Fix handling of arrays in java annotation arguments

compiler/src/dotty/tools/dotc/ast/Trees.scala

@@ -4,6 +4,7 @@ package ast
 
 import core._
 import Types._, Names._, NameOps._, Flags._, util.Spans._, Contexts._, Constants._
+import typer.ProtoTypes
 import SymDenotations._, Symbols._, Denotations._, StdNames._, Comments._
 import language.higherKinds
 import collection.mutable.ListBuffer
@@ -1505,5 +1506,58 @@ object Trees {
         case tree: TypeDef => cpy.TypeDef(tree)(name = newName.asTypeName)
       }
     }.asInstanceOf[tree.ThisTree[T]]
+
+    /** Delegate to FunProto or FunProtoTyped depending on whether the prefix is `untpd` or `tpd`. */
+    protected def FunProto(args: List[Tree], resType: Type)(using Context): ProtoTypes.FunProto
+
+    /** Construct the application `$receiver.$method[$targs]($args)` using overloading resolution
+     *  to find a matching overload of `$method` if necessary.
+     *  This is useful when overloading resolution needs to be performed in a phase after typer.
+     *  Note that this will not perform any kind of implicit search.
+     *
+     *  @param expectedType  An expected type of the application used to guide overloading resolution
+     */
+    def applyOverloaded(
+        receiver: tpd.Tree, method: TermName, args: List[Tree], targs: List[Type],
+        expectedType: Type)(using parentCtx: Context): tpd.Tree = {
+      given ctx as Context = parentCtx.retractMode(Mode.ImplicitsEnabled)
+
+      val typer = ctx.typer
+      val proto = FunProto(args, expectedType)
+      val denot = receiver.tpe.member(method)
+      assert(denot.exists, i"no member $receiver . $method, members = ${receiver.tpe.decls}")
+      val selected =
+        if (denot.isOverloaded) {
+          def typeParamCount(tp: Type) = tp.widen match {
+            case tp: PolyType => tp.paramInfos.length
+            case _ => 0
+          }
+          val allAlts = denot.alternatives
+            .map(denot => TermRef(receiver.tpe, denot.symbol))
+            .filter(tr => typeParamCount(tr) == targs.length)
+            .filter { _.widen match {
+              case MethodTpe(_, _, x: MethodType) => !x.isImplicitMethod
+              case _ => true
+            }}
+          val alternatives = ctx.typer.resolveOverloaded(allAlts, proto)
+          assert(alternatives.size == 1,
+            i"${if (alternatives.isEmpty) "no" else "multiple"} overloads available for " +
+              i"$method on ${receiver.tpe.widenDealiasKeepAnnots} with targs: $targs%, %; args: $args%, %; expectedType: $expectedType." +
+              i"all alternatives: ${allAlts.map(_.symbol.showDcl).mkString(", ")}\n" +
+              i"matching alternatives: ${alternatives.map(_.symbol.showDcl).mkString(", ")}.") // this is parsed from bytecode tree. there's nothing user can do about it
+            alternatives.head
+        }
+        else TermRef(receiver.tpe, denot.symbol)
+      val fun = receiver.select(selected).appliedToTypes(targs)
+
+      val apply = untpd.Apply(fun, args)
+      typer.ApplyTo(apply, fun, selected, proto, expectedType)
+    }
+
+
+    def resolveConstructor(atp: Type, args: List[Tree])(implicit ctx: Context): tpd.Tree = {
+      val targs = atp.argTypes
+      applyOverloaded(tpd.New(atp.typeConstructor), nme.CONSTRUCTOR, args, targs, atp)
+    }
   }
 }

compiler/src/dotty/tools/dotc/ast/tpd.scala

@@ -3,7 +3,7 @@ package dotc
 package ast
 
 import dotty.tools.dotc.transform.{ExplicitOuter, Erasure}
-import dotty.tools.dotc.typer.ProtoTypes.FunProtoTyped
+import typer.ProtoTypes
 import transform.SymUtils._
 import transform.TypeUtils._
 import core._
@@ -1152,41 +1152,6 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     }
   }
 
