[SMTChecker] Support inheritance and resolve overrides

test/libsolidity/smtCheckerTests/inheritance/functions_1.sol

@@ -0,0 +1,25 @@
+pragma experimental SMTChecker;
+
+// 2 warnings, A.f and A.g
+contract A {
+	uint x;
+
+	function f() public view {
+		assert(x == 1);
+	}
+	function g() public view {
+		assert(x == 1);
+	}
+}
+
+// 2 warnings, B.f and A.g
+contract B is A {
+	function f() public view {
+		assert(x == 0);
+	}
+}
+// ----
+// Warning: (113-127): Assertion violation happens here
+// Warning: (162-176): Assertion violation happens here
+// Warning: (259-273): Assertion violation happens here
+// Warning: (162-176): Assertion violation happens here

test/libsolidity/smtCheckerTests/inheritance/functions_2.sol

@@ -0,0 +1,27 @@
+pragma experimental SMTChecker;
+
+// 2 warnings, A.f and A.g
+contract A {
+	uint x;
+
+	function f() public view {
+		assert(x == 1);
+	}
+	function g() public view {
+		assert(x == 1);
+	}
+}
+
+// 2 warnings, B.f and A.g
+contract B is A {
+	uint y;
+
+	function f() public view {
+		assert(x == 0);
+	}
+}
+// ----
+// Warning: (113-127): Assertion violation happens here
+// Warning: (162-176): Assertion violation happens here
+// Warning: (269-283): Assertion violation happens here
+// Warning: (162-176): Assertion violation happens here

test/libsolidity/smtCheckerTests/inheritance/functions_3.sol

@@ -0,0 +1,47 @@
+pragma experimental SMTChecker;
+
+// 2 warnings, A.f and A.g
+contract A {
+	uint x;
+
+	function f() public view {
+		assert(x == 1);
+	}
+	function g() public view {
+		assert(x == 1);
+	}
+}
+
+// 3 warnings, B.f, B.h, A.g
+contract B is A {
+	uint y;
+
+	function f() public view {
+		assert(x == 0);
+	}
+	function h() public view {
+		assert(x == 2);
+	}
+}
+
+// 4 warnings, C.f, C.i, B.h, A.g
+contract C is B {
+	uint z;
+
+	function f() public view {
+		assert(x == 0);
+	}
+	function i() public view {
+		assert(x == 0);
+	}
+}
+// ----
+// Warning: (113-127): Assertion violation happens here
+// Warning: (162-176): Assertion violation happens here
+// Warning: (271-285): Assertion violation happens here
+// Warning: (320-334): Assertion violation happens here
+// Warning: (162-176): Assertion violation happens here
+// Warning: (434-448): Assertion violation happens here
+// Warning: (483-497): Assertion violation happens here
+// Warning: (320-334): Assertion violation happens here
+// Warning: (162-176): Assertion violation happens here