Generalizes the allowed inputs to the interpret...

Generalizes the allowed inputs to the interpreter to be any combination
of phrases that can be placed inside a template. Instead of having one
"request" object try to understand the entire combination of phrases,
the code now uses multiple "member handlers" for each request, one
member handler for each phrase.

4 files changed, 269 insertions, 274 deletions

diff --git a/src/compiler/scala/tools/nsc/Interpreter.scala b/src/compiler/scala/tools/nsc/Interpreter.scala
index be954205f2..1833ff1065 100644
--- a/src/compiler/scala/tools/nsc/Interpreter.scala
+++ b/src/compiler/scala/tools/nsc/Interpreter.scala
@@ -10,6 +10,7 @@ import java.io.{File, PrintWriter, StringWriter, Writer}
 import java.lang.{Class, ClassLoader}
 import java.net.{URL, URLClassLoader}
 
+import scala.collection.immutable.ListSet
 import scala.collection.mutable
 import scala.collection.mutable.{ListBuffer, HashSet, ArrayBuffer}
 
@@ -78,6 +79,8 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
   import compiler.CompilationUnit
   import compiler.{Symbol,Name,Type}
   import compiler.nme
+  import compiler.newTermName
+  import compiler.nme.{INTERPRETER_VAR_PREFIX, INTERPRETER_SYNTHVAR_PREFIX}
   import Interpreter.string2code
 
   /** construct an interpreter that reports to Console */
@@ -181,9 +184,27 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
   private def newVarName() = {
     val num = nextVarNameNo
     nextVarNameNo += 1
-    compiler.nme.INTERPRETER_VAR_PREFIX + num
+    INTERPRETER_VAR_PREFIX + num
   }
 
+  /** next internal variable number to use */
+  private var nextInternalVarNo = 0
+
+  /** allocate a fresh internal variable name */
+  private def newInternalVarName() = {
+    val num = nextVarNameNo
+    nextVarNameNo += 1
+    INTERPRETER_SYNTHVAR_PREFIX + num
+  }
+
+
+  /** Check if a name looks like it was generated by newVarName */
+  private def isGeneratedVarName(name: String): Boolean =
+    name.startsWith(INTERPRETER_VAR_PREFIX) && {
+      val suffix = name.drop(INTERPRETER_VAR_PREFIX.length)
+      suffix.forall(_.isDigit)
+    }
+
 
   /** generate a string using a routine that wants to write on a stream */
   private def stringFrom(writer: PrintWriter => Unit): String = {
@@ -259,34 +280,31 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
      *  should be taken.  Removes requests which cannot contribute
      *  useful imports for the specified set of wanted names.
      */
-    def reqsToUse: List[Request] = {
-      /** Loop through the requests in reverse and select
+    def reqsToUse: List[(Request,MemberHandler)] = {
+      /** Loop through a list of MemberHandlers and select
        *  which ones to keep.  'wanted' is the set of
        *  names that need to be imported, and
        *  'shadowed' is the list of names useless to import
        *  because a later request will re-import it anyway.
        */
-      def select(reqs: List[Request], wanted: Set[Name]): List[Request] = {
+      def select(reqs: List[(Request,MemberHandler)], wanted: Set[Name]):
+      List[(Request,MemberHandler)] = {
         reqs match {
           case Nil => Nil
 
-          case req::rest =>
-            val keepit = req.definesImplicit || (req match {
-              case req:ImportReq =>
-                req.importsWildcard ||
-                req.importedNames.exists(wanted.contains)
-              case _ =>
-                req.boundNames.exists(wanted.contains)
-            })
+          case (req,handler)::rest =>
+            val keepit =
+              (handler.definesImplicit ||
+               handler.importsWildcard ||
+               handler.importedNames.exists(wanted.contains(_)) ||
+               handler.boundNames.exists(wanted.contains(_)))
 
             val newWanted =
               if (keepit) {
-                req match {
-                  case req:ImportReq =>
-                    wanted -- req.importedNames ++ req.usedNames
-
-                  case _ => wanted -- req.boundNames
-                }
+                (wanted
+                   ++ handler.usedNames
+                   -- handler.boundNames
+                   -- handler.importedNames)
               } else {
                 wanted
               }
@@ -294,13 +312,18 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
             val restToKeep = select(rest, newWanted)
 
             if(keepit)
-              req :: restToKeep
+              (req,handler) :: restToKeep
             else
               restToKeep
         }
       }
 
