[SMTChecker] Support this as address

test/libsolidity/smtCheckerTests/functions/function_call_does_not_clear_local_vars.sol

@@ -9,5 +9,4 @@ contract C {
     }
 }
 // ----
-// Warning: (99-103): Assertion checker does not yet support the type of this variable.
 // Warning: (141-144): Assertion checker does not support recursive function calls.

test/libsolidity/smtCheckerTests/special/this.sol

@@ -0,0 +1,10 @@
+pragma experimental SMTChecker;
+
+contract C
+{
+	function f(address a) public view {
+		assert(a == address(this));
+	}
+}
+// ----
+// Warning: (85-111): Assertion violation happens here

test/libsolidity/smtCheckerTests/special/this_state.sol

@@ -0,0 +1,11 @@
+pragma experimental SMTChecker;
+
+contract C
+{
+	address thisAddr;
+	function f(address a) public {
+		require(a == address(this));
+		thisAddr = a;
+		assert(thisAddr == address(this));
+	}
+}