Merge pull request #9536 from dotty-staging/fix-annot-cycle

Fix #9492: Avoid forcing nested annotation

Author: odersky

compiler/src/dotty/tools/dotc/core/Annotations.scala

@@ -163,12 +163,6 @@ object Annotations {
         protected var myTree: Tree | (Context ?=> Tree) = (using ctx) => treeFn(using ctx)
       }
 
-    def deferred(atp: Type, args: List[Tree])(using Context): Annotation =
-      deferred(atp.classSymbol)(New(atp, args))
-
-    def deferredResolve(atp: Type, args: List[ast.untpd.Tree])(using Context): Annotation =
-      deferred(atp.classSymbol)(ast.untpd.resolveConstructor(atp, args))
-
     /** Extractor for child annotations */
     object Child {
 

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -555,14 +555,25 @@ class ClassfileParser(
           Some(untpd.JavaSeqLiteral(elems, TypeTree()))
         }
       case ANNOTATION_TAG =>
-        parseAnnotation(index, skip) map (_.tree)
+        parseAnnotation(index, skip).map(_.untpdTree)
     }
   }
 
+  class ClassfileAnnotation(annotType: Type, args: List[untpd.Tree]) extends LazyAnnotation {
+    protected var mySym: Symbol | (Context ?=> Symbol) =
+      (using ctx: Context) => annotType.classSymbol
+
+    protected var myTree: Tree | (Context ?=> Tree) =
+      (using ctx: Context) => untpd.resolveConstructor(annotType, args)
+
+    def untpdTree(using Context): untpd.Tree =
+      untpd.New(untpd.TypeTree(annotType), List(args))
+  }
+
   /** Parse and return a single annotation.  If it is malformed,
    *  return None.
    */
-  def parseAnnotation(attrNameIndex: Char, skip: Boolean = false)(using Context): Option[Annotation] = try {
+  def parseAnnotation(attrNameIndex: Char, skip: Boolean = false)(using Context): Option[ClassfileAnnotation] = try {
     val attrType = pool.getType(attrNameIndex)
     attrType match
       case tp: TypeRef =>
@@ -584,7 +595,7 @@ class ClassfileParser(
       }
     }
     if (hasError || skip) None
-    else Some(Annotation.deferredResolve(attrType, argbuf.toList))
+    else Some(ClassfileAnnotation(attrType, argbuf.toList))
   }
   catch {
     case f: FatalError => throw f // don't eat fatal errors, they mean a class was not found

tests/pos-java-interop-separate/i9492/A_1.java

@@ -0,0 +1,15 @@
+import java.lang.annotation.*;
+
+@interface BaseClassAnn {
+    Type[] value();
+    @interface Type {
+        Class<?> value();
+    }
+}
+
+@BaseClassAnn({
+    @BaseClassAnn.Type(value=A_1.class)
+})
+abstract class BaseClass {}
+
+public class A_1 extends BaseClass {}

tests/pos-java-interop-separate/i9492/B_2.scala

@@ -0,0 +1,3 @@
+object Test {
+  def oops: A_1 = ???
+}