Merge pull request scala#577 from lrytz/wip/t2488

Fix SI-2488: allow named arg, in original position, before positionals

Author: Adriaan Moors

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

@@ -617,7 +617,8 @@ trait Infer {
           } else if (argPos.contains(pos)) { // parameter specified twice
             namesOK = false
           } else {
-            positionalAllowed = false
+            if (index != pos)
+              positionalAllowed = false
             argPos(index) = pos
           }
           index += 1

test/files/neg/t2488.check

@@ -0,0 +1,31 @@
+t2488.scala:7: error: overloaded method value f with alternatives:
+  ()Int <and>
+  (a: Int,b: Int)Int
+ cannot be applied to (b: Int, Int)
+  println(c.f(b = 2, 2))
+            ^
+t2488.scala:8: error: overloaded method value f with alternatives:
+  ()Int <and>
+  (a: Int,b: Int)Int
+ cannot be applied to (a: Int, c: Int)
+  println(c.f(a = 2, c = 2))
+            ^
+t2488.scala:9: error: overloaded method value f with alternatives:
+  ()Int <and>
+  (a: Int,b: Int)Int
+ cannot be applied to (Int, c: Int)
+  println(c.f(2, c = 2))
+            ^
+t2488.scala:10: error: overloaded method value f with alternatives:
+  ()Int <and>
+  (a: Int,b: Int)Int
+ cannot be applied to (c: Int, Int)
+  println(c.f(c = 2, 2))
+            ^
+t2488.scala:11: error: overloaded method value f with alternatives:
+  ()Int <and>
+  (a: Int,b: Int)Int
+ cannot be applied to (Int)
+  println(c.f(2))
+            ^
+5 errors found

test/files/neg/t2488.scala

@@ -0,0 +1,12 @@
+class C {
+  def f(a:Int, b:Int) = 1
+  def f() = 2
+}
+object Test extends App {
+  val c = new C()
+  println(c.f(b = 2, 2))
+  println(c.f(a = 2, c = 2))
+  println(c.f(2, c = 2))
+  println(c.f(c = 2, 2))
+  println(c.f(2))
+}

test/files/run/t2488.check

@@ -0,0 +1,4 @@
+1
+1
+1
+2

test/files/run/t2488.scala

@@ -0,0 +1,11 @@
+class C {
+  def f(a:Int, b:Int) = 1
+  def f() = 2
+}
+object Test extends App {
+  val c = new C()
+  println(c.f(a = 1,2))
+  println(c.f(a = 1, b = 2))
+  println(c.f(b = 2, a = 1))
+  println(c.f())
+}