Minor restructuring in Implicits.

Another case where I tried to get into the performance party but ended
up playing dungeons and dragons next door. However I did come away with
an attractive tablecloth, which I draped over Implicits.scala before
waving my magic wand.

TRANSLATION: it's probably not faster but it's still better.

3 files changed, 17 insertions, 7 deletions

diff --git a/src/compiler/scala/reflect/internal/Definitions.scala b/src/compiler/scala/reflect/internal/Definitions.scala
index 5802174a5b..092c478bef 100644
--- a/src/compiler/scala/reflect/internal/Definitions.scala
+++ b/src/compiler/scala/reflect/internal/Definitions.scala
@@ -72,10 +72,11 @@ trait Definitions extends reflect.api.StandardDefinitions {
       clazz
     }
 
-    def isNumericSubClass(sub: Symbol, sup: Symbol) = {
-      val cmp = for (w1 <- numericWeight get sub ; w2 <- numericWeight get sup) yield w2 % w1
-      cmp exists (_ == 0)
-    }
+    def isNumericSubClass(sub: Symbol, sup: Symbol) = (
+         (numericWeight contains sub)
+      && (numericWeight contains sup)
+      && (numericWeight(sup) % numericWeight(sub) == 0)
+    )
 
     /** Is symbol a numeric value class? */
     def isNumericValueClass(sym: Symbol): Boolean =
diff --git a/src/compiler/scala/reflect/internal/Symbols.scala b/src/compiler/scala/reflect/internal/Symbols.scala
index 1b1d26d038..65b60bfa39 100644
--- a/src/compiler/scala/reflect/internal/Symbols.scala
+++ b/src/compiler/scala/reflect/internal/Symbols.scala
@@ -1250,6 +1250,9 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
     final def isNumericSubClass(that: Symbol): Boolean =
       definitions.isNumericSubClass(this, that)
 
+    final def isWeakSubClass(that: Symbol) =
+      isSubClass(that) || isNumericSubClass(that)
+
 // ------ overloaded alternatives ------------------------------------------------------
 
     def alternatives: List[Symbol] =
diff --git a/src/compiler/scala/reflect/internal/Types.scala b/src/compiler/scala/reflect/internal/Types.scala
index 0f8d28ff03..a69db8e0f4 100644
--- a/src/compiler/scala/reflect/internal/Types.scala
+++ b/src/compiler/scala/reflect/internal/Types.scala
@@ -5559,9 +5559,15 @@ A type's typeSymbol should never be inspected directly.
         isSubType(tp1, tp2)
     }
 
-  def isNumericSubType(tp1: Type, tp2: Type) =
-    isNumericValueType(tp1) && isNumericValueType(tp2) &&
-    isNumericSubClass(tp1.typeSymbol, tp2.typeSymbol)
+  /** The isNumericValueType tests appear redundant, but without them
+   *  test/continuations-neg/function3.scala goes into an infinite loop.
+   *  (Even if the calls are to typeSymbolDirect.)
+   */
+  def isNumericSubType(tp1: Type, tp2: Type) = (
+       isNumericValueType(tp1)
+    && isNumericValueType(tp2)
+    && isNumericSubClass(tp1.typeSymbol, tp2.typeSymbol)
+  )
 
   private val lubResults = new mutable.HashMap[(Int, List[Type]), Type]
   private val glbResults = new mutable.HashMap[(Int, List[Type]), Type]