Fix Class literals in field access and related type checks

checker/jtreg/nullness/EISOPissue548/ConservativeClassLiteral.java

@@ -0,0 +1,15 @@
+/*
+ * @test
+ * @summary Test class literals in CFGs and their type with conservative nullness.
+ *
+ * @compile MyEnum.java
+ * @compile -processor org.checkerframework.checker.nullness.NullnessChecker -AuseConservativeDefaultsForUncheckedCode=bytecode,-source ConservativeClassLiteral.java
+ */
+
+import java.util.EnumSet;
+
+class ConservativeClassLiteral {
+    EnumSet<MyEnum> none() {
+        return EnumSet.noneOf(MyEnum.class);
+    }
+}

checker/jtreg/nullness/EISOPissue548/MyEnum.java

@@ -0,0 +1,3 @@
+enum MyEnum {
+    VALUE;
+}

checker/src/main/java/org/checkerframework/checker/initialization/InitializationParentAnnotatedTypeFactory.java

@@ -793,6 +793,10 @@ public Void visitNewArray(NewArrayTree tree, AnnotatedTypeMirror type) {
         @Override
         public Void visitMemberSelect(
                 MemberSelectTree tree, AnnotatedTypeMirror annotatedTypeMirror) {
+            Element elt = TreeUtils.elementFromUse(tree);
+            if (elt.toString().equals("class")) {
+                annotatedTypeMirror.replaceAnnotation(INITIALIZED);
+            }
             if (TreeUtils.isArrayLengthAccess(tree)) {
                 annotatedTypeMirror.replaceAnnotation(INITIALIZED);
             }

checker/src/main/java/org/checkerframework/checker/nullness/NullnessNoInitAnnotatedTypeFactory.java

@@ -673,6 +673,9 @@ public Void visitMemberSelect(MemberSelectTree tree, AnnotatedTypeMirror type) {
                 type.replaceAnnotation(NONNULL);
             }
 
+            if (elt.toString().equals("class")) {
+                type.replaceAnnotation(NONNULL);
+            }
             return null;
         }
 

dataflow/src/main/java/org/checkerframework/dataflow/cfg/builder/CFGTranslationPhaseOne.java

@@ -3663,7 +3663,7 @@ public Node visitMemberSelect(MemberSelectTree tree, Void p) {
         if (!TreeUtils.isFieldAccess(tree)) {
             // Could be a selector of a class or package
             Element element = TreeUtils.elementFromUse(tree);
-            if (ElementUtils.isTypeElement(element)) {
+            if (ElementUtils.isTypeElement(element) || element.toString().equals("class")) {
                 ClassNameNode result = new ClassNameNode(tree, expr);
                 extendWithClassNameNode(result);
                 return result;

dataflow/src/main/java/org/checkerframework/dataflow/cfg/node/ClassNameNode.java

@@ -63,7 +63,9 @@ public ClassNameNode(MemberSelectTree tree, Node parent) {
         this.tree = tree;
         assert TreeUtils.isUseOfElement(tree) : "@AssumeAssertion(nullness): tree kind";
         Element element = TreeUtils.elementFromUse(tree);
-        assert element instanceof TypeElement || element instanceof TypeParameterElement
+        assert element instanceof TypeElement
+                        || element instanceof TypeParameterElement
+                        || element.toString().equals("class")
                 : "@AssumeAssertion(nullness)";
         this.element = element;
         this.parent = parent;

javacutil/src/main/java/org/checkerframework/javacutil/TreeUtils.java

@@ -1467,7 +1467,7 @@ public static boolean isFieldAccess(Tree tree) {
             MemberSelectTree memberSelect = (MemberSelectTree) tree;
             assert isUseOfElement(memberSelect) : "@AssumeAssertion(nullness): tree kind";
             Element el = TreeUtils.elementFromUse(memberSelect);
-            if (el.getKind().isField()) {
+            if (el.getKind().isField() && !el.toString().equals("class")) {
                 return (VariableElement) el;
             }
         } else if (tree.getKind() == Tree.Kind.IDENTIFIER) {