-      select(prevRequests.toList.reverse, wanted).reverse
+      val rhpairs = for {
+        req <- prevRequests.toList.reverse
+        handler <- req.handlers
+      } yield (req, handler)
+
+      select(rhpairs, wanted).reverse
     }
 
     val code = new StringBuffer
@@ -321,40 +344,37 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
 
     // loop through previous requests, adding imports
     // for each one
-    for (req <- reqsToUse) {
-      req match {
-        case req:ImportReq =>
+    for ((req,handler) <- reqsToUse) {
           // If the user entered an import, then just use it
 
           // add an import wrapping level if the import might
           // conflict with some other import
-          if(req.importsWildcard ||
-             currentImps.exists(req.importedNames.contains))
+          if(handler.importsWildcard ||
+             currentImps.exists(handler.importedNames.contains))
             if(!currentImps.isEmpty)
               addWrapper()
 
-          code.append(req.line + ";\n")
+          if (handler.member.isInstanceOf[Import])
+            code.append(handler.member.toString + ";\n")
 
           // give wildcard imports a import wrapper all to their own
-          if(req.importsWildcard)
+          if(handler.importsWildcard)
             addWrapper()
           else
-            currentImps ++= req.importedNames
+            currentImps ++= handler.importedNames
 
-        case req =>
           // For other requests, import each bound variable.
           // import them explicitly instead of with _, so that
           // ambiguity errors will not be generated. Also, quote
  	  // the name of the variable, so that we don't need to
  	  // handle quoting keywords separately.
-          for (imv <- req.boundNames) {
+          for (imv <- handler.boundNames) {
             if (currentImps.contains(imv))
               addWrapper()
             code.append("import ")
             code.append(req.objectName + req.accessPath + ".`" + imv + "`;\n")
             currentImps += imv
           }
-      }
     }
 
     addWrapper() // Add one extra wrapper, to prevent warnings
@@ -411,26 +431,20 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
    *  after being parsed.
    */
   private def buildRequest(trees: List[Tree], line: String, lineName: String): Request =
-    trees match {
-      /* This case for assignments is more specialized than desirable: it only
-         handles assignments to an identifier.  It would be better to support
-         arbitrary paths being assigned, but that is technically difficult
-         because of the way objectSourceCode and resultObjectSourceCode are
-         implemented in class Request. */
-      case List(Assign(Ident(lhs), _)) =>
-        new AssignReq(lhs, line, lineName)
-      case _ if trees.forall(t => t.isInstanceOf[ValOrDefDef]) =>
-        new DefReq(line, lineName)
-      case List(_:TermTree) | List(_:Ident) | List(_:Select) =>
-        new ExprReq(line, lineName)
-      case List(_:ModuleDef) => new ModuleReq(line, lineName)
-      case List(_:ClassDef) => new ClassReq(line, lineName)
-      case List(t:TypeDef) if compiler.treeInfo.isAliasTypeDef(t) =>
-        new TypeAliasReq(line, lineName)
-      case List(_:Import) => new ImportReq(line, lineName)
-      case _ =>
-        reporter.error(null, "That kind of statement combination is not supported by the interpreter.")
-        null
+    new Request(line, lineName)
+
+  private def chooseHandler(member: Tree): Option[MemberHandler] =
+    member match {
+      case member: DefDef =>
+          Some(new DefHandler(member))
+      case member: ValDef =>
+          Some(new ValHandler(member))
+      case member@Assign(Ident(_), _) => Some(new AssignHandler(member))
+      case member: ModuleDef => Some(new ModuleHandler(member))
+      case member: ClassDef => Some(new ClassHandler(member))
+      case member: TypeDef => Some(new TypeAliasHandler(member))
+      case member: Import => Some(new ImportHandler(member))
+      case _ => None
     }
 
   /** <p>
@@ -458,6 +472,19 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
       case Some(trees) => trees
     }
 
