Add harmonization method for harmonizing numeric types.

Author: odersky

src/dotty/tools/dotc/core/Definitions.scala

@@ -539,7 +539,7 @@ class Definitions {
 
   // ----- primitive value class machinery ------------------------------------------
 
-  lazy val ScalaNumericValueClasses: collection.Set[Symbol] =  Set(
+  lazy val ScalaNumericValueClassList = List(
     ByteClass,
     ShortClass,
     CharClass,
@@ -548,6 +548,7 @@ class Definitions {
     FloatClass,
     DoubleClass)
 
+  lazy val ScalaNumericValueClasses: collection.Set[Symbol] = ScalaNumericValueClassList.toSet
   lazy val ScalaValueClasses: collection.Set[Symbol] = ScalaNumericValueClasses + UnitClass + BooleanClass
 
   lazy val ScalaBoxedClasses = ScalaValueClasses map boxedClass

src/dotty/tools/dotc/core/SymDenotations.scala

@@ -386,6 +386,9 @@ object SymDenotations {
     /** Is symbol a primitive value class? */
     def isPrimitiveValueClass(implicit ctx: Context) = defn.ScalaValueClasses contains symbol
 
+    /** Is symbol a primitive value class? */
+    def isNumericValueClass(implicit ctx: Context) = defn.ScalaNumericValueClasses contains symbol
+
     /** Is symbol a phantom class for which no runtime representation exists? */
     def isPhantomClass(implicit ctx: Context) = defn.PhantomClasses contains symbol
 

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

@@ -1024,6 +1024,26 @@ trait Applications extends Compatibility { self: Typer =>
         result
     }
   }
+
+  def harmonize(trees: List[Tree])(implicit ctx: Context): List[Tree] = {
+    def numericClasses(trees: List[Tree], acc: Set[Symbol]): Set[Symbol] = trees match {
+      case tree :: trees1 =>
+        val sym = tree.tpe.typeSymbol
+        if (sym.isNumericValueClass && tree.tpe.isRef(sym))
+          numericClasses(trees1, acc + sym)
+        else
+          Set()
+      case Nil =>
+        acc
+    }
+    val clss = numericClasses(trees, Set())
+    if (clss.size > 1) {
+      val lub = defn.ScalaNumericValueClassList.find(lubCls =>
+        clss.forall(defn.isValueSubClass(_, lubCls))).get.typeRef
+      trees.mapConserve(tree => adaptInterpolated(tree, lub, tree))
+    }
+    else trees
+  }
 }
 
 /*