Fix #4505

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/internal/DataflowPass.java

@@ -36,6 +36,7 @@ import net.sourceforge.pmd.lang.java.ast.ASTConstructorCall;
 import net.sourceforge.pmd.lang.java.ast.ASTConstructorDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTContinueStatement;
 import net.sourceforge.pmd.lang.java.ast.ASTDoStatement;
+import net.sourceforge.pmd.lang.java.ast.ASTEnumConstant;
 import net.sourceforge.pmd.lang.java.ast.ASTExpression;
 import net.sourceforge.pmd.lang.java.ast.ASTFieldAccess;
 import net.sourceforge.pmd.lang.java.ast.ASTFieldDeclaration;
@@ -954,6 +955,7 @@ public final class DataflowPass {
 
         @Override
         public SpanInfo visitTypeDecl(ASTAnyTypeDeclaration node, SpanInfo data) {
+            // process initializers and ctors first
             processInitializers(node.getDeclarations(), data, node.getSymbol());
 
             for (ASTBodyDeclaration decl : node.getDeclarations()) {
@@ -989,12 +991,14 @@ public final class DataflowPass {
 
             for (ASTBodyDeclaration declaration : declarations) {
                 final boolean isStatic;
-                if (declaration instanceof ASTFieldDeclaration) {
+                if (declaration instanceof ASTEnumConstant) {
+                    isStatic = true;
+                } else if (declaration instanceof ASTFieldDeclaration) {
                     isStatic = ((ASTFieldDeclaration) declaration).isStatic();
                 } else if (declaration instanceof ASTInitializer) {
                     isStatic = ((ASTInitializer) declaration).isStatic();
                 } else if (declaration instanceof ASTConstructorDeclaration
-                        || declaration instanceof ASTCompactConstructorDeclaration) {
+                    || declaration instanceof ASTCompactConstructorDeclaration) {
                     ctors.add(declaration);
                     continue;
                 } else {

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/ImplicitSwitchFallThrough.xml

@@ -400,4 +400,25 @@ record MyRecord(boolean b) {
 }
         ]]></code>
     </test-code>
+
+    <test-code>
+        <description>NPE with Switch in enum constant body</description>
+        <expected-problems>1</expected-problems>
+        <expected-linenumbers>7</expected-linenumbers>
+        <code><![CDATA[
+            enum Foo {
+                A {
+                    void foo() {
+                        switch (A) {
+                        case A:
+                            if (A != null) {}
+                        default:
+                            throw new UnsupportedOperationException();
+                        }
+                    }
+                }
+            }
+
+            ]]></code>
+    </test-code>
 </test-data>