-  def applyOverloaded(receiver: Tree, method: TermName, args: List[Tree], targs: List[Type],
-                      expectedType: Type, isContextual: Boolean = false)(implicit ctx: Context): Tree = {
-    val typer = ctx.typer
-    val proto = FunProtoTyped(args, expectedType)(typer, isContextual)
-    val denot = receiver.tpe.member(method)
-    assert(denot.exists, i"no member $receiver . $method, members = ${receiver.tpe.decls}")
-    val selected =
-      if (denot.isOverloaded) {
-        def typeParamCount(tp: Type) = tp.widen match {
-          case tp: PolyType => tp.paramInfos.length
-          case _ => 0
-        }
-        var allAlts = denot.alternatives
-          .map(denot => TermRef(receiver.tpe, denot.symbol))
-          .filter(tr => typeParamCount(tr) == targs.length)
-          .filter { _.widen match {
-            case MethodTpe(_, _, x: MethodType) => !x.isImplicitMethod
-            case _ => true
-          }}
-        if (targs.isEmpty) allAlts = allAlts.filterNot(_.widen.isInstanceOf[PolyType])
-        val alternatives = ctx.typer.resolveOverloaded(allAlts, proto)
-        assert(alternatives.size == 1,
-          i"${if (alternatives.isEmpty) "no" else "multiple"} overloads available for " +
-          i"$method on ${receiver.tpe.widenDealiasKeepAnnots} with targs: $targs%, %; args: $args%, % of types ${args.tpes.map(_.widenDealiasKeepAnnots)}%, %; expectedType: $expectedType." +
-          i"all alternatives: ${allAlts.map(_.symbol.showDcl).mkString(", ")}\n" +
-          i"matching alternatives: ${alternatives.map(_.symbol.showDcl).mkString(", ")}.") // this is parsed from bytecode tree. there's nothing user can do about it
-        alternatives.head
-      }
-      else TermRef(receiver.tpe, denot.symbol)
-    val fun = receiver.select(selected).appliedToTypes(targs)
-
-    val apply = untpd.Apply(fun, args)
-    typer.ApplyToTyped(apply, fun, selected, args, expectedType).result.asInstanceOf[Tree] // needed to handle varargs
-  }
-
   @tailrec
   def sameTypes(trees: List[tpd.Tree], trees1: List[tpd.Tree]): Boolean =
     if (trees.isEmpty) trees.isEmpty
@@ -1361,11 +1326,6 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     transformer.transform(tree)
   }
 
-  def resolveConstructor(atp: Type, args:List[Tree])(implicit ctx: Context): Tree = {
-    val targs = atp.argTypes
-    tpd.applyOverloaded(New(atp.typeConstructor), nme.CONSTRUCTOR, args, targs, atp)
-  }
-
   /** Convert a list of trees to a vararg-compatible tree.
    *  Used to make arguments for methods that accept varargs.
    */
@@ -1385,4 +1345,8 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     ref(defn.ListModule).select(nme.apply)
       .appliedToTypeTree(tpe)
       .appliedToVarargs(trees, tpe)
+
+
+  protected def FunProto(args: List[Tree], resType: Type)(using ctx: Context) =
+    ProtoTypes.FunProtoTyped(args, resType)(ctx.typer, isUsingApply = false)
 }

compiler/src/dotty/tools/dotc/ast/untpd.scala

@@ -4,6 +4,7 @@ package ast
 
 import core._
 import Types._, Contexts._, Constants._, Names._, Flags._
+import dotty.tools.dotc.typer.ProtoTypes
 import Symbols._, StdNames._, Trees._
 import util.{Property, SourceFile, NoSource}
 import util.Spans.Span
@@ -756,4 +757,7 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
     }
     acc(false, tree)
   }
+
+  protected def FunProto(args: List[Tree], resType: Type)(using ctx: Context) =
+    ProtoTypes.FunProto(args, resType)(ctx.typer, isUsingApply = false)
 }

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

@@ -142,8 +142,8 @@ object Annotations {
     def deferred(atp: Type, args: List[Tree])(implicit ctx: Context): Annotation =
       deferred(atp.classSymbol)(New(atp, args))
 
-    def deferredResolve(atp: Type, args: List[Tree])(implicit ctx: Context): Annotation =
-      deferred(atp.classSymbol)(resolveConstructor(atp, args))
+    def deferredResolve(atp: Type, args: List[ast.untpd.Tree])(implicit ctx: 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

