8027375: javac asserts on nested erroneous annotations

Summary: make sure JCAnnotation trees have type != null before annotation processing
Reviewed-by: jjg

src/share/classes/com/sun/tools/javac/comp/Annotate.java

@@ -255,6 +255,9 @@ public class Annotate {
                   : attr.attribType(a.annotationType, env));
         a.type = chk.checkType(a.annotationType.pos(), at, expected);
         if (a.type.isErroneous()) {
+            // Need to make sure nested (anno)trees does not have null as .type
+            attr.postAttr(a);
+
             if (typeAnnotation) {
                 return new Attribute.TypeCompound(a.type, List.<Pair<MethodSymbol,Attribute>>nil(),
                         new TypeAnnotationPosition());
@@ -265,6 +268,10 @@ public class Annotate {
         if ((a.type.tsym.flags() & Flags.ANNOTATION) == 0) {
             log.error(a.annotationType.pos(),
                       "not.annotation.type", a.type.toString());
+
+            // Need to make sure nested (anno)trees does not have null as .type
+            attr.postAttr(a);
+
             if (typeAnnotation) {
                 return new Attribute.TypeCompound(a.type, List.<Pair<MethodSymbol,Attribute>>nil(), null);
             } else {
@@ -278,7 +285,7 @@ public class Annotate {
                 Assign(make.Ident(names.value), args.head);
         }
         ListBuffer<Pair<MethodSymbol,Attribute>> buf =
-            new ListBuffer<Pair<MethodSymbol,Attribute>>();
+            new ListBuffer<>();
         for (List<JCExpression> tl = args; tl.nonEmpty(); tl = tl.tail) {
             JCExpression t = tl.head;
             if (!t.hasTag(ASSIGN)) {
@@ -304,8 +311,7 @@ public class Annotate {
             Type result = method.type.getReturnType();
             Attribute value = enterAttributeValue(result, assign.rhs, env);
             if (!method.type.isErroneous())
-                buf.append(new Pair<MethodSymbol,Attribute>
-                           ((MethodSymbol)method, value));
+                buf.append(new Pair<>((MethodSymbol)method, value));
             t.type = result;
         }
         if (typeAnnotation) {

test/tools/javac/annotations/testCrashNestedAnnos/TestCrashNestedAnnos.java

+/* @test /nodynamiccopyright/
+ * @bug 8027375
+ * @summary Test that javac doesn't assert/crash when there are what looks to
+ *          be annotations nested inside erroneous annotations.
+ * @compile/fail/ref=TestCrashNestedAnnos.out -XDrawDiagnostics TestCrashNestedAnnos.java
+ */
+public class TestCrashNestedAnnos {
+    // A and B are not annotation types
+    @A(@A1()) int foo() {}
+    @B(@B1()) int bar() {}
+}
+
+class B {}
+class B1 {}

test/tools/javac/annotations/testCrashNestedAnnos/TestCrashNestedAnnos.out

+TestCrashNestedAnnos.java:9:6: compiler.err.cant.resolve.location: kindname.class, A, , , (compiler.misc.location: kindname.class, TestCrashNestedAnnos, null)
+TestCrashNestedAnnos.java:10:6: compiler.err.prob.found.req: (compiler.misc.inconvertible.types: B, java.lang.annotation.Annotation)
+2 errors