Introduced tuple type and added multi variable declarations to type

checker.

test/libsolidity/SolidityNameAndTypeResolution.cpp

@@ -1285,7 +1285,7 @@ BOOST_AUTO_TEST_CASE(empty_name_return_parameter_with_named_one)
 
 BOOST_AUTO_TEST_CASE(disallow_declaration_of_void_type)
 {
-	char const* sourceCode = "contract c { function f() { var x = f(); } }";
+	char const* sourceCode = "contract c { function f() { var (x) = f(); } }";
 	SOLIDITY_CHECK_ERROR_TYPE(parseAndAnalyseReturnError(sourceCode), TypeError);
 }
 
@@ -2134,7 +2134,7 @@ BOOST_AUTO_TEST_CASE(dynamic_return_types_not_possible)
 		contract C {
 			function f(uint) returns (string);
 			function g() {
-				var x = this.f(2);
+				var (x,) = this.f(2);
 			}
 		}
 	)";

test/libsolidity/SolidityParser.cpp

@@ -952,6 +952,18 @@ BOOST_AUTO_TEST_CASE(multi_variable_declaration)
 	BOOST_CHECK_NO_THROW(parseText(text));
 }
 
+BOOST_AUTO_TEST_CASE(multi_variable_declaration_invalid)
+{
+	char const* text = R"(
+		library Lib {
+			function f() {
+				var () = g();
+			}
+		}
+	)";
+	BOOST_CHECK_THROW(parseText(text), ParserError);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }