8328649: Disallow enclosing instances for local classes in constructor prologues

Reviewed-by: vromero

Author: archiecobbs

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

@@ -954,10 +954,10 @@ public void visitClassDef(JCClassDecl tree) {
                 // make sure class has been completed:
                 c.complete();
 
-                // If this class appears as an anonymous class in a constructor
-                // prologue, disable implicit outer instance from being passed.
-                // (This would be an illegal access to "this before super").
-                if (ctorProloguePrev && env.tree.hasTag(NEWCLASS)) {
+                // If a class declaration appears in a constructor prologue,
+                // that means it's either a local class or an anonymous class.
+                // Either way, there is no immediately enclosing instance.
+                if (ctorProloguePrev) {
                     c.flags_field |= NOOUTERTHIS;
                 }
                 attribClass(tree.pos(), c);

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

@@ -1843,7 +1843,6 @@ JCExpression makeOuterThis(DiagnosticPosition pos, TypeSymbol c) {
         List<VarSymbol> ots = outerThisStack;
         if (ots.isEmpty()) {
             log.error(pos, Errors.NoEnclInstanceOfTypeInScope(c));
-            Assert.error();
             return makeNull();
         }
         VarSymbol ot = ots.head;

test/langtools/tools/javac/LocalClassCtorPrologue.java

@@ -0,0 +1,32 @@
+/*
+ * @test  /nodynamiccopyright/
+ * @bug 8328649
+ * @summary Verify local classes in constructor prologues don't have enclosing instances
+ * @compile/fail/ref=LocalClassCtorPrologue.out -XDrawDiagnostics LocalClassCtorPrologue.java
+ * @enablePreview
+ */
+
+class LocalClassCtorPrologue {
+
+    int x;
+
+    LocalClassCtorPrologue() {
+        class Local {
+            {
+                x++;                // this should fail
+            }
+        }
+        super();
+    }
+
+    public class Inner {
+        public Inner() {
+            class Local {
+                {
+                    x++;            // this should work
+                }
+            };
+            super();
+        }
+    }
+}

test/langtools/tools/javac/LocalClassCtorPrologue.out

@@ -0,0 +1,4 @@
+LocalClassCtorPrologue.java:16:17: compiler.err.no.encl.instance.of.type.in.scope: LocalClassCtorPrologue
+- compiler.note.preview.filename: LocalClassCtorPrologue.java, DEFAULT
+- compiler.note.preview.recompile
+1 error

test/langtools/tools/javac/SuperInit/SuperInitGood.java

@@ -407,32 +407,6 @@ public int hashCode() {
         }
     }
 
-    // local class declared before super(), but not used until after super()
-    public static class Test20 {
-        public Test20() {
-            class Foo {
-                Foo() {
-                    Test20.this.hashCode();
-                }
-            }
-            super();
-            new Foo();
-        }
-    }
-
-    // local class inside super() parameter list
-    public static class Test21 extends AtomicReference<Object> {
-        private int x;
-        public Test21() {
-            super(switch ("foo".hashCode()) {
-                default -> {
-                    class Nested {{ System.out.println(x); }}       // class is NOT instantiated - OK
-                    yield "bar";
-                }
-            });
-        }
-    }
-
     public static void main(String[] args) {
         new Test0();
         new Test1();
@@ -474,7 +448,5 @@ public static void main(String[] args) {
             assert false : "unexpected exception: " + e;
         }
         new Test19(123);
-        new Test20();
-        new Test21();
     }
 }