8320220: Compilation of cyclic hierarchy causes infinite recursion

Reviewed-by: vromero, jlahoda

Author: archiecobbs

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Check.java

@@ -2374,7 +2374,12 @@ void checkClass(DiagnosticPosition pos, Symbol c, List<JCTree> supertypes) {
                 return;
             if (seenClasses.contains(c)) {
                 errorFound = true;
-                noteCyclic(pos, (ClassSymbol)c);
+                log.error(pos, Errors.CyclicInheritance(c));
+                seenClasses.stream()
+                  .filter(s -> !s.type.isErroneous())
+                  .filter(ClassSymbol.class::isInstance)
+                  .map(ClassSymbol.class::cast)
+                  .forEach(Check.this::handleCyclic);
             } else if (!c.type.isErroneous()) {
                 try {
                     seenClasses.add(c);
@@ -2451,7 +2456,8 @@ private boolean checkNonCyclicInternal(DiagnosticPosition pos, Type t) {
         if ((c.flags_field & ACYCLIC) != 0) return true;
 
         if ((c.flags_field & LOCKED) != 0) {
-            noteCyclic(pos, (ClassSymbol)c);
+            log.error(pos, Errors.CyclicInheritance(c));
+            handleCyclic((ClassSymbol)c);
         } else if (!c.type.isErroneous()) {
             try {
                 c.flags_field |= LOCKED;
@@ -2478,9 +2484,10 @@ private boolean checkNonCyclicInternal(DiagnosticPosition pos, Type t) {
         return complete;
     }
 
-    /** Note that we found an inheritance cycle. */
-    private void noteCyclic(DiagnosticPosition pos, ClassSymbol c) {
-        log.error(pos, Errors.CyclicInheritance(c));
+    /** Handle finding an inheritance cycle on a class by setting
+     *  the class' and its supertypes' types to the error type.
+     **/
+    private void handleCyclic(ClassSymbol c) {
         for (List<Type> l=types.interfaces(c.type); l.nonEmpty(); l=l.tail)
             l.head = types.createErrorType((ClassSymbol)l.head.tsym, Type.noType);
         Type st = types.supertype(c.type);

test/langtools/tools/javac/ClassCycle/ClassCycle4.java

@@ -0,0 +1,10 @@
+/*
+ * @test /nodynamiccopyright/
+ * @bug 8320220
+ * @summary Fix infinite recursion in cyclic inheritance situation
+ * @compile/fail/ref=ClassCycle4.out -XDrawDiagnostics ClassCycle4.java
+ */
+
+interface ClassCycle4 extends I1, I2 {}
+interface I1 extends ClassCycle4 {}
+interface I2 extends ClassCycle4 {}

test/langtools/tools/javac/ClassCycle/ClassCycle4.out

@@ -0,0 +1,2 @@
+ClassCycle4.java:8:1: compiler.err.cyclic.inheritance: ClassCycle4
+1 error