Refactor away duplication between -Ydelambdafy:{inline,method}

1 files changed, 40 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/TreeGen.scala b/src/compiler/scala/tools/nsc/ast/TreeGen.scala
index d4ac21a6b8..4ac6672727 100644
--- a/src/compiler/scala/tools/nsc/ast/TreeGen.scala
+++ b/src/compiler/scala/tools/nsc/ast/TreeGen.scala
@@ -256,4 +256,44 @@ abstract class TreeGen extends scala.reflect.internal.TreeGen with TreeDSL {
     val stats1 = if (stats.isEmpty) List(Literal(Constant(()))) else stats
     mkNew(Nil, noSelfType, stats1, NoPosition, NoPosition)
   }
+
+  /**
+   * Create a method based on a Function
+   *
+   * Used both to under `-Ydelambdafy:method` create a lifted function and
+   * under `-Ydelamdafy:inline` to create the apply method on the anonymous
+   * class.
+   *
+   * It creates a method definition with value params cloned from the
+   * original lambda. Then it calls a supplied function to create
+   * the body and types the result. Finally
+   * everything is wrapped up in a DefDef
+   *
+   * @param owner The owner for the new method
+   * @param name name for the new method
+   * @param additionalFlags flags to be put on the method in addition to FINAL
+   */
+  def mkMethodFromFunction(localTyper: analyzer.Typer)
+                          (fun: Function, owner: Symbol, name: TermName, additionalFlags: FlagSet = NoFlags) = {
+    val funParams = fun.vparams map (_.symbol)
+    val formals :+ restpe = fun.tpe.typeArgs
+
+    val methSym = owner.newMethod(name, fun.pos, FINAL | additionalFlags)
+
+    val paramSyms = map2(formals, fun.vparams) {
+      (tp, vparam) => methSym.newSyntheticValueParam(tp, vparam.name)
+    }
+
+    methSym setInfo MethodType(paramSyms, restpe.deconst)
+
+    fun.body.substituteSymbols(funParams, paramSyms)
+    fun.body changeOwner (fun.symbol -> methSym)
+
+    val methDef = DefDef(methSym, fun.body)
+
+    // Have to repack the type to avoid mismatches when existentials
+    // appear in the result - see SI-4869.
+    methDef.tpt setType localTyper.packedType(fun.body, methSym).deconst
+    methDef
+  }
 }