fix #2268

4 files changed, 21 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 8f91c823aa..d7c5ed2b33 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -1007,7 +1007,11 @@ trait Namers { self: Analyzer =>
               }
             }
 
-            val defTpt = subst(copyUntyped(vparam.tpt))
+            val defTpt = subst(copyUntyped(vparam.tpt match {
+              // default getter for by-name params
+              case AppliedTypeTree(_, List(arg)) if sym.hasFlag(BYNAMEPARAM) => arg
+              case t => t
+            }))
             val defRhs = copyUntyped(vparam.rhs)
 
             val defaultTree = atPos(vparam.pos.focus) {
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index fef0dd0282..d9471c6008 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1412,7 +1412,11 @@ trait Typers { self: Analyzer =>
                 else if (sym1.isSkolem) matches(sym, sym1.deSkolemize)
                 else super[SubstTypeMap].matches(sym, sym1)
             }
-            subst(tpt1.tpe)
+            // allow defaults on by-name parameters
+            if (sym hasFlag BYNAMEPARAM)
+              if (tpt1.tpe.typeArgs.isEmpty) WildcardType // during erasure tpt1 is Funciton0
+              else subst(tpt1.tpe.typeArgs(0))
+            else subst(tpt1.tpe)
           } else tpt1.tpe
           newTyper(typer1.context.make(vdef, sym)).transformedOrTyped(vdef.rhs, tpt2)
         }
diff --git a/test/files/run/names-defaults.check b/test/files/run/names-defaults.check
index e9381760ce..937f95962b 100644
--- a/test/files/run/names-defaults.check
+++ b/test/files/run/names-defaults.check
@@ -72,6 +72,11 @@ get: 1
 get: 2
 get: 2
 3
+0
+get: 20
+get: 20
+20
+0
 dlkfj0dlkfj102
 lskf2dkflj2
 dlkd5nixda10nixdadklfj1dklfj
diff --git a/test/files/run/names-defaults.scala b/test/files/run/names-defaults.scala
index 1d737bb0c7..8e8c8a1e4a 100644
--- a/test/files/run/names-defaults.scala
+++ b/test/files/run/names-defaults.scala
@@ -127,6 +127,12 @@ object Test extends Application {
   def bn2(a: Int, b: => Int)(c: Int = b) = a + b
   println(bn2(b = get(2), a = get(1))()) // should get: 1, 2, 2
 
+  def bn3(a: => Int = get(10)) = 0
+  def bn4(a: => Int = get(20)) = {a; a}
+  println(bn3())
+  println(bn4())
+  println(bn4(a = 0))
+
 
   // constructors
   val a1 = new A(b = "dlkfj")(d = 102)