Slighly faster phantom erasure checks.

Author: nicolasstucki

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

@@ -981,8 +981,8 @@ class Definitions {
     cls
   }
 
-  def isPhantomAnyClass(sym: Symbol)(implicit ctx: Context): Boolean =
-    sym.name == tpnme.Any && (sym.owner eq PhantomClass)
+  def isPhantomAnyOrNothingClass(sym: Symbol)(implicit ctx: Context): Boolean =
+    (sym.name == tpnme.Any || sym.name == tpnme.Nothing) && (sym.owner eq PhantomClass)
 
   def isPhantomNothingClass(sym: Symbol)(implicit ctx: Context): