Merge pull request scala#10644 from som-snytt/issue/9714-java-names-singleton

Allow module lookup from Java

Author: lrytz

src/compiler/scala/tools/nsc/typechecker/Contexts.scala

@@ -1316,8 +1316,20 @@ trait Contexts { self: Analyzer =>
     }
 
     final def javaFindMember(pre: Type, name: Name, qualifies: Symbol => Boolean): (Type, Symbol) = {
-      val sym = pre.member(name).filter(qualifies)
       val preSym = pre.typeSymbol
+      val sym = {
+        def asModule =
+          if (name.isTypeName && nme.isModuleName(name))
+            pre.member(name.dropModule.toTermName) match {
+              case nope @ NoSymbol => nope
+              case member          => member.filter(qualifies).moduleClass
+            }
+          else NoSymbol
+        pre.member(name) match {
+          case NoSymbol => asModule
+          case member   => member.filter(qualifies)
+        }
+      }
       if (sym.exists || preSym.isPackageClass || !preSym.isClass) (pre, sym)
       else {
         // In Java code, static inner classes, which we model as members of the companion object,

src/compiler/scala/tools/nsc/typechecker/Typers.scala

@@ -5356,9 +5356,8 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
       // For Java, instance and static members are in the same scope, but we put the static ones in the companion object
       // so, when we can't find a member in the class scope, check the companion
       def inCompanionForJavaStatic(cls: Symbol, name: Name): Symbol =
-        if (!(context.unit.isJava && cls.isClass)) NoSymbol else {
-          context.javaFindMember(cls.typeOfThis, name, _.isStaticMember)._2
-        }
+        if (!(context.unit.isJava && cls.isClass)) NoSymbol
+        else context.javaFindMember(cls.typeOfThis, name, s => s.isStaticMember || s.isStaticModule)._2
 
       /* Attribute a selection where `tree` is `qual.name`.
        * `qual` is already attributed.
@@ -5379,7 +5378,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
             if (!isPastTyper && isUniversalMember(result.symbol))
               context.warning(tree.pos, s"dubious usage of ${result.symbol} with unit value", WarningCategory.LintUniversalMethods)
 
-          val sym = tree.symbol orElse member(qual.tpe, name) orElse inCompanionForJavaStatic(qual.tpe.typeSymbol, name)
+          val sym = tree.symbol orElse member(qualTp, name) orElse inCompanionForJavaStatic(qualTp.typeSymbol, name)
           if ((sym eq NoSymbol) && name != nme.CONSTRUCTOR && mode.inAny(EXPRmode | PATTERNmode)) {
             // symbol not found? --> try to convert implicitly to a type that does have the required
             // member.  Added `| PATTERNmode` to allow enrichment in patterns (so we can add e.g., an

src/reflect/scala/reflect/internal/Names.scala

@@ -519,7 +519,7 @@ trait Names extends api.Names {
 
     def dropLocal: TermName      = toTermName stripSuffix NameTransformer.LOCAL_SUFFIX_STRING
     def dropSetter: TermName     = toTermName stripSuffix NameTransformer.SETTER_SUFFIX_STRING
-    def dropModule: ThisNameType = this stripSuffix NameTransformer.MODULE_SUFFIX_STRING
+    def dropModule: ThisNameType = stripSuffix(NameTransformer.MODULE_SUFFIX_STRING)
     def localName: TermName      = getterName append NameTransformer.LOCAL_SUFFIX_STRING
     def setterName: TermName     = getterName append NameTransformer.SETTER_SUFFIX_STRING
     def getterName: TermName     = dropTraitSetterSeparator.dropSetter.dropLocal

test/files/run/t9714/J.java

@@ -0,0 +1,14 @@
+
+package p;
+
+public class J {
+	public static J j = new J();
+	public static p.J f() {
+		return p.J.j;
+	}
+	public static p.Module$ module() {
+		return p.Module$.MODULE$;
+	}
+
+	public String toString() { return "J"; }
+}

test/files/run/t9714/Module.scala

@@ -0,0 +1,10 @@
+package p {
+  object Module {
+    override def toString = "Module"
+  }
+}
+
+object Test extends App {
+  assert(p.J.f().toString == "J")
+  assert(p.J.module().toString == "Module")
+}