@@ -8,6 +8,7 @@ import dotty.tools.tasty.{ TastyReader, TastyHeaderUnpickler }
 import Contexts._, Symbols._, Types._, Names._, StdNames._, NameOps._, Scopes._, Decorators._
 import SymDenotations._, unpickleScala2.Scala2Unpickler._, Constants._, Annotations._, util.Spans._
 import NameKinds.DefaultGetterName
+import ast.{ tpd, untpd }
 import ast.tpd._, util._
 import java.io.{ ByteArrayInputStream, ByteArrayOutputStream, DataInputStream, IOException }
 
@@ -480,18 +481,30 @@ class ClassfileParser(
   }
   // sigToType
 
-  def parseAnnotArg(skip: Boolean = false)(implicit ctx: Context): Option[Tree] = {
+  def parseAnnotArg(skip: Boolean = false)(implicit ctx: Context): Option[untpd.Tree] = {
+
+    // If we encounter an empty array literal, we need the type of the corresponding
+    // parameter to properly type it, but that would require forcing the annotation
+    // early. To avoid this we store annotation arguments as untyped trees
+    import untpd._
+
+    // ... but constants need to actually be typed with a ConstantType, so we
+    // can't rely on type inference, and type them early.
+    def lit(c: Constant): Tree = TypedSplice(ast.tpd.Literal(c))
+
     val tag = in.nextByte.toChar
     val index = in.nextChar
+
+
     tag match {
       case STRING_TAG =>
-        if (skip) None else Some(Literal(Constant(pool.getName(index).toString)))
+        if (skip) None else Some(lit(Constant(pool.getName(index).toString)))
       case BOOL_TAG | BYTE_TAG | CHAR_TAG | SHORT_TAG =>
-        if (skip) None else Some(Literal(pool.getConstant(index, tag)))
+        if (skip) None else Some(lit(pool.getConstant(index, tag)))
       case INT_TAG | LONG_TAG | FLOAT_TAG | DOUBLE_TAG =>
-        if (skip) None else Some(Literal(pool.getConstant(index)))
+        if (skip) None else Some(lit(pool.getConstant(index)))
       case CLASS_TAG =>
-        if (skip) None else Some(Literal(Constant(pool.getType(index))))
+        if (skip) None else Some(lit(Constant(pool.getType(index))))
       case ENUM_TAG =>
         val t = pool.getType(index)
         val n = pool.getName(in.nextChar)
@@ -500,7 +513,7 @@ class ClassfileParser(
         if (skip)
           None
         else if (s != NoSymbol)
-          Some(Literal(Constant(s)))
+          Some(lit(Constant(s)))
         else {
           ctx.warning(s"""While parsing annotations in ${in.file}, could not find $n in enum $module.\nThis is likely due to an implementation restriction: an annotation argument cannot refer to a member of the annotated class (SI-7014).""")
           None
@@ -517,10 +530,7 @@ class ClassfileParser(
         else if (skip) None
         else {
           val elems = arr.toList
-          val elemType =
-            if (elems.isEmpty) defn.ObjectType
-            else ctx.typeComparer.lub(elems.tpes).widen
-          Some(JavaSeqLiteral(elems, TypeTree(elemType)))
+          Some(untpd.JavaSeqLiteral(elems, TypeTree()))
         }
       case ANNOTATION_TAG =>
         parseAnnotation(index, skip) map (_.tree)
@@ -533,12 +543,12 @@ class ClassfileParser(
   def parseAnnotation(attrNameIndex: Char, skip: Boolean = false)(implicit ctx: Context): Option[Annotation] = try {
     val attrType = pool.getType(attrNameIndex)
     val nargs = in.nextChar
-    val argbuf = new ListBuffer[Tree]
+    val argbuf = new ListBuffer[untpd.Tree]
     var hasError = false
     for (i <- 0 until nargs) {
       val name = pool.getName(in.nextChar)
       parseAnnotArg(skip) match {
-        case Some(arg) => argbuf += NamedArg(name, arg)
+        case Some(arg) => argbuf += untpd.NamedArg(name, arg)
         case None => hasError = !skip
       }
     }