+    trees match {
+      case List(_:Assign) => ()
+
+      case List(_:TermTree) | List(_:Ident) | List(_:Select) =>
+        // Treat a single bare expression specially.
+        // This is necessary due to it being hard to modify
+        // code at a textual level, and it being hard to
+        // submit an AST to the compiler.
+        return interpret("val "+newVarName()+" = \n"+line)
+
+      case _ => ()
+    }
+
     val lineName = newLineName
 
     // figure out what kind of request
@@ -472,10 +499,6 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
     if (printResults || !succeeded) {
       // print the result
       out.print(clean(interpreterResultString))
-
-      // print out types of functions; they are not printed in the
-      // request printout
-      out.print(clean(req.defTypesSummary))
     }
 
     // book-keeping
@@ -556,94 +579,178 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
   }
 
 
-  /** One line of code submitted by the user for interpretation */
-  private abstract class Request(val line: String, val lineName: String) {
-    val trees = parse(line) match {
-      case Some(ts) => ts
-      case None => Nil
+  /** Class to handle one member among all the members included
+   *  in a single interpreter request.
+   */
+  private sealed abstract class MemberHandler(val member: Tree) {
+    val usedNames: List[Name] = {
+      val ivt = new ImportVarsTraverser(boundNames)
+      ivt.traverseTrees(List(member))
+      ivt.importVars.toList
     }
+    val boundNames: List[Name] = Nil
+    def valAndVarNames: List[Name] = Nil
+    def defNames: List[Name] = Nil
+    val importsWildcard = false
+    val importedNames: Seq[Name] = Nil
+    val definesImplicit =
+      member match {
+        case tree:MemberDef =>
+          tree.mods.hasFlag(symtab.Flags.IMPLICIT)
+        case _ => false
+      }
 
-    /** name to use for the object that will compute "line" */
-    def objectName = lineName + compiler.nme.INTERPRETER_WRAPPER_SUFFIX
+    def extraCodeToEvaluate(req: Request, code: PrintWriter) { }
+    def resultExtractionCode(req: Request, code: PrintWriter) { }
+  }
 
-    /** name of the object that retrieves the result from the above object */
-    def resultObjectName = "RequestResult$" + objectName
+  private class ValHandler(member: ValDef) extends MemberHandler(member) {
+    override val boundNames = List(member.name)
+    override def valAndVarNames = boundNames
 
-    /** whether the trees need a variable name, as opposed to standing
-        alone */
-    val needsVarName: Boolean = false
+    override def resultExtractionCode(req: Request, code: PrintWriter) {
+      val vname = member.name
+      if (member.mods.isPublic &&
+          !(isGeneratedVarName(vname) &&
+            req.typeOf(compiler.encode(vname)) == "Unit"))
+      {
+        code.print(" + \"" + vname + ": " +
+	           string2code(req.typeOf(vname)) +
+	           " = \" + " +
+                   " (if(" +
+	           req.fullPath(vname) +
+                   ".asInstanceOf[AnyRef] != null) " +
+                   " ((if(" +
+	           req.fullPath(vname) +
+	           ".toString.contains('\\n')) " +
+                   " \"\\n\" else \"\") + " +
+                   req.fullPath(vname) + ".toString + \"\\n\") else \"null\\n\") ")
+      }
+    }
+  }
 
-    /** A cache for the chosen variable name, if one has been calculated */
-    var varNameCache: Option[String] = None
+  private class DefHandler(defDef: DefDef) extends MemberHandler(defDef) {
+    override val boundNames = List(defDef.name)
+    override def defNames = boundNames
 
-    /** A computed variable name, if one is needed */
-    def varName = varNameCache match {
-      case None =>
-        varNameCache = Some(newVarName)
-        varNameCache.get
-      case Some(name) =>
-        name
+    override def resultExtractionCode(req: Request, code: PrintWriter) {
+      if (defDef.mods.isPublic)
+        code.print("+\""+string2code(defDef.name)+": "+
+		   string2code(req.typeOf(defDef.name))+"\\n\"")
     }
+  }
 
-    /** list of methods defined */
-    val defNames =
-      for (DefDef(mods, name, _, _, _, _) <- trees if mods.isPublic)
-        yield name
+  private class AssignHandler(member: Assign) extends MemberHandler(member) {
+    val lhs = member. lhs.asInstanceOf[Ident] // an unfortunate limitation
 
-    /** list of val's and var's defined */
-    val valAndVarNames = {
-      val baseNames =
-        for (ValDef(mods, name, _, _) <- trees if mods.isPublic)
-          yield name
+    val helperName = newTermName(newInternalVarName())
+    override val valAndVarNames = List(helperName)
 
-      if (needsVarName)
-        compiler.encode(varName) :: baseNames  // add a var name
-      else
-        baseNames
+    override def extraCodeToEvaluate(req: Request, code: PrintWriter) {
+      code.println("val "+helperName+" = "+member.lhs+";")
     }
 
-    /** list of modules defined */
-    val moduleNames = {
-      val explicit =
-        for (ModuleDef(mods, name, _) <- trees if mods.isPublic)
-          yield name
-      val caseClasses =
-        for {val ClassDef(mods, name, _, _) <- trees
-             mods.isPublic
-             mods.hasFlag(Flags.CASE)}
-        yield name.toTermName
-      explicit ::: caseClasses
+    /** Print out lhs instead of the generated varName */
+    override def resultExtractionCode(req: Request, code: PrintWriter) {
+      code.print(" + \"" + lhs + ": " +
+                 string2code(req.typeOf(compiler.encode(helperName))) +
+                 " = \" + " +
+		 string2code(req.fullPath(helperName))
+		 + " + \"\\n\"")
     }
+  }
+
+  private class ModuleHandler(module: ModuleDef) extends MemberHandler(module) {
+    override val boundNames = List(module.name)
 
-    /** list of classes defined */
-    val classNames =
-      for (ClassDef(mods, name, _, _) <- trees if mods.isPublic)
-        yield name
+    override def resultExtractionCode(req: Request, code: PrintWriter) {
+      code.println(" + \"defined module " +
+		   string2code(module.name)
+		   + "\\n\"")
+    }
+  }
 
-    /** list of type aliases defined */
-    val typeNames =
-      for (t @ TypeDef(mods, name, _, _) <- trees
-           if mods.isPublic && compiler.treeInfo.isAliasTypeDef(t))
-        yield name
+  private class ClassHandler(classdef: ClassDef)
+  extends MemberHandler(classdef)
+  {
+    override val boundNames =
+      List(classdef.name) :::
+      (if (classdef.mods.hasFlag(Flags.CASE))
+         List(classdef.name.toTermName)
+       else
+         Nil)
 
-    /** all (public) names defined by these statements */
-    val boundNames =
-      defNames ::: valAndVarNames ::: moduleNames ::: classNames ::: typeNames
+    // TODO: MemberDef.keyword does not include "trait";
+    // otherwise it could be used here
+    def keyword: String =
+      if (classdef.mods.isTrait) "trait" else "class"
 
-    /** list of names used by this expression */
-    val usedNames: List[Name] = {
-      val ivt = new ImportVarsTraverser(boundNames)
-      ivt.traverseTrees(trees)
-      ivt.importVars.toList
+    override def resultExtractionCode(req: Request, code: PrintWriter) {
+      code.print(
+          " + \"defined " +
+          keyword +
+          " " +
+          string2code(classdef.name) +
+          "\\n\"")
     }
+  }
+
+  private class TypeAliasHandler(typeDef: TypeDef)
+  extends MemberHandler(typeDef)
+  {
+    override val boundNames =
+      if (typeDef.mods.isPublic && compiler.treeInfo.isAliasTypeDef(typeDef))
+        List(typeDef.name)
+      else
+        Nil
+
+    override def resultExtractionCode(req: Request, code: PrintWriter) {
+      code.println(" + \"defined type alias " +
+                   string2code(typeDef.name) + "\\n\"")
+    }
+  }
+
+  private class ImportHandler(imp: Import) extends MemberHandler(imp) {
+    override def resultExtractionCode(req: Request, code: PrintWriter) {
+      code.println("+ \"" + imp.toString + "\\n\"")
+    }
+
+    /** Whether this import includes a wildcard import */
+    override val importsWildcard =
+      imp.selectors.map(_._1).contains(nme.USCOREkw)
+
+    /** The individual names imported by this statement */
+    override val importedNames: Seq[Name] =
+      for {
+        val (_,sel) <- imp.selectors
+        sel != null
+        sel != nme.USCOREkw
+        val name <- List(sel.toTypeName, sel.toTermName)
+      }
+      yield name
+  }
 
