Java parses leading annotation

Author: som-snytt

compiler/src/dotty/tools/dotc/parsing/JavaParsers.scala

@@ -440,11 +440,11 @@ object JavaParsers {
       }
     }
 
-    def modifiers(inInterface: Boolean): Modifiers = {
+    def modifiers(inInterface: Boolean, annots0: List[Tree] = Nil): Modifiers = {
       var flags: FlagSet = Flags.JavaDefined
       // assumed true unless we see public/private/protected
       var isPackageAccess = true
-      var annots = new ListBuffer[Tree]
+      var annots = ListBuffer.from[Tree](annots0)
       def addAnnot(tpt: Tree) =
         annots += atSpan(in.offset) {
           in.nextToken()
@@ -453,7 +453,7 @@ object JavaParsers {
 
       while (true)
         in.token match {
-          case AT if (in.lookaheadToken != INTERFACE) =>
+          case AT if in.lookaheadToken != INTERFACE =>
             in.nextToken()
             annotation() match {
               case Some(anno) => annots += anno
@@ -1080,24 +1080,30 @@ object JavaParsers {
     /** CompilationUnit ::= [package QualId semi] TopStatSeq
       */
     def compilationUnit(): Tree = {
-      val start = in.offset
+      val buf = ListBuffer.empty[Tree]
+      var start = in.offset
+      val leadingAnnots = if (in.token == AT) annotations() else Nil
       val pkg: RefTree =
-        if (in.token == AT || in.token == PACKAGE) {
-          annotations()
+        if in.token == PACKAGE then
+          if !leadingAnnots.isEmpty then
+            //if (unit.source.file.name != "package-info.java")
+            //  syntaxError(pos, "package annotations must be in file package-info.java")
+            start = in.offset
           accept(PACKAGE)
           val pkg = qualId()
           accept(SEMI)
           pkg
-        }
         else
+          if !leadingAnnots.isEmpty then
+            buf ++= typeDecl(start, modifiers(inInterface = false, annots0 = leadingAnnots))
           Ident(nme.EMPTY_PACKAGE)
       thisPackageName = convertToTypeName(pkg) match {
         case Some(t)  => t.name.toTypeName
         case _        => tpnme.EMPTY
       }
-      val buf = new ListBuffer[Tree]
-      while (in.token == IMPORT)
-        buf ++= importDecl()
+      if (buf.isEmpty)
+        while in.token == IMPORT do
+          buf ++= importDecl()
       while (in.token != EOF && in.token != RBRACE) {
         while (in.token == SEMI) in.nextToken()
         if (in.token != EOF) {

tests/pos/i20026/Empty.java

@@ -0,0 +1,4 @@
+@FunctionalInterface
+public interface JFun {
+	String f(String s);
+}

tests/pos/i20026/JFun.java

@@ -0,0 +1,4 @@
+
+@api.TestInstance(api.TestInstance.Lifecycle.PER_CLASS)
+public class JTest {
+}

tests/pos/i20026/JTest.java

@@ -0,0 +1,6 @@
+
+import api.*;
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+public class KTest {
+}

tests/pos/i20026/KTest.java

@@ -0,0 +1,20 @@
+
+package api;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Inherited
+@Documented
+public @interface TestInstance {
+	enum Lifecycle {
+		PER_CLASS;
+	}
+	Lifecycle value();
+}

tests/pos/i20026/TestInstance.java

@@ -0,0 +1,6 @@
+
+object Test extends App {
+  println {
+    new JTest
+  }
+}