Fix three more bugs related to st

5 files changed, 64 insertions, 2 deletions

diff --git a/output/ex20.java b/output/ex20.java
new file mode 100644
index 0000000..87dca29
--- /dev/null
+++ b/output/ex20.java
@@ -0,0 +1,22 @@
+class ex20 {
+    public static void main(String[] a){
+        System.out.println(new A().start());
+    }
+}
+
+class C extends B{
+}
+
+class B extends A{
+}
+
+class A{
+
+    A a;
+    C c;
+
+    public int start(){
+        a = c;
+        return 0;
+    }
+}
diff --git a/output/ex21.java b/output/ex21.java
new file mode 100644
index 0000000..2bb11a3
--- /dev/null
+++ b/output/ex21.java
@@ -0,0 +1,24 @@
+class test66{
+    public static void main(String[] a){
+        System.out.println(new Test().start());
+    }
+}
+
+class Test2 extends Test{
+}
+
+class Test{
+
+    Test test;
+
+    public int start(){
+        test = test.next();
+        return 0;
+    }
+
+    public Test next() {
+        Test2 test2;
+        test2 = new Test2();
+        return test2;
+    }
+}
diff --git a/output/negative/ExtendMissing.java b/output/negative/ExtendMissing.java
new file mode 100644
index 0000000..72a487a
--- /dev/null
+++ b/output/negative/ExtendMissing.java
@@ -0,0 +1,12 @@
+class ExtendMissing {
+    public static void main(String[] a){
+	System.out.println(new Test().start());
+    }
+}
+
+class Test extends NotPresent {  //TE
+
+    public int start(){
+	return 0;
+    }
+}
diff --git a/st/ClassInstance.java b/st/ClassInstance.java
index a7a4500..3de852f 100644
--- a/st/ClassInstance.java
+++ b/st/ClassInstance.java
@@ -39,8 +39,8 @@ public class ClassInstance extends AbstractInstance {
         }
 
         ClassInstance te = this.getExtend();
-        if (te.equals(o)) {
-            MinimalLogger.info(String.format("I (%s) extends %s!", this.getName(), o.getName()));
+        if (te.equalsOnExtend(o)) {
+            MinimalLogger.info(String.format("I (%s) extend %s!", this.getName(), o.getName()));
             return true;
         }
         MinimalLogger.info(String.format("I (%s) do not extend %s! I extend %s instead.", this.getName(), o.getName(), te.getName()));
diff --git a/st/SymbolTable.java b/st/SymbolTable.java
index 0fca239..fa196e3 100644
--- a/st/SymbolTable.java
+++ b/st/SymbolTable.java
@@ -52,6 +52,10 @@ public class SymbolTable {
         ClassInstance cls = (ClassInstance) this.active.get(TypeEnum.classname);
         ClassInstance ext = this.getClass(arg);
 
+        if (ext == null)
+            throw new TypecheckException(String.format("There is no %s to extend!",
+                                                       arg));
+
         MinimalLogger.info(String.format("%s found to extend %s",
                                          cls.getName(),
                                          ext.getName()));