Merge branch 'semantic/edge_cases' into 'master'

Group 5: Additional semantic test cases

See merge request !39

semantic/adding_booleans.invalid.mj

+class Foo {
+
+    public static void main(String[] args) {
+        boolean bar = true + false;
+    }
+}

semantic/binary_operations_on_int.invalid.mj

+class Foo {
+
+    public static void main(String[] args) {
+        if(1 && 0) {
+            System.out.println(42);
+        }
+    }
+}

semantic/main_access_args.invalid.mj

+class Foo {
+    public static void main(String[] args) {
+        args[0] = null;
+    }    
+}

semantic/main_wrong_type_args.invalid.mj

+class Foo {
+    public static void main(int[] args) {} 
+}

semantic/same_method_name_different_classes.mj

+class Foo {
+    public void bar() {}
+    public static void main(String[] args) {
+        (new Foo()).bar();
+        (new Bar()).bar();
+    }
+}
+class Bar {
+    public void bar() {}
+}

semantic/system_shadowing_wrong_parameter_type.invalid.mj

+
+class SystemShadowing {
+    public SystemShadowing System;
+    public SystemShadowing  out;
+
+    public void println(boolean x) { }
+
+    public void nonstatic() {
+        System.out.println(42);
+    }
+
+    public static void main(String[] args) {
+        SystemShadowing x = new SystemShadowing();
+        x.nonstatic();
+    }
+}