-    /** Whether this request defines an implicit.  */
-    def definesImplicit = trees.exists {
-      case tree:MemberDef =>
-        tree.mods.hasFlag(symtab.Flags.IMPLICIT)
-      case _ => false
+  /** One line of code submitted by the user for interpretation */
+  private class Request(val line: String, val lineName: String) {
+    val trees = parse(line) match {
+      case Some(ts) => ts
+      case None => Nil
     }
 
+    /** name to use for the object that will compute "line" */
+    def objectName = lineName + compiler.nme.INTERPRETER_WRAPPER_SUFFIX
+
+    /** name of the object that retrieves the result from the above object */
+    def resultObjectName = "RequestResult$" + objectName
+
+    val handlers: List[MemberHandler] = trees.flatMap(chooseHandler(_))
+
+    /** all (public) names defined by these statements */
+    val boundNames = (ListSet() ++ handlers.flatMap(_.boundNames)).toList
+
+    /** list of names used by this expression */
+    val usedNames: List[Name] = handlers.flatMap(_.usedNames)
+
     def myImportsCode = importsCode(Set.empty ++ usedNames)
 
     /** Code to append to objectName to access anything that
@@ -671,12 +778,10 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
 
         code.print(importsPreamble)
 
-        // the variable to compute, if any
-        if (needsVarName)
-          code.println("  val " + varName + " = ")
-
         code.println(indentCode(toCompute))
 
+        handlers.foreach(_.extraCodeToEvaluate(this,code))
+
         code.println(importsTrailer)
 
         //end the wrapper object
@@ -694,28 +799,13 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
         code.println("object " + resultObjectName)
         code.println("{ val result: String = {")
         code.println(objectName + accessPath + ";")  // evaluate the object, to make sure its constructor is run
-        code.print("\"\"")  // print an initial empty string, so later code can
+        code.print("(\"\"")  // print an initial empty string, so later code can
                             // uniformly be: + morestuff
-        resultExtractionCode(code)
-        code.println("}")
+        handlers.foreach(_.resultExtractionCode(this, code))
+        code.println("\n)}")
         code.println(";}")
       })
 
-    def resultExtractionCode(code: PrintWriter) {
-      for (vname <- valAndVarNames) {
-        code.print(" + \"" + vname + ": " +
-		   string2code(typeOf(vname)) +
-		   " = \" + " +
-                   " (if(" +
-		   fullPath(vname) +
-                   ".asInstanceOf[AnyRef] != null) " +
-                   " ((if(" +
-		   fullPath(vname) +
-		   ".toString.contains('\\n')) " +
-                   " \"\\n\" else \"\") + " +
-                   fullPath(vname) + ".toString + \"\\n\") else \"null\\n\") ")
-      }
-    }
 
     /** Compile the object file.  Returns whether the compilation succeeded.
      *  If all goes well, the "types" map is computed. */
@@ -750,11 +840,14 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
      *  @return       ...
      */
     def findTypes(objRun: compiler.Run): Map[Name, String] = {
+      def valAndVarNames = handlers.flatMap(_.valAndVarNames)
+      def defNames = handlers.flatMap(_.defNames)
+
       def getTypes(names: List[Name], nameMap: Name=>Name): Map[Name, String] = {
       /** the outermost wrapper object */
       val outerResObjSym: Symbol =
         compiler.definitions.getMember(compiler.definitions.EmptyPackage,
-          compiler.newTermName(objectName))
+          newTermName(objectName))
 
