Generate EnclosingMethod classfile attributes.

This should fix java signatures when they refer to
method type parameters. I unrolled Adriaans previous fix 
for #3249, as this one is more general. Closes #3249, 
review by moors.

4 files changed, 16 insertions, 4 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/icode/BasicBlocks.scala b/src/compiler/scala/tools/nsc/backend/icode/BasicBlocks.scala
index 45d1916ca9..c7cdad7c20 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/BasicBlocks.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/BasicBlocks.scala
@@ -331,7 +331,6 @@ trait BasicBlocks {
      *  and RETURNs easier.
      */
     def enterIgnoreMode = {
-      log("Entering ignore mode in " + fullString)
       ignore = true
     }
 
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
index 7d216dc3aa..0c7455c6c8 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
@@ -199,6 +199,9 @@ abstract class GenJVM extends SubComponent {
     var isParcelableClass = false
 
     def genClass(c: IClass) {
+      val needsEnclosingMethod: Boolean =
+        c.symbol.isClass && c.symbol.asInstanceOf[ClassSymbol].originalOwner.isMethod
+
       clasz = c
       innerClasses = immutable.ListSet.empty
 
@@ -282,12 +285,20 @@ abstract class GenJVM extends SubComponent {
       val ssa = scalaSignatureAddingMarker(jclass, c.symbol)
       addGenericSignature(jclass, c.symbol, c.symbol.owner)
       addAnnotations(jclass, c.symbol.annotations ++ ssa)
+      if (needsEnclosingMethod)  addEnclosingMethodAttribute(jclass, c.symbol)
       emitClass(jclass, c.symbol)
 
       if (c.symbol hasAnnotation BeanInfoAttr)
         genBeanInfoClass(c)
     }
 
+    def addEnclosingMethodAttribute(jclass: JClass, clazz: Symbol) {
+      val sym = clazz.asInstanceOf[ClassSymbol].originalOwner
+      if (sym.isMethod) {
+        jclass.addAttribute(fjbgContext.JEnclosingMethodAttribute(jclass, javaName(sym.enclClass), javaName(sym), javaType(sym)))
+      } else
+        log("Local class %s has non-method owner: %s".format(clazz, sym))
+    }
 
     /**
      * Generate a bean info class that describes the given class.
diff --git a/src/compiler/scala/tools/nsc/symtab/Symbols.scala b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
index f8320595e9..d94b617904 100644
--- a/src/compiler/scala/tools/nsc/symtab/Symbols.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
@@ -1897,6 +1897,10 @@ trait Symbols extends reflect.generic.Symbols { self: SymbolTable =>
     /** The classfile from which this class was loaded. Maybe null. */
     var classFile: AbstractFile = null;
 
+    /** The original owner of this class. Used by the backend to generate
+     *  EnclosingMethod attributes. */
+    var originalOwner: Symbol = initOwner
+
     private var source: AbstractFile = null
     override def sourceFile =
       if (owner.isPackageClass) source else super.sourceFile
diff --git a/src/compiler/scala/tools/nsc/transform/Erasure.scala b/src/compiler/scala/tools/nsc/transform/Erasure.scala
index 906297a4b8..b9d195a01e 100644
--- a/src/compiler/scala/tools/nsc/transform/Erasure.scala
+++ b/src/compiler/scala/tools/nsc/transform/Erasure.scala
@@ -249,9 +249,7 @@ abstract class Erasure extends AddInterfaces with typechecker.Analyzer with ast.
             else ARRAY_TAG.toString+(args map jsig).mkString
           else if (sym.isTypeParameterOrSkolem &&
                   // only refer to type params that will actually make it into the sig, this excludes:
-                  !sym.owner.isTypeParameterOrSkolem && // higher-order type parameters (!sym.owner.isTypeParameterOrSkolem), and parameters of methods
-                  (!sym0.isClass || sym.owner.isClass) // if we're generating the sig for a class, type params must be owned by a class (not a method -- #3249)
-                  )
+                  !sym.owner.isTypeParameterOrSkolem) // higher-order type parameters (!sym.owner.isTypeParameterOrSkolem), and parameters of methods
             TVAR_TAG.toString+sym.name+";"
           else if (sym == AnyClass || sym == AnyValClass || sym == SingletonClass)
             jsig(ObjectClass.tpe)