8371382: [lworld] Javac accepts field initializer that refers to a superclass field

Reviewed-by: liach

Author: Vicente Romero

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

@@ -1258,7 +1258,8 @@ public void visitMethodDef(JCMethodDecl tree) {
                                         PrologueVisitorMode.WARNINGS_ONLY :
                                         thisInvocation ?
                                                 PrologueVisitorMode.THIS_CONSTRUCTOR :
-                                                PrologueVisitorMode.SUPER_CONSTRUCTOR);
+                                                PrologueVisitorMode.SUPER_CONSTRUCTOR,
+                                false);
                         ctorPrologueVisitor.scan(prologueCode.toList());
                     }
                 }
@@ -1282,11 +1283,13 @@ enum PrologueVisitorMode {
     class CtorPrologueVisitor extends TreeScanner {
         Env<AttrContext> localEnv;
         PrologueVisitorMode mode;
+        boolean isInitializer;
 
-        CtorPrologueVisitor(Env<AttrContext> localEnv, PrologueVisitorMode mode) {
+        CtorPrologueVisitor(Env<AttrContext> localEnv, PrologueVisitorMode mode, boolean isInitializer) {
             this.localEnv = localEnv;
             currentClassSym = localEnv.enclClass.sym;
             this.mode = mode;
+            this.isInitializer = isInitializer;
         }
 
         boolean insideLambdaOrClassDef = false;
@@ -1512,10 +1515,14 @@ void analyzeSymbol(JCTree tree) {
                     } else if (isEarlyReference(localEnv, tree, sym)) {
                         /* now this is a `proper` instance field of the current class
                          * references to fields of identity classes which happen to have initializers are
-                         * not allowed in the prologue
+                         * not allowed in the prologue.
+                         * But it is OK for a field with initializer to refer to another field with initializer,
+                         * so no warning or error if we are analyzing a field initializer.
                          */
                         if (insideLambdaOrClassDef ||
-                            (!localEnv.enclClass.sym.isValueClass() && (sym.flags_field & HASINIT) != 0))
+                            (!localEnv.enclClass.sym.isValueClass() &&
+                             (sym.flags_field & HASINIT) != 0 &&
+                             !isInitializer))
                             reportPrologueError(tree, sym);
                         // we will need to generate a proxy for this field later on
                         if (!isInLHS) {
@@ -1642,13 +1649,13 @@ public void visitVarDef(JCVariableDecl tree) {
             chk.checkDeprecatedAnnotation(tree.pos(), v);
 
             if (tree.init != null) {
+                Env<AttrContext> initEnv = memberEnter.initEnv(tree, env);
                 if ((v.flags_field & FINAL) == 0 ||
                     !memberEnter.needsLazyConstValue(tree.init)) {
                     // Not a compile-time constant
                     // Attribute initializer in a new environment
                     // with the declared variable as owner.
                     // Check that initializer conforms to variable's declared type.
-                    Env<AttrContext> initEnv = memberEnter.initEnv(tree, env);
                     initEnv.info.lint = lint;
                     // In order to catch self-references, we set the variable's
                     // declaration position to maximal possible value, effectively
@@ -1665,16 +1672,17 @@ public void visitVarDef(JCVariableDecl tree) {
                             //fixup local variable type
                             v.type = chk.checkLocalVarType(tree, tree.init.type, tree.name);
                         }
-                        if (allowValueClasses && v.owner.kind == TYP && !v.isStatic()) {
-                            // strict field initializers are inlined in constructor's prologues
-                            CtorPrologueVisitor ctorPrologueVisitor = new CtorPrologueVisitor(initEnv,
-                                    !v.isStrict() ? PrologueVisitorMode.WARNINGS_ONLY : PrologueVisitorMode.SUPER_CONSTRUCTOR);
-                            ctorPrologueVisitor.scan(tree.init);
-                        }
                     } finally {
                         initEnv.info.ctorPrologue = previousCtorPrologue;
                     }
                 }
+                if (allowValueClasses && v.owner.kind == TYP && !v.isStatic()) {
+                    // strict field initializers are inlined in constructor's prologues
+                    CtorPrologueVisitor ctorPrologueVisitor = new CtorPrologueVisitor(initEnv,
+                            !v.isStrict() ? PrologueVisitorMode.WARNINGS_ONLY : PrologueVisitorMode.SUPER_CONSTRUCTOR,
+                            true);
+                    ctorPrologueVisitor.scan(tree.init);
+                }
                 if (tree.isImplicitlyTyped()) {
                     setSyntheticVariableType(tree, v.type);
                 }

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

@@ -180,4 +180,9 @@ public static class Inner9 {
             super();
         }
     }
+
+    public static class Inner10 {
+        int x = 1;
+        int y = x + 1;  // no warning expected here
+    }
 }

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

@@ -7,9 +7,9 @@
  */
 import java.util.function.Function;
 abstract value class AR<V> implements java.io.Serializable {
+    int b = 5;
     public AR(V initialValue) {
     }
-
     public AR() {
     }
 }
@@ -178,4 +178,8 @@ public ValueClassSuperInitFails(int[][] z) {
     public ValueClassSuperInitFails(long[][] z) {
         super(new Inner1());            // this should FAIL
     }
+
+    // these two should FAIL
+    int a = b;
+    int aa = super.b;
 }

test/langtools/tools/javac/SuperInit/ValueClassSuperInitFails.out

@@ -14,6 +14,8 @@ ValueClassSuperInitFails.java:148:9: compiler.err.non.canonical.constructor.invo
 ValueClassSuperInitFails.java:161:46: compiler.err.cant.ref.before.ctor.called: hashCode()
 ValueClassSuperInitFails.java:175:49: compiler.err.cant.ref.before.ctor.called: x
 ValueClassSuperInitFails.java:179:15: compiler.err.cant.ref.before.ctor.called: ValueClassSuperInitFails
+ValueClassSuperInitFails.java:183:13: compiler.err.cant.ref.before.ctor.called: b
+ValueClassSuperInitFails.java:184:19: compiler.err.cant.ref.before.ctor.called: b
 ValueClassSuperInitFails.java:43:13: compiler.err.call.must.only.appear.in.ctor
 ValueClassSuperInitFails.java:47:14: compiler.err.call.must.only.appear.in.ctor
 ValueClassSuperInitFails.java:51:14: compiler.err.call.must.only.appear.in.ctor
@@ -25,4 +27,4 @@ ValueClassSuperInitFails.java:99:13: compiler.err.return.before.superclass.initi
 ValueClassSuperInitFails.java:170:18: compiler.err.call.must.only.appear.in.ctor
 - compiler.note.preview.filename: ValueClassSuperInitFails.java, DEFAULT
 - compiler.note.preview.recompile
-25 errors
+27 errors