Merge pull request #4431 from ethereum/tupleDeclaration

Disallow multi variable declarations with mismatching number of values.

22 files changed, 177 insertions, 103 deletions

diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index ad425d98..bee83007 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -8091,17 +8091,36 @@ BOOST_AUTO_TEST_CASE(multi_variable_declaration)
 			function g() public returns (uint a, uint b, uint c) {
 				a = 1; b = 2; c = 3;
 			}
-			function f() public returns (bool) {
+			function h() public returns (uint a, uint b, uint c, uint d) {
+				a = 1; b = 2; c = 3; d = 4;
+			}
+			function f1() public returns (bool) {
 				(uint x, uint y, uint z) = g();
 				if (x != 1 || y != 2 || z != 3) return false;
 				(, uint a,) = g();
 				if (a != 2) return false;
-				(uint b,) = g();
+				(uint b, , ) = g();
 				if (b != 1) return false;
-				(, uint c) = g();
+				(, , uint c) = g();
 				if (c != 3) return false;
 				return true;
 			}
+			function f2() public returns (bool) {
+				(uint a1, , uint a3, ) = h();
+				if (a1 != 1 || a3 != 3) return false;
+				(uint b1, uint b2, , ) = h();
+				if (b1 != 1 || b2 != 2) return false;
+				(, uint c2, uint c3, ) = h();
+				if (c2 != 2 || c3 != 3) return false;
+				(, , uint d3, uint d4) = h();
+				if (d3 != 3 || d4 != 4) return false;
+				(uint e1, , uint e3, uint e4) = h();
+				if (e1 != 1 || e3 != 3 || e4 != 4) return false;
+				return true;
+			}
+			function f() public returns (bool) {
+				return f1() && f2();
+			}
 		}
 	)";
 	compileAndRun(sourceCode);
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/differentNumberOfComponents.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/differentNumberOfComponents.sol
new file mode 100644
index 00000000..3b05a54c
--- /dev/null
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/differentNumberOfComponents.sol
@@ -0,0 +1,25 @@
+contract C {
+    function f() public {
+        uint a = (1,2);
+        uint b = (1,2,3);
+        uint c = (1,2,3,4);
+    }
+    function g() public {
+        (uint a1, uint b1, uint c1, uint d1) = 1;
+        (uint a2, uint b2, uint c2) = 1;
+        (uint a3, uint b3) = 1;
+    }
+    function h() public {
+        (uint a1, uint b1, uint c1, uint d1) = (1,2,3);
+        (uint a2, uint b2, uint c2) = (1,2,3,4);
+    }
+}
+// ----
+// TypeError: (47-61): Different number of components on the left hand side (1) than on the right hand side (2).
+// TypeError: (71-87): Different number of components on the left hand side (1) than on the right hand side (3).
+// TypeError: (97-115): Different number of components on the left hand side (1) than on the right hand side (4).
+// TypeError: (157-197): Different number of components on the left hand side (4) than on the right hand side (1).
+// TypeError: (207-238): Different number of components on the left hand side (3) than on the right hand side (1).
+// TypeError: (248-270): Different number of components on the left hand side (2) than on the right hand side (1).
+// TypeError: (312-358): Different number of components on the left hand side (4) than on the right hand side (3).
+// TypeError: (368-407): Different number of components on the left hand side (3) than on the right hand side (4).
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/differentNumberOfComponentsFromReturn.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/differentNumberOfComponentsFromReturn.sol
new file mode 100644
index 00000000..7b556350
--- /dev/null
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/differentNumberOfComponentsFromReturn.sol
@@ -0,0 +1,29 @@
+contract C {
+    function f() public {
+        uint a = two();
+        uint b = three();
+        uint c = four();
+    }
+    function g() public {
+        (uint a1, uint b1, uint c1, uint d1) = one();
+        (uint a2, uint b2, uint c2) = one();
+        (uint a3, uint b3) = one();
+    }
+    function h() public {
+        (uint a1, uint b1, uint c1, uint d1) = three();
+        (uint a2, uint b2, uint c2) = four();
+    }
+    function one() public pure returns (uint);
+    function two() public pure returns (uint, uint);
+    function three() public pure returns (uint, uint, uint);
+    function four() public pure returns (uint, uint, uint, uint);
+}
+// ----
+// TypeError: (47-61): Different number of components on the left hand side (1) than on the right hand side (2).
+// TypeError: (71-87): Different number of components on the left hand side (1) than on the right hand side (3).
+// TypeError: (97-112): Different number of components on the left hand side (1) than on the right hand side (4).
+// TypeError: (154-198): Different number of components on the left hand side (4) than on the right hand side (1).
+// TypeError: (208-243): Different number of components on the left hand side (3) than on the right hand side (1).
+// TypeError: (253-279): Different number of components on the left hand side (2) than on the right hand side (1).
+// TypeError: (321-367): Different number of components on the left hand side (4) than on the right hand side (3).
+// TypeError: (377-413): Different number of components on the left hand side (3) than on the right hand side (4).
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/disallowWildcards.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/disallowWildcards.sol
new file mode 100644
index 00000000..b500823d
--- /dev/null
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/disallowWildcards.sol
@@ -0,0 +1,24 @@
+contract C {
+    function fn() public pure {
+        (uint a,) = (1,2,3);
+        (,uint b) = (1,2,3);
+        (,uint c,) = (1,2,3,4,5);
+        (uint d, uint e,) = (1,2,3,4);
+        (,uint f, uint g) = (1,2,3,4);
+        (,uint h, uint i,) = (1,2,3);
+        (uint j,) = 1;
+        (,uint k) = 1;
+        (,uint l,) = 1;
+        a;b;c;d;e;f;g;h;i;j;k;l;
+    }
+}
+// ----
+// TypeError: (53-72): Different number of components on the left hand side (2) than on the right hand side (3).
+// TypeError: (82-101): Different number of components on the left hand side (2) than on the right hand side (3).
+// TypeError: (111-135): Different number of components on the left hand side (3) than on the right hand side (5).
+// TypeError: (145-174): Different number of components on the left hand side (3) than on the right hand side (4).
+// TypeError: (184-213): Different number of components on the left hand side (3) than on the right hand side (4).
+// TypeError: (223-251): Different number of components on the left hand side (4) than on the right hand side (3).
+// TypeError: (261-274): Different number of components on the left hand side (2) than on the right hand side (1).
+// TypeError: (284-297): Different number of components on the left hand side (2) than on the right hand side (1).
+// TypeError: (307-321): Different number of components on the left hand side (3) than on the right hand side (1).
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/disallowWildcardsFromReturn.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/disallowWildcardsFromReturn.sol
new file mode 100644
index 00000000..3224a182
--- /dev/null
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/disallowWildcardsFromReturn.sol
@@ -0,0 +1,31 @@
+contract C {
+    function fn() public pure {
+        (uint a,) = three();
+        (,uint b) = three();
+        (,uint c,) = five();
+        (uint d, uint e,) = four();
+        (,uint f, uint g) = four();
+        (,uint h, uint i,) = three();
+        (uint j,) = one();
+        (,uint k) = one();
+        (,uint l,) = one();
+        (,uint m, uint n,) = five();
+        a;b;c;d;e;f;g;h;i;j;k;l;m;n;
+    }
+    function one() public pure returns (uint);
+    function two() public pure returns (uint, uint);
+    function three() public pure returns (uint, uint, uint);
+    function four() public pure returns (uint, uint, uint, uint);
+    function five() public pure returns (uint, uint, uint, uint, uint);
+}
+// ----
+// TypeError: (53-72): Different number of components on the left hand side (2) than on the right hand side (3).
+// TypeError: (82-101): Different number of components on the left hand side (2) than on the right hand side (3).
+// TypeError: (111-130): Different number of components on the left hand side (3) than on the right hand side (5).
+// TypeError: (140-166): Different number of components on the left hand side (3) than on the right hand side (4).
+// TypeError: (176-202): Different number of components on the left hand side (3) than on the right hand side (4).
+// TypeError: (212-240): Different number of components on the left hand side (4) than on the right hand side (3).
+// TypeError: (250-267): Different number of components on the left hand side (2) than on the right hand side (1).
+// TypeError: (277-294): Different number of components on the left hand side (2) than on the right hand side (1).
+// TypeError: (304-322): Different number of components on the left hand side (3) than on the right hand side (1).
+// TypeError: (332-359): Different number of components on the left hand side (4) than on the right hand side (5).
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationComplex.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationComplex.sol
index a3ce6a74..ba6e9916 100644
--- a/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationComplex.sol
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationComplex.sol
@@ -2,10 +2,10 @@ contract D {
   struct S { uint a; uint b; }
 }
 contract C {
-  function f() internal returns (uint, uint, uint, D.S[20] storage, uint) {
-    (,,,D.S[10*2] storage x,) = f();
+  function f() internal pure {
+    (,,,D.S[10*2] storage x,) = g();
     x;
   }
-} 
+  function g() internal pure returns (uint, uint, uint, D.S[20] storage x, uint) { x = x; }
+}
 // ----
-// Warning: (110-117): This variable is of storage pointer type and might be returned without assignment. This can cause storage corruption. Assign the variable (potentially from itself) to remove this warning.
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationEmpty.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationEmpty.sol
new file mode 100644
index 00000000..9618958e
--- /dev/null
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationEmpty.sol
@@ -0,0 +1,11 @@
+contract C {
+    function f() public pure {
+        (uint a, uint b) = f();
+        (uint c) = f();
+        uint d = f();
+    }
+}
+// ----
+// TypeError: (52-74): Different number of components on the left hand side (2) than on the right hand side (0).
+// TypeError: (84-98): Different number of components on the left hand side (1) than on the right hand side (0).
+// TypeError: (108-120): Different number of components on the left hand side (1) than on the right hand side (0).
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationSimple.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationSimple.sol
index 8e06322c..a2fcce18 100644
--- a/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationSimple.sol
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationSimple.sol
@@ -1,12 +1,12 @@
 contract C {
-  function f() internal returns (uint, uint, uint, uint) {
+  function f() internal pure returns (uint, uint, uint, uint) {
     (uint a, uint b,,) = f();
     a; b;
   }
-  function g() internal returns (bytes memory, string storage) {
-    (bytes memory a, string storage b) = g();
+  function g() internal pure {
+    (bytes memory a, string storage b) = h();
     a; b;
   }
-} 
+  function h() internal pure returns (bytes memory, string storage s) { s = s; }
+}
 // ----
-// Warning: (163-169): This variable is of storage pointer type and might be returned without assignment. This can cause storage corruption. Assign the variable (potentially from itself) to remove this warning.
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/oneElementTuple.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/oneElementTuple.sol
new file mode 100644
index 00000000..562c7c0b
--- /dev/null
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/oneElementTuple.sol
@@ -0,0 +1,8 @@
+contract C {
+    function f() public {
+        (uint a,) = (1,);
+        a;
+    }
+}
+// ----
+// TypeError: (59-63): Tuple component cannot be empty.
diff --git a/test/libsolidity/syntaxTests/multiVariableDeclaration/sameNumberOfComponents.sol b/test/libsolidity/syntaxTests/multiVariableDeclaration/sameNumberOfComponents.sol
new file mode 100644
index 00000000..59eb34af
--- /dev/null
+++ b/test/libsolidity/syntaxTests/multiVariableDeclaration/sameNumberOfComponents.sol
@@ -0,0 +1,9 @@
+contract C {
+    function f() public pure {
+        (uint a1, uint b1, uint c1, uint d1) = (1,2,3,4);
+        (uint a2, uint b2, uint c2) = (1,2,3);
+        (uint a3, uint b3) = (1,2);
+        a1; b1; c1; d1; a2; b2; c2; a3; b3;
+    }
+}
+// ----
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/239_multi_variable_declaration_wildcards_fine.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/239_multi_variable_declaration_wildcards_fine.sol
deleted file mode 100644
index f3afd0cc..00000000
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/239_multi_variable_declaration_wildcards_fine.sol
+++ /dev/null
@@ -1,21 +0,0 @@
-contract C {
-    function three() public returns (uint, uint, uint);
-    function two() public returns (uint, uint);
-    function none() public;
-    function f() public {
-        (uint a,) = three();
-        (uint b, uint c,) = two();
-        (,uint d) = three();
-        (,uint e, uint g) = two();
-        var (,,) = three();
-        var () = none();
-        a;b;c;d;e;g;
-    }
-}
-// ----
-// SyntaxError: (307-325): The use of the "var" keyword is disallowed. The declaration part of the statement can be removed, since it is empty.
-// SyntaxError: (335-350): The use of the "var" keyword is disallowed. The declaration part of the statement can be removed, since it is empty.
-// Warning: (179-198): Different number of components on the left hand side (2) than on the right hand side (3).
-// Warning: (208-233): Different number of components on the left hand side (3) than on the right hand side (2).
-// Warning: (243-262): Different number of components on the left hand side (2) than on the right hand side (3).
-// Warning: (272-297): Different number of components on the left hand side (3) than on the right hand side (2).
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/240_multi_variable_declaration_wildcards_fail_1.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/240_multi_variable_declaration_wildcards_fail_1.sol
deleted file mode 100644
index 0ccbb327..00000000
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/240_multi_variable_declaration_wildcards_fail_1.sol
+++ /dev/null
@@ -1,7 +0,0 @@
-contract C {
-    function one() public returns (uint);
-    function f() public { (uint a, uint b, ) = one(); }
-}
-// ----
-// Warning: (81-107): Different number of components on the left hand side (3) than on the right hand side (1).
-// TypeError: (81-107): Not enough components (1) in value to assign all variables (2).
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/241_multi_variable_declaration_wildcards_fail_2.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/241_multi_variable_declaration_wildcards_fail_2.sol
deleted file mode 100644
index 8d5de125..00000000
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/241_multi_variable_declaration_wildcards_fail_2.sol
+++ /dev/null
@@ -1,7 +0,0 @@
-contract C {
-    function one() public returns (uint);
-    function f() public { (uint a, , ) = one(); }
-}
-// ----
-// Warning: (81-101): Different number of components on the left hand side (3) than on the right hand side (1).
-// TypeError: (81-101): Not enough components (1) in value to assign all variables (2).
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/242_multi_variable_declaration_wildcards_fail_3.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/242_multi_variable_declaration_wildcards_fail_3.sol
deleted file mode 100644
index 993df9b9..00000000
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/242_multi_variable_declaration_wildcards_fail_3.sol
+++ /dev/null
@@ -1,7 +0,0 @@
-contract C {
-    function one() public returns (uint);
-    function f() public { (, , uint a) = one(); }
-}
-// ----
-// Warning: (81-101): Different number of components on the left hand side (3) than on the right hand side (1).
-// TypeError: (81-101): Not enough components (1) in value to assign all variables (2).
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/243_multi_variable_declaration_wildcards_fail_4.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/243_multi_variable_declaration_wildcards_fail_4.sol
deleted file mode 100644
index 0697b789..00000000
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/243_multi_variable_declaration_wildcards_fail_4.sol
+++ /dev/null
@@ -1,7 +0,0 @@
-contract C {
-    function one() public returns (uint);
-    function f() public { (, uint a, uint b) = one(); }
-}
-// ----
-// Warning: (81-107): Different number of components on the left hand side (3) than on the right hand side (1).
-// TypeError: (81-107): Not enough components (1) in value to assign all variables (2).
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/244_tuples.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/244_tuples.sol
index 95e8cf37..d18c115d 100644
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/244_tuples.sol
+++ b/test/libsolidity/syntaxTests/nameAndTypeResolution/244_tuples.sol
@@ -1,13 +1,10 @@
 contract C {
-    function f() public {
+    function f() public pure {
         uint a = (1);
-        (uint b,) = uint8(1);
+        (uint b,) = (uint8(1),2);
         (uint c, uint d) = (uint32(1), 2 + a);
-        (uint e,) = (uint64(1), 2, b);
+        (uint e, ,) = (uint64(1), 2, b);
         a;b;c;d;e;
     }
 }
 // ----
-// Warning: (69-89): Different number of components on the left hand side (2) than on the right hand side (1).
-// Warning: (146-175): Different number of components on the left hand side (2) than on the right hand side (3).
-// Warning: (17-201): Function state mutability can be restricted to pure
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/246_multi_variable_declaration_wildcards_fail_5.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/246_multi_variable_declaration_wildcards_fail_5.sol
deleted file mode 100644
index 3599a342..00000000
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/246_multi_variable_declaration_wildcards_fail_5.sol
+++ /dev/null
@@ -1,7 +0,0 @@
-contract C {
-    function one() public returns (uint);
-    function f() public { var (,) = one(); }
-}
-// ----
-// SyntaxError: (81-96): The use of the "var" keyword is disallowed. The declaration part of the statement can be removed, since it is empty.
