Add more test cases for the compiler, we rule!!!

svn path=/trunk/mcs/; revision=405

mcs/errors/cs0146.cs

@@ -0,0 +1,7 @@
+// cs0146.cs: circular class definition
+// Line: 6
+class A : B {
+}
+
+class B : A {
+}

mcs/errors/cs0246.cs

@@ -0,0 +1,4 @@
+// cs0246.cs: can not find type `B'
+// Line: 4
+interface A : B {
+}

mcs/errors/cs0509.cs

@@ -0,0 +1,8 @@
+// cs0509.cs: base class is sealed
+// Line: 7
+struct V {
+	int v;
+}
+
+class X : V {
+}

mcs/errors/cs0527-2.cs

@@ -0,0 +1,8 @@
+class A1 {
+}
+
+class A2 {
+}
+
+class B : A1, A2 {
+}

mcs/errors/cs0527.cs

@@ -0,0 +1,7 @@
+// cs0527:  type in interface list is not an interface
+// Line: 6
+class X {
+}
+
+interface A : X {
+}

mcs/errors/cs0529.cs

@@ -0,0 +1,7 @@
+// cs0529: Recursive interface definition
+// Line: 3
+interface A : B {
+}
+
+interface B : A {
+}