::BareCall:
 		case FunctionType::Kind::BareCallCode:
 		case FunctionType::Kind::BareDelegateCall:
+		case FunctionType::Kind::BareStaticCall:
 			return true;
 		default:
 			return false;
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index 7a4548f5..9baad7d1 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -571,6 +571,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 		case FunctionType::Kind::BareCall:
 		case FunctionType::Kind::BareCallCode:
 		case FunctionType::Kind::BareDelegateCall:
+		case FunctionType::Kind::BareStaticCall:
 			_functionCall.expression().accept(*this);
 			appendExternalFunctionCall(function, arguments);
 			break;
@@ -1172,6 +1173,7 @@ bool ExpressionCompiler::visit(MemberAccess const& _memberAccess)
 				case FunctionType::Kind::BareCall:
 				case FunctionType::Kind::BareCallCode:
 				case FunctionType::Kind::BareDelegateCall:
+				case FunctionType::Kind::BareStaticCall:
 				case FunctionType::Kind::Transfer:
 					_memberAccess.expression().accept(*this);
 					m_context << funType->externalIdentifier();
@@ -1273,7 +1275,7 @@ bool ExpressionCompiler::visit(MemberAccess const& _memberAccess)
 			);
 			m_context << Instruction::BALANCE;
 		}
-		else if ((set<string>{"send", "transfer", "call", "callcode", "delegatecall"}).count(member))
+		else if ((set<string>{"send", "transfer", "call", "callcode", "delegatecall", "staticcall"}).count(member))
 			utils().convertType(
 				*_memberAccess.expression().annotation().type,
 				IntegerType(160, IntegerType::Modifier::Address),
@@ -1825,10 +1827,13 @@ void ExpressionCompiler::appendExternalFunctionCall(
 		utils().moveToStackTop(gasValueSize, _functionType.selfType()->sizeOnStack());
 
 	auto funKind = _functionType.kind();
-	bool returnSuccessCondition = funKind == FunctionType::Kind::BareCall || funKind == FunctionType::Kind::BareCallCode || funKind == FunctionType::Kind::BareDelegateCall;
+
+	solAssert(funKind != FunctionType::Kind::BareStaticCall || m_context.evmVersion().hasStaticCall(), "");
+	
+	bool returnSuccessCondition = funKind == FunctionType::Kind::BareCall || funKind == FunctionType::Kind::BareCallCode || funKind == FunctionType::Kind::BareDelegateCall || funKind == FunctionType::Kind::BareStaticCall;
 	bool isCallCode = funKind == FunctionType::Kind::BareCallCode || funKind == FunctionType::Kind::CallCode;
 	bool isDelegateCall = funKind == FunctionType::Kind::BareDelegateCall || funKind == FunctionType::Kind::DelegateCall;
-	bool useStaticCall = _functionType.stateMutability() <= StateMutability::View && m_context.evmVersion().hasStaticCall();
+	bool useStaticCall = funKind == FunctionType::Kind::BareStaticCall || (_functionType.stateMutability() <= StateMutability::View && m_context.evmVersion().hasStaticCall());
 
 	bool haveReturndatacopy = m_context.evmVersion().supportsReturndata();
 	unsigned retSize = 0;
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index 8a334e5e..b3618ad9 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -3592,6 +3592,19 @@ BOOST_AUTO_TEST_CASE(default_fallback_throws)
 	)YY";
 	compileAndRun(sourceCode);
 	ABI_CHECK(callContractFunction("f()"), encodeArgs(0));
+
+	if (dev::test::Options::get().evmVersion().hasStaticCall())
+	{
+		char const* sourceCode = R"YY(
+			contract A {
+				function f() public returns (bool) {
+					return address(this).staticcall("");
+				}
+			}
+		)YY";
+		compileAndRun(sourceCode);
+		ABI_CHECK(callContractFunction("f()"), encodeArgs(0));
+	}
 }
 
