SI-6221 inference with Function1 subtypes.

There appears to be no upper bound on the number of places
we have to remove calls to typeSymbol and introduce calls to
baseType. This one was type inference for function parameter
types: worked when expected type was A => B, but not if there
was an implicit conversion from A => B to the expected type.

7 files changed, 74 insertions, 7 deletions

diff --git a/test/files/neg/names-defaults-neg.check b/test/files/neg/names-defaults-neg.check
index f6bd703e1f..cdc12c2490 100644
--- a/test/files/neg/names-defaults-neg.check
+++ b/test/files/neg/names-defaults-neg.check
@@ -125,9 +125,12 @@ names-defaults-neg.scala:134: error: missing parameter type for expanded functio
 names-defaults-neg.scala:135: error: parameter 'a' is already specified at parameter position 1
   val taf3 = testAnnFun(b = _: String, a = get(8))
                                          ^
-names-defaults-neg.scala:136: error: wrong number of parameters; expected = 2
+names-defaults-neg.scala:136: error: missing parameter type for expanded function ((x$3) => testAnnFun(x$3, ((x$4) => b = x$4)))
   val taf4: (Int, String) => Unit = testAnnFun(_, b = _)
-                                              ^
+                                               ^
+names-defaults-neg.scala:136: error: missing parameter type for expanded function ((x$4) => b = x$4)
+  val taf4: (Int, String) => Unit = testAnnFun(_, b = _)
+                                                      ^
 names-defaults-neg.scala:144: error: variable definition needs type because 'x' is used as a named argument in its body.
   def t3 { var x = t.f(x = 1) }
                ^
@@ -165,4 +168,4 @@ names-defaults-neg.scala:180: error: reference to x is ambiguous; it is both a m
   class u18 { var x: Int = u.f(x = 1) }
                                  ^
 four warnings found
-41 errors found
+42 errors found
diff --git a/test/files/neg/t1181.check b/test/files/neg/t1181.check
index 3724752a85..13b73d5381 100644
--- a/test/files/neg/t1181.check
+++ b/test/files/neg/t1181.check
@@ -1,8 +1,10 @@
 t1181.scala:8: warning: a pure expression does nothing in statement position; you may be omitting necessary parentheses
      case (Nil, Nil) => map
                         ^
-t1181.scala:9: error: missing parameter type
+t1181.scala:9: error: type mismatch;
+ found   : scala.collection.immutable.Map[Symbol,Symbol]
+ required: Symbol
      _ => buildMap(map.updated(keyList.head, valueList.head), keyList.tail, valueList.tail)
-     ^
+                  ^
 one warning found
 one error found
diff --git a/test/files/neg/t556.check b/test/files/neg/t556.check
index c278e13991..5135dc92ef 100644
--- a/test/files/neg/t556.check
+++ b/test/files/neg/t556.check
@@ -1,4 +1,4 @@
-t556.scala:3: error: wrong number of parameters; expected = 1
+t556.scala:3: error: missing parameter type
   def g:Int = f((x,y)=>x)
-                     ^
+                 ^
 one error found
diff --git a/test/files/pos/t6221.scala b/test/files/pos/t6221.scala
new file mode 100644
index 0000000000..dd7776f596
--- /dev/null
+++ b/test/files/pos/t6221.scala
@@ -0,0 +1,29 @@
+class MyFunc[-A, +B] extends (A => B) { def apply(x: A): B = ??? }
+
+class MyCollection[A] {
+  def map[B](f: MyFunc[A, B]): MyCollection[B] = new MyCollection[B]
+}
+
+class OtherFunc[-A, +B] {}
+
+object Test {
+  implicit def functionToMyFunc[A, B](f: A => B): MyFunc[A, B] = new MyFunc
+
+  implicit def otherFuncToMyFunc[A, B](f: OtherFunc[A, B]): MyFunc[A, B] = new MyFunc
+
+  def main(args: Array[String]) {
+    val col = new MyCollection[Int]
+
+    // Doesn't compile: error: missing parameter type for expanded function ((x$1) => x$1.toString)
+    println(col.map(_.toString))
+
+    // Doesn't compile: error: missing parameter type
+    println(col.map(x => x.toString))
+
+    // Does compile
+    println(col.map((x: Int) => x.toString))
+
+    // Does compile (even though type params of OtherFunc not given)
+    println(col.map(new OtherFunc))
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/t6221.check b/test/files/run/t6221.check
new file mode 100644
index 0000000000..aa1bdd0e6e
--- /dev/null
+++ b/test/files/run/t6221.check
@@ -0,0 +1 @@
+((x) => x.$percent(2).$eq$eq(0))
diff --git a/test/files/run/t6221/Macros_1.scala b/test/files/run/t6221/Macros_1.scala
new file mode 100644
index 0000000000..c9500626d8
--- /dev/null
+++ b/test/files/run/t6221/Macros_1.scala
@@ -0,0 +1,22 @@
+import language.experimental.macros
+import language.implicitConversions
+import scala.reflect.macros.Context
+import scala.reflect.runtime.universe.Tree
+
+class ReflectiveClosure[A, B](val tree: Tree, fn: A => B) extends (A => B) {
+  def apply(x: A) = fn(x)
+}
+
+object ReflectiveClosure {
+  implicit def reflectClosure[A, B](f: A => B): ReflectiveClosure[A, B] = macro Macros.reflectiveClosureImpl[A, B]
+}
+
+object Macros {
+  def reflectiveClosureImpl[A, B](c: Context)(f: c.Expr[A => B]): c.Expr[ReflectiveClosure[A, B]] = {
+    import c.universe._
+    val u = treeBuild.mkRuntimeUniverseRef
+    val m = EmptyTree
+    val tree = c.Expr[scala.reflect.runtime.universe.Tree](Select(c.reifyTree(u, m, f.tree), newTermName("tree")))
+    c.universe.reify(new ReflectiveClosure(tree.splice, f.splice))
+  }
+}
diff --git a/test/files/run/t6221/Test_2.scala b/test/files/run/t6221/Test_2.scala
new file mode 100644
index 0000000000..9f6b2280a7
--- /dev/null
+++ b/test/files/run/t6221/Test_2.scala
@@ -0,0 +1,10 @@
+object Test extends App {
+  implicit class PimpedList[T](val list: List[T]) {
+    def query(predicate: ReflectiveClosure[T, Boolean]): List[T] = {
+      println(predicate.tree)
+      list filter predicate
+    }
+  }
+
+  List(1, 2, 3).query(x => x % 2 == 0)
+}
\ No newline at end of file