       /** the innermost object inside the wrapper, found by
         * following accessPath into the outer one. */
@@ -762,7 +855,7 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
         (accessPath.split("\\.")).foldLeft(outerResObjSym)((sym,name) =>
           if(name == "") sym else
             compiler.atPhase(objRun.typerPhase.next) {
-              sym.info.member(compiler.newTermName(name)) })
+              sym.info.member(newTermName(name)) })
 
       names.foldLeft(Map.empty[Name,String])((map, name) => {
           val rawType =
@@ -802,139 +895,14 @@ class Interpreter(val settings: Settings, out: PrintWriter) {
           (stringFrom(str => orig.printStackTrace(str)), false)
       }
     }
-
-    /** return a summary of the defined methods */
-    def defTypesSummary: String =
-      stringFrom(summ => {
-        for (methname <- defNames)
-          summ.println("" + methname + ": " +
-		       string2code(typeOf(methname)))
-      })
-  }
-
-  /** A sequence of definition's.  val's, var's, def's. */
-  private class DefReq(line: String, lineName: String)
-  extends Request(line, lineName)
-
-  /** Assignment of a single variable: lhs = exp */
-  private class AssignReq(val lhs: Name, line: String, lineName: String)
-  extends Request(line, lineName) {
-    override val needsVarName = true
-
-    /** Perform the assignment, and then return the new value */
-    override def toCompute = "{\n" + line + "\n;\n" + lhs + "\n}"
-
-    /** Print out lhs instead of the generated varName */
-    override def resultExtractionCode(code: PrintWriter) {
-      code.print(" + \"" + lhs + ": " +
-		 string2code(typeOf(compiler.encode(varName))) +
-                 " = \" + " +
-		 string2code(fullPath(varName))
-		 + " + \"\\n\"")
-//      override def resultExtractionCode(code: PrintWriter) {
-//        {wrapperObj; lhs}
-//    }
-    }
   }
 
-  /** A single expression */
-  private class ExprReq(line: String, lineName: String)
-  extends Request(line, lineName) {
-    override val needsVarName = true
-
-    /** Skip the printout if the expression has type Unit */
-    override def resultExtractionCode(code: PrintWriter) {
-      if (typeOf(compiler.encode(varName)) != "Unit")
-	super.resultExtractionCode(code)
-    }
-  }
-
-  /** A module definition */
-  private class ModuleReq(line: String, lineName: String)
-  extends Request(line, lineName) {
-    def moduleName = trees match {
-      case List(ModuleDef(_, name, _)) => name
-    }
-    override def resultExtractionCode(code: PrintWriter) {
-      super.resultExtractionCode(code)
-      code.println(" + \"defined module " +
-		   string2code(moduleName)
-		   + "\\n\"")
-    }
-  }
-
-  /** A class definition */
-  private class ClassReq(line: String, lineName: String)
-  extends Request(line, lineName) {
-    def newClassName = trees match {
-      case List(ClassDef(_, name, _, _)) => name
-    }
-
-    def classdef = trees.head.asInstanceOf[ClassDef]
-
-    // TODO: MemberDef.keyword does not include "trait";
-    // otherwise it could be used here
-    def keyword: String =
-      if (classdef.mods.isTrait) "trait" else "class"
-
-    override def resultExtractionCode(code: PrintWriter) {
-      super.resultExtractionCode(code)
-      code.print(
-          " + \"defined " +
-          keyword +
-          " " +
-          string2code(newClassName) +
-          "\\n\"")
-    }
-  }
-
-  /** a type alias */
-  private class TypeAliasReq(line: String, lineName: String)
-  extends Request(line, lineName) {
-    def newTypeName = trees match {
-      case List(TypeDef(_, name, _, _)) => name
-    }
-
-    override def resultExtractionCode(code: PrintWriter) {
-      super.resultExtractionCode(code)
-      code.println(" + \"defined type alias " + newTypeName + "\\n\"")
-    }
-  }
-
-  /** an import */
-  private class ImportReq(line: String, lineName: String)
-  extends Request(line, lineName) {
-    override val boundNames = Nil
-    override def resultExtractionCode(code: PrintWriter) {
-      code.println("+ \"" + trees.head.toString + "\\n\"")
-    }
-
-    /** Whether this import includes a wildcard import */
-    def importsWildcard =
-      trees.exists {
-        case Import(_, selectors) =>
-          selectors.map(_._1).contains(nme.USCOREkw)
-        case _ => false
-      }
-
-    /** The individual names imported by this statement */
-    def importedNames: Seq[Name] =
-      for {
-        val Import(_, selectors) <- trees
-        val (_,sel) <- selectors
-        sel != null
-        sel != nme.USCOREkw
-        val name <- List(sel.toTypeName, sel.toTermName)
-      }
-      yield name
-  }
-}
-
   class NewLinePrintWriter(out: Writer, autoFlush: Boolean)
   extends PrintWriter(out, autoFlush) {
     def this(out: Writer) = this(out, false)
     override def println() { print("\n"); flush() }
   }
+}
 
