Merge pull request #3976 from ethereum/emptyTupleComponent

Empty tuple components should not be possible

test/libsolidity/syntaxTests/types/empty_tuple_event.sol

@@ -0,0 +1,10 @@
+pragma solidity ^0.4.3;
+contract C {
+    event SomeEvent();
+    function a() public {
+        (SomeEvent(), 7);
+    }
+}
+// ----
+// Warning: (95-106): Invoking events without "emit" prefix is deprecated.
+// Warning: (95-106): Tuple component cannot be empty.

test/libsolidity/syntaxTests/types/empty_tuple_event_050.sol

@@ -0,0 +1,10 @@
+pragma experimental "v0.5.0";
+contract C {
+    event SomeEvent();
+    function a() public {
+        (SomeEvent(), 7);
+    }
+}
+// ----
+// TypeError: (101-112): Event invocations have to be prefixed by "emit".
+// TypeError: (101-112): Tuple component cannot be empty.

test/libsolidity/syntaxTests/types/empty_tuple_function.sol

@@ -0,0 +1,12 @@
+pragma solidity ^0.4.3;
+contract C {
+    function f() private pure {}
+    function a() public pure {
+        bool x = true;
+        bool y = true;
+        (x) ? (f(), y = false) : (f(), y = false);
+    }
+}
+// ----
+// Warning: (162-165): Tuple component cannot be empty.
+// Warning: (181-184): Tuple component cannot be empty.

test/libsolidity/syntaxTests/types/empty_tuple_function_050.sol

@@ -0,0 +1,11 @@
+pragma experimental "v0.5.0";
+contract C {
+    function f() private pure {}
+    function a() public pure {
+        bool x = true;
+        bool y = true;
+        (x) ? (f(), y = false) : (f(), y = false);
+    }
+}
+// ----
+// TypeError: (168-171): Tuple component cannot be empty.

test/libsolidity/syntaxTests/types/empty_tuple_lvalue.sol

@@ -0,0 +1,13 @@
+pragma solidity ^0.4.3;
+contract C {
+    function f() private pure {}
+    function a() public {
+        uint x;
+        uint y;
+        (x, y) = (f(), f());
+    }
+}
+// ----
+// Warning: (146-149): Tuple component cannot be empty.
+// Warning: (151-154): Tuple component cannot be empty.
+// TypeError: (145-155): Type tuple(tuple(),tuple()) is not implicitly convertible to expected type tuple(uint256,uint256).

test/libsolidity/syntaxTests/types/empty_tuple_lvalue_050.sol

@@ -0,0 +1,11 @@
+pragma experimental "v0.5.0";
+contract C {
+    function f() private pure {}
+    function a() public {
+        uint x;
+        uint y;
+        (x, y) = (f(), f());
+    }
+}
+// ----
+// TypeError: (152-155): Tuple component cannot be empty.

test/libsolidity/syntaxTests/types/empty_tuple_lvalue_array.sol

@@ -0,0 +1,11 @@
+pragma solidity ^0.4.3;
+contract C {
+    function f() private pure {}
+    function a() public {
+        uint x;
+        uint y;
+        (x, y) = [f(), f()];
+    }
+}
+// ----
+// TypeError: (146-149): Array component cannot be empty.