Widen types in names/defaults transformations.

We were getting away with this somehow, but the types are wrong after
typer and that sort of thing is noticed by more people now. I took the
opportunity to add our first -Ycheck:all test, which is at least as much
about helping -Ycheck:all remain in good working order as it is about
this test.

1 files changed, 12 insertions, 13 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
index d1f319311e..932e4548ef 100644
--- a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
@@ -260,19 +260,18 @@ trait NamesDefaults { self: Analyzer =>
     def argValDefs(args: List[Tree], paramTypes: List[Type], blockTyper: Typer): List[ValDef] = {
       val context = blockTyper.context
       val symPs = map2(args, paramTypes)((arg, tpe) => {
-        val byName = isByNameParamType(tpe)
-        val (argTpe, repeated) =
-          if (isScalaRepeatedParamType(tpe)) arg match {
-            case Typed(expr, Ident(tpnme.WILDCARD_STAR)) =>
-              (expr.tpe, true)
-            case _ =>
-              (seqType(arg.tpe), true)
-          } else (arg.tpe, false)
-        val s = context.owner.newValue(unit.freshTermName("x$"), arg.pos)
-        val valType = if (byName) functionType(List(), argTpe)
-                      else if (repeated) argTpe
-                      else argTpe
-        s.setInfo(valType)
+        val byName   = isByNameParamType(tpe)
+        val repeated = isScalaRepeatedParamType(tpe)
+        val argTpe = (
+          if (repeated) arg match {
+            case Typed(expr, Ident(tpnme.WILDCARD_STAR)) => expr.tpe
+            case _                                       => seqType(arg.tpe)
+          }
+          else arg.tpe
+        ).widen // have to widen or types inferred from literal defaults will be singletons
+        val s = context.owner.newValue(unit.freshTermName("x$"), arg.pos) setInfo (
+          if (byName) functionType(Nil, argTpe) else argTpe
+        )
         (context.scope.enter(s), byName, repeated)
       })
       map2(symPs, args) {