 /** Utility methods for the Interpreter. */
 object Interpreter {
diff --git a/src/compiler/scala/tools/nsc/symtab/StdNames.scala b/src/compiler/scala/tools/nsc/symtab/StdNames.scala
index 70597eb5db..9403280384 100644
--- a/src/compiler/scala/tools/nsc/symtab/StdNames.scala
+++ b/src/compiler/scala/tools/nsc/symtab/StdNames.scala
@@ -78,6 +78,7 @@ trait StdNames {
     val INTERPRETER_LINE_PREFIX = "line"
     val INTERPRETER_VAR_PREFIX = "res"
     val INTERPRETER_IMPORT_WRAPPER = "$iw"
+    val INTERPRETER_SYNTHVAR_PREFIX = "synthvar$"
 
     def LOCAL(clazz: Symbol) = newTermName(LOCALDUMMY_PREFIX_STRING + clazz.name+">")
     def TUPLE_FIELD(index: Int) = newTermName(TUPLE_FIELD_PREFIX_STRING + index)
diff --git a/test/files/run/interpreter.check b/test/files/run/interpreter.check
index 7623eb2fbc..1bb6c28486 100644
--- a/test/files/run/interpreter.check
+++ b/test/files/run/interpreter.check
@@ -27,6 +27,11 @@ scala> <console>:5: error: type mismatch;
 
 scala> defined trait PointlessTrait
 
+scala> x: Int = 2
+y: Int = 3
+
+scala> hello
+
 scala> 
 scala> 
 scala> defined class Foo
@@ -151,7 +156,7 @@ scala> <console>:1: error: identifier expected but integer literal found.
 scala> 
 scala> 
 scala> 
-scala>      |      |      |      | res2: scala.xml.Elem = 
+scala>      |      |      |      | res3: scala.xml.Elem = 
 <a>
        <b d="dd" c="c"></b></a>
 
@@ -161,7 +166,7 @@ scala>      |      |      |      |
 scala> 
 scala> 
 scala> 
-scala>      |      |      | res3: java.lang.String = 
+scala>      |      |      | res4: java.lang.String = 
 
        hello
        there
@@ -177,3 +182,16 @@ scala> x: Int = 1
 
 scala> 
 scala> 
+scala> defined class Exp
+defined class Fact
+defined class Term
+
+scala>      |      | <console>:15: warning: match is not exhaustive!
+missing combination           Term
+
+       def f(e: Exp) = e match {  // non-exhaustive warning here
+                       ^
+f: (Exp)Int
+
+scala> 
+scala> 
diff --git a/test/files/run/interpreter.scala b/test/files/run/interpreter.scala
index 5ad9953857..b239b253cf 100644
--- a/test/files/run/interpreter.scala
+++ b/test/files/run/interpreter.scala
@@ -19,6 +19,8 @@ type anotherint = Int
 val four: anotherint = 4
 val bogus: anotherint = "hello"
 trait PointlessTrait
+val (x,y) = (2,3)
+println("hello")
 
 // implicit conversions
 case class Foo(n: int)
@@ -111,6 +113,12 @@ there
 def `match` = 1
 val x = `match`
 
+// multiple classes defined on one line
+sealed class Exp; class Fact extends Exp; class Term extends Exp
+def f(e: Exp) = e match {{  // non-exhaustive warning here
+  case _:Fact => 3
+}}
+
 </code>.text
 
   /** A writer that skips the first line of text.  The first