Use hasNamedArgs instead of repeating test inline.

Author: odersky

src/dotty/tools/dotc/ast/TreeInfo.scala

@@ -215,6 +215,10 @@ trait TreeInfo[T >: Untyped <: Type] { self: Trees.Instance[T] =>
     case _                   => false
   }
 
+  /** Does this list contain a named argument tree? */
+  def hasNamedArg(args: List[Any]) = args exists isNamedArg
+  val isNamedArg = (arg: Any) => arg.isInstanceOf[Trees.NamedArg[_]]
+
   /** Is this pattern node a catch-all (wildcard or variable) pattern? */
   def isDefaultCase(cdef: CaseDef) = cdef match {
     case CaseDef(pat, EmptyTree, _) => isWildcardArg(pat)

src/dotty/tools/dotc/typer/Applications.scala

@@ -29,8 +29,6 @@ import language.implicitConversions
 
 object Applications {
   import tpd._
-  private val isNamedArg = (arg: Any) => arg.isInstanceOf[Trees.NamedArg[_]]
-  def hasNamedArg(args: List[Any]) = args exists isNamedArg
 
   def extractorMemberType(tp: Type, name: Name, errorPos: Position = NoPosition)(implicit ctx:Context) = {
     val ref = tp.member(name).suchThat(_.info.isParameterless)
@@ -1061,10 +1059,8 @@ trait Applications extends Compatibility { self: Typer =>
 
         def narrowByShapes(alts: List[TermRef]): List[TermRef] = {
           if (normArgs exists (_.isInstanceOf[untpd.Function]))
-            if (args exists (_.isInstanceOf[Trees.NamedArg[_]]))
-              narrowByTrees(alts, args map treeShape, resultType)
-            else
-              narrowByTypes(alts, normArgs map typeShape, resultType)
+            if (hasNamedArg(args)) narrowByTrees(alts, args map treeShape, resultType)
+            else narrowByTypes(alts, normArgs map typeShape, resultType)
           else
             alts
         }

src/dotty/tools/dotc/typer/TypeAssigner.scala

@@ -395,7 +395,7 @@ trait TypeAssigner {
         errorType(s"named and positional type arguments may not be mixed", arg.pos)
     }
     val ownType =
-      if (args.head.isInstanceOf[NamedArg]) (tycon.tpe /: args)(refineNamed)
+      if (hasNamedArg(args)) (tycon.tpe /: args)(refineNamed)
       else if (sameLength(tparams, args)) tycon.tpe.appliedTo(args.tpes)
       else errorType(d"wrong number of type arguments for ${tycon.tpe}, should be ${tparams.length}", tree.pos)
     tree.withType(ownType)

src/dotty/tools/dotc/typer/Typer.scala

@@ -17,6 +17,7 @@ import SymDenotations._
 import Annotations._
 import Names._
 import NameOps._
+import Applications._
 import Flags._
 import Decorators._
 import ErrorReporting._
@@ -892,7 +893,7 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
     else {
       var args = tree.args
       val args1 =
-        if (args.head.isInstanceOf[untpd.NamedArg])
+        if (hasNamedArg(args))
           for (arg @ NamedArg(id, argtpt) <- args) yield {
             val argtpt1 = typedType(argtpt)
             cpy.NamedArg(arg)(id, argtpt1).withType(argtpt1.tpe)