 BOOST_AUTO_TEST_CASE(short_data_calls_fallback)
@@ -4215,6 +4228,49 @@ BOOST_AUTO_TEST_CASE(generic_delegatecall)
 	BOOST_CHECK_EQUAL(balanceAt(c_senderAddress), 50 + 11);
 }
 
+BOOST_AUTO_TEST_CASE(generic_staticcall)
+{
+	if (dev::test::Options::get().evmVersion().hasStaticCall())
+	{
+		char const* sourceCode = R"**(
+				contract A {
+					uint public x;
+					constructor() public { x = 42; }
+					function pureFunction(uint256 p) public pure returns (uint256) { return p; }
+					function viewFunction(uint256 p) public view returns (uint256) { return p + x; }
+					function nonpayableFunction(uint256 p) public returns (uint256) { x = p; return x; }
+					function assertFunction(uint256 p) public view returns (uint256) { assert(x == p); return x; }
+				}
+				contract C {
+					function f(address a) public view returns (bool)
+					{
+						return a.staticcall(abi.encodeWithSignature("pureFunction(uint256)", 23));
+					}
+					function g(address a) public view returns (bool)
+					{
+						return a.staticcall(abi.encodeWithSignature("viewFunction(uint256)", 23));
+					}
+					function h(address a) public view returns (bool)
+					{
+						return a.staticcall(abi.encodeWithSignature("nonpayableFunction(uint256)", 23));
+					}
+					function i(address a, uint256 v) public view returns (bool)
+					{
+						return a.staticcall(abi.encodeWithSignature("assertFunction(uint256)", v));
+					}
+				}
+		)**";
+		compileAndRun(sourceCode, 0, "A");
+		u160 const c_addressA = m_contractAddress;
+		compileAndRun(sourceCode, 0, "C");
+		ABI_CHECK(callContractFunction("f(address)", c_addressA), encodeArgs(true));
+		ABI_CHECK(callContractFunction("g(address)", c_addressA), encodeArgs(true));
+		ABI_CHECK(callContractFunction("h(address)", c_addressA), encodeArgs(false));
+		ABI_CHECK(callContractFunction("i(address,uint256)", c_addressA, 42), encodeArgs(true));
+		ABI_CHECK(callContractFunction("i(address,uint256)", c_addressA, 23), encodeArgs(false));
+	}
+}
+
 BOOST_AUTO_TEST_CASE(library_call_in_homestead)
 {
 	char const* sourceCode = R"(
@@ -12216,6 +12272,19 @@ BOOST_AUTO_TEST_CASE(bare_call_invalid_address)
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f()"), encodeArgs(u256(1)));
 	ABI_CHECK(callContractFunction("h()"), encodeArgs(u256(1)));
+
+	if (dev::test::Options::get().evmVersion().hasStaticCall())
+	{
+		char const* sourceCode = R"YY(
+			contract C {
+				function f() external returns (bool) {
+					return address(0x4242).staticcall("");
+				}
+			}
+		)YY";
+		compileAndRun(sourceCode, 0, "C");
+		ABI_CHECK(callContractFunction("f()"), encodeArgs(u256(1)));
+	}
 }
 
 BOOST_AUTO_TEST_CASE(delegatecall_return_value)
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index 55e81867..fbb2f09c 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -433,6 +433,22 @@ BOOST_AUTO_TEST_CASE(getter_is_memory_type)
 	}
 }
 
+BOOST_AUTO_TEST_CASE(address_staticcall)
+{
+	char const* sourceCode = R"(
+		contract C {
+			function f() public view returns(bool) {
+				return address(0x4242).staticcall("");
+			}
+		}
+	)";
+
+	if (dev::test::Options::get().evmVersion().hasStaticCall())
+		CHECK_SUCCESS_NO_WARNINGS(sourceCode);
+	else
+		CHECK_ERROR(sourceCode, TypeError, "\"staticcall\" is not supported by the VM version.");
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }