Add tests for multi variable declaration statement.

test/libsolidity/SolidityEndToEndTest.cpp

@@ -7610,6 +7610,33 @@ BOOST_AUTO_TEST_CASE(multi_variable_declaration)
 	ABI_CHECK(callContractFunction("f()", encodeArgs()), encodeArgs(true));
 }
 
+BOOST_AUTO_TEST_CASE(typed_multi_variable_declaration)
+{
+	char const* sourceCode = R"(
+		contract C {
+			struct S { uint x; }
+			S s;
+			function g() internal returns (uint, S storage, uint) {
+				s.x = 7;
+				return (1, s, 2);
+			}
+			function f() returns (bool) {
+				(uint x1, S storage y1, uint z1) = g();
+				if (x1 != 1 || y1.x != 7 || z1 != 2) return false;
+				(, S storage y2,) = g();
+				if (y2.x != 7) return false;
+				(uint x2,,) = g();
+				if (x2 != 1) return false;
+				(,,uint z2) = g();
+				if (z2 != 2) return false;
+				return true;
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+	ABI_CHECK(callContractFunction("f()", encodeArgs()), encodeArgs(true));
+}
+
 BOOST_AUTO_TEST_CASE(tuples)
 {
 	char const* sourceCode = R"(

test/libsolidity/syntaxTests/multiVariableDeclaration/multiSingleVariableDeclaration.sol

@@ -0,0 +1,6 @@
+contract C {
+  function f() internal returns (uint) {
+    (uint a) = f();
+    a;
+  }
+} 

test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationComplex.sol

@@ -0,0 +1,11 @@
+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();
+    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.

test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationInvalid.sol

@@ -0,0 +1,8 @@
+contract C {
+  function f() internal returns (uint, uint, uint, uint) {
+    var (uint a, uint b,,) = f();
+    a; b;
+  }
+} 
+// ----
+// ParserError: (81-85): Expected identifier but got 'uint'

test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationInvalidType.sol

@@ -0,0 +1,9 @@
+contract C {
+  function f() internal returns (string memory, uint, uint, uint) {
+    (uint a, string memory b,,) = f();
+    a; b;
+  }
+} 
+// ----
+// TypeError: (85-118): Type string memory is not implicitly convertible to expected type uint256.
+// TypeError: (85-118): Type uint256 is not implicitly convertible to expected type string memory.

test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationScoping.sol

@@ -0,0 +1,12 @@
+pragma experimental "v0.5.0";
+
+contract C {
+  function f() internal {
+    {
+      (uint a, uint b, uint c) = (1, 2, 3);
+    }
+    a;
+  }
+} 
+// ----
+// DeclarationError: (130-131): Undeclared identifier.

test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationScoping2.sol

@@ -0,0 +1,13 @@
+pragma experimental "v0.5.0";
+
+contract C {
+  function f() internal {
+    {
+      (uint a, uint b, uint c) = (a, b, c);
+    }
+  }
+} 
+// ----
+// DeclarationError: (110-111): Undeclared identifier. Did you mean "a"?
+// DeclarationError: (113-114): Undeclared identifier. Did you mean "b"?
+// DeclarationError: (116-117): Undeclared identifier. Did you mean "c"?

test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationSimple.sol

@@ -0,0 +1,12 @@
+contract C {
+  function f() internal 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();
+    a; b;
+  }
+} 
+// ----
+// 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.

test/libsolidity/syntaxTests/multiVariableDeclaration/multiVariableDeclarationThatIsExpression.sol

@@ -0,0 +1,9 @@
+contract C {
+  struct S { function() returns (S storage)[] x; }
+  S s;
+  function f() internal pure returns (uint, uint, uint, S storage, uint, uint) {
+    (,,,s.x[2](),,) = f();
+  }
+} 
+// ----
+// TypeError: (160-168): Expression has to be an lvalue.