Merge pull request #3643 from ethereum/gasleft

Move msg.gas to global function gasleft(). Closes #2971.

4 files changed, 90 insertions, 0 deletions

diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index c352a2c2..ebb2f3ff 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -5352,6 +5352,18 @@ BOOST_AUTO_TEST_CASE(super_overload)
 	ABI_CHECK(callContractFunction("h()"), encodeArgs(2));
 }
 
+BOOST_AUTO_TEST_CASE(gasleft_shadow_resolution)
+{
+	char const* sourceCode = R"(
+		contract C {
+			function gasleft() returns(uint256) { return 0; }
+			function f() returns(uint256) { return gasleft(); }
+		}
+	)";
+	compileAndRun(sourceCode, 0, "C");
+	ABI_CHECK(callContractFunction("f()"), encodeArgs(0));
+}
+
 BOOST_AUTO_TEST_CASE(bool_conversion)
 {
 	char const* sourceCode = R"(
diff --git a/test/libsolidity/SolidityExpressionCompiler.cpp b/test/libsolidity/SolidityExpressionCompiler.cpp
index 44d3daff..5f044b44 100644
--- a/test/libsolidity/SolidityExpressionCompiler.cpp
+++ b/test/libsolidity/SolidityExpressionCompiler.cpp
@@ -515,6 +515,39 @@ BOOST_AUTO_TEST_CASE(blockhash)
 	BOOST_CHECK_EQUAL_COLLECTIONS(code.begin(), code.end(), expectation.begin(), expectation.end());
 }
 
+BOOST_AUTO_TEST_CASE(gas_left)
+{
+	char const* sourceCode = R"(
+		contract test {
+			function f() returns (uint256 val) {
+				return msg.gas;
+			}
+		}
+	)";
+	bytes code = compileFirstExpression(
+		sourceCode, {}, {},
+		{make_shared<MagicVariableDeclaration>("msg", make_shared<MagicType>(MagicType::Kind::Message))}
+	);
+
+	bytes expectation({byte(Instruction::GAS)});
+	BOOST_CHECK_EQUAL_COLLECTIONS(code.begin(), code.end(), expectation.begin(), expectation.end());
+
+	sourceCode = R"(
+		contract test {
+			function f() returns (uint256 val) {
+				return gasleft();
+			}
+		}
+	)";
+	code = compileFirstExpression(
+		sourceCode, {}, {},
+		{make_shared<MagicVariableDeclaration>("gasleft", make_shared<FunctionType>(strings(), strings{"uint256"}, FunctionType::Kind::GasLeft))}
+	);
+
+	expectation = bytes({byte(Instruction::GAS)});
+	BOOST_CHECK_EQUAL_COLLECTIONS(code.begin(), code.end(), expectation.begin(), expectation.end());
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index e503c22b..7b0a7d4c 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -7410,6 +7410,50 @@ BOOST_AUTO_TEST_CASE(builtin_reject_gas)
 	CHECK_ERROR(text, TypeError, "Member \"gas\" not found or not visible after argument-dependent lookup");
 }
 
+BOOST_AUTO_TEST_CASE(gasleft)
+{
+	char const* text = R"(
+		contract C {
+			function f() public view returns (uint256 val) { return msg.gas; }
+		}
+	)";
+	CHECK_SUCCESS_NO_WARNINGS(text);
+
+	text = R"(
+		contract C {
+			function f() public view returns (uint256 val) { return gasleft(); }
+		}
+	)";
+	CHECK_SUCCESS_NO_WARNINGS(text);
+
+	text = R"(
+		pragma experimental "v0.5.0";
+		contract C {
+			function f() public returns (uint256 val) { return msg.gas; }
+		}
+	)";
+	CHECK_ERROR(text, TypeError, "Member \"gas\" not found or not visible after argument-dependent lookup in msg");
+}
+
+BOOST_AUTO_TEST_CASE(gasleft_shadowing)
+{
+	char const* text = R"(
+		contract C {
+			function gasleft() public pure returns (bytes32 val) { return "abc"; }
+			function f() public pure returns (bytes32 val) { return gasleft(); }
+		}
+	)";
+	CHECK_WARNING(text, "This declaration shadows a builtin symbol.");
+
+	text = R"(
+		contract C {
+			uint gasleft;
+			function f() public { gasleft = 42; }
+		}
+	)";
+	CHECK_WARNING(text, "This declaration shadows a builtin symbol.");
+}
+
 BOOST_AUTO_TEST_CASE(builtin_reject_value)
 {
 	char const* text = R"(
diff --git a/test/libsolidity/ViewPureChecker.cpp b/test/libsolidity/ViewPureChecker.cpp
index e6a5cfd0..ed4cf792 100644
--- a/test/libsolidity/ViewPureChecker.cpp
+++ b/test/libsolidity/ViewPureChecker.cpp
@@ -111,6 +111,7 @@ BOOST_AUTO_TEST_CASE(environment_access)
 		"block.difficulty",
 		"block.number",
 		"block.gaslimit",
+		"gasleft()",
 		"msg.gas",
 		"msg.value",
 		"msg.sender",