compiler/src/dotty/tools/dotc/transform/TreeChecker.scala

@@ -287,6 +287,7 @@ class TreeChecker extends Phase with SymTransformer {
 
     override def typed(tree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree = {
       val tpdTree = super.typed(tree, pt)
+      Typer.assertPositioned(tree)
       if (ctx.erasedTypes)
         // Can't be checked in earlier phases since `checkValue` is only run in
         // Erasure (because running it in Typer would force too much)

compiler/src/dotty/tools/dotc/typer/Applications.scala

@@ -860,14 +860,9 @@ trait Applications extends Compatibility {
       def simpleApply(fun1: Tree, proto: FunProto)(implicit ctx: Context): Tree =
         methPart(fun1).tpe match {
           case funRef: TermRef =>
-            val app =
-              if (proto.allArgTypesAreCurrent())
-                new ApplyToTyped(tree, fun1, funRef, proto.typedArgs(), pt)
-              else
-                new ApplyToUntyped(tree, fun1, funRef, proto, pt)(
-                  using fun1.nullableInArgContext(using argCtx(tree)))
+            val app = ApplyTo(tree, fun1, funRef, proto, pt)
             convertNewGenericArray(
-              postProcessByNameArgs(funRef, app.result).computeNullable())
+              postProcessByNameArgs(funRef, app).computeNullable())
           case _ =>
             handleUnexpectedFunType(tree, fun1)
         }
@@ -991,6 +986,15 @@ trait Applications extends Compatibility {
     }
   }
 
+  /** Typecheck an Apply node with a typed function and possibly-typed arguments coming from `proto` */
+  def ApplyTo(app: untpd.Apply, fun: tpd.Tree, methRef: TermRef, proto: FunProto, resultType: Type)(using ctx: Context): tpd.Tree =
+    val typer = ctx.typer
+    if (proto.allArgTypesAreCurrent())
+      typer.ApplyToTyped(app, fun, methRef, proto.typedArgs(), resultType).result
+    else
+      typer.ApplyToUntyped(app, fun, methRef, proto, resultType)(
+        using fun.nullableInArgContext(using argCtx(app))).result
+
   /** Overridden in ReTyper to handle primitive operations that can be generated after erasure */
   protected def handleUnexpectedFunType(tree: untpd.Apply, fun: Tree)(implicit ctx: Context): Tree =
     if ctx.reporter.errorsReported then

compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala

@@ -399,6 +399,8 @@ object ProtoTypes {
    */
   class FunProtoTyped(args: List[tpd.Tree], resultType: Type)(typer: Typer, isUsingApply: Boolean)(implicit ctx: Context) extends FunProto(args, resultType)(typer, isUsingApply)(ctx) {
     override def typedArgs(norm: (untpd.Tree, Int) => untpd.Tree)(implicit ctx: Context): List[tpd.Tree] = args
+    override def typedArg(arg: untpd.Tree, formal: Type)(implicit ctx: Context): tpd.Tree = arg.asInstanceOf[tpd.Tree]
+    override def allArgTypesAreCurrent()(implicit ctx: Context): Boolean = true
     override def withContext(ctx: Context): FunProtoTyped = this
   }
 

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2295,7 +2295,8 @@ class Typer extends Namer
     trace(i"typing $tree, pt = $pt", typr, show = true) {
       record(s"typed $getClass")
       record("typed total")
-      assertPositioned(tree)
+      if (ctx.phase.isTyper)
+        assertPositioned(tree)
       if (tree.source != ctx.source && tree.source.exists)
         typed(tree, pt, locked)(ctx.withSource(tree.source))
       else

tests/pos-java-interop-separate/array-annot/Annot_1.java

@@ -0,0 +1,3 @@
+public @interface Annot_1 {
+  String[] values() default {};
+}

tests/pos-java-interop-separate/array-annot/Class_1.java

@@ -0,0 +1,8 @@
+public class Class_1 {
+  @Annot_1(values = { "foo", "bar" })
+  void foo() {}
+
+  @Annot_1(values = {})
+  void foo2() {}
+}
+

tests/pos-java-interop-separate/array-annot/Test_2.scala

@@ -0,0 +1 @@
+class Test extends Class_1