Initialize static fields correctly

Currently the only way to put initializer inside
the static constructor is to use @static. However, CheckStatic
restricts that @static can only used in companion object, which
is a user-facing check, as MoveStatics can handle @static member
in the class.

We need a refactoring to make @static a general mechanism that
includes a phase to generate the static constructor. This needs
to be addressed in another PR.

Author: liufengyun

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -58,8 +58,8 @@ class Compiler {
          new CheckReentrant,         // Internal use only: Check that compiled program has no data races involving global vars
          new ElimPackagePrefixes,    // Eliminate references to package prefixes in Select nodes
          new CookComments,           // Cook the comments: expand variables, doc, etc.
-         new CompleteJavaEnums) ::   // Fill in constructors for Java enums
-    List(new CheckStatic,            // Check restrictions that apply to @static members
+         new CheckStatic) ::         // Check restrictions that apply to @static members
+    List(new CompleteJavaEnums,      // Fill in constructors for Java enums
          new ElimRepeated,           // Rewrite vararg parameters and arguments
          new ExpandSAMs,             // Expand single abstract method closures to anonymous classes
          new ProtectedAccessors,     // Add accessors for protected members

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

@@ -117,10 +117,11 @@ class CompleteJavaEnums extends MiniPhase with InfoTransformer { thisPhase =>
     val moduleCls = clazz.companionClass
     val moduleRef = ref(clazz.companionModule)
 
-    val enums = moduleCls.info.decls.filter(member => member.isTerm && member.isAllOf(EnumValue))
+    val enums = moduleCls.info.decls.filter(member => member.isAllOf(EnumValue))
     for { enumValue <- enums }
     yield {
-      val fieldSym = ctx.newSymbol(clazz, enumValue.name.asTermName, EnumValue, enumValue.info)
+      val fieldSym = ctx.newSymbol(clazz, enumValue.name.asTermName, EnumValue | JavaStatic, enumValue.info)
+      fieldSym.addAnnotation(Annotations.Annotation(defn.ScalaStaticAnnot))
       ValDef(fieldSym, moduleRef.select(enumValue))
     }
   }