-// TypeError: (81-96): Wildcard both at beginning and end of variable declaration list is only allowed if the number of components is equal.
diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/247_multi_variable_declaration_wildcards_fail_6.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/247_multi_variable_declaration_wildcards_fail_6.sol
deleted file mode 100644
index cc5953db..00000000
--- a/test/libsolidity/syntaxTests/nameAndTypeResolution/247_multi_variable_declaration_wildcards_fail_6.sol
+++ /dev/null
@@ -1,7 +0,0 @@
-contract C {
-    function two() public returns (uint, uint);
-    function f() public { (uint a, uint b, uint c) = two(); }
-}
-// ----
-// Warning: (87-119): Different number of components on the left hand side (3) than on the right hand side (2).
-// TypeError: (87-119): Not enough components (2) in value to assign all variables (3).
diff --git a/test/libsolidity/syntaxTests/parsing/multi_variable_declarations.sol b/test/libsolidity/syntaxTests/parsing/multi_variable_declarations.sol
index 1984ed36..56c2e280 100644
--- a/test/libsolidity/syntaxTests/parsing/multi_variable_declarations.sol
+++ b/test/libsolidity/syntaxTests/parsing/multi_variable_declarations.sol
@@ -2,8 +2,8 @@ contract C {
 	function f() pure public {
 		(uint a, uint b, uint c) = g();
 		(uint d) = 2;
-		(, uint e) = 3;
-		(uint h,) = 4;
+		(, uint e) = (3,4);
+		(uint h,) = (4,5);
 		(uint x,,) = g();
 		(, uint y,) = g();
         a; b; c; d; e; h; x; y;
@@ -11,5 +11,3 @@ contract C {
 	function g() pure public returns (uint, uint, uint) {}
 }
 // ----
-// Warning: (93-107): Different number of components on the left hand side (2) than on the right hand side (1).
-// Warning: (111-124): Different number of components on the left hand side (2) than on the right hand side (1).
diff --git a/test/libsolidity/syntaxTests/parsing/tuples.sol b/test/libsolidity/syntaxTests/parsing/tuples.sol
index ca2f9d6b..875556e9 100644
--- a/test/libsolidity/syntaxTests/parsing/tuples.sol
+++ b/test/libsolidity/syntaxTests/parsing/tuples.sol
@@ -1,16 +1,11 @@
 contract C {
-	function f() public {
+	function f() public pure {
 		uint a = (1);
-		(uint b,) = 1;
+		(uint b,) = (1,2);
 		(uint c, uint d) = (1, 2 + a);
-		(uint e,) = (1, 2, b);
+		(uint e,) = (1, b);
 		(a) = 3;
+		a;b;c;d;e;
 	}
 }
 // ----
-// Warning: (54-67): Different number of components on the left hand side (2) than on the right hand side (1).
-// Warning: (104-125): Different number of components on the left hand side (2) than on the right hand side (3).
-// Warning: (72-78): Unused local variable.
-// Warning: (80-86): Unused local variable.
-// Warning: (105-111): Unused local variable.
-// Warning: (14-140): Function state mutability can be restricted to pure
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_vardecl.sol b/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_vardecl.sol
deleted file mode 100644
index 23484567..00000000
--- a/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_vardecl.sol
+++ /dev/null
@@ -1,8 +0,0 @@
-contract C {
-	function f() public pure returns (uint, uint, uint, uint) {
-		(uint a, uint b,) = f();
-		a; b;
-	}
-}
-// ----
-// Warning: (76-99): Different number of components on the left hand side (3) than on the right hand side (4).
diff --git a/test/libsolidity/syntaxTests/types/unnamed_tuple_decl.sol b/test/libsolidity/syntaxTests/types/unnamed_tuple_decl.sol
index 6c1489f5..7ed92b58 100644
--- a/test/libsolidity/syntaxTests/types/unnamed_tuple_decl.sol
+++ b/test/libsolidity/syntaxTests/types/unnamed_tuple_decl.sol
@@ -16,4 +16,3 @@ contract C {
 // SyntaxError: (249-261): The use of the "var" keyword is disallowed. The declaration part of the statement can be removed, since it is empty.
 // SyntaxError: (271-283): The use of the "var" keyword is disallowed. The declaration part of the statement can be removed, since it is empty.
 // SyntaxError: (293-306): The use of the "var" keyword is disallowed. The declaration part of the statement can be removed, since it is empty.
-// TypeError: (271-283): Too many components (1) in value for variable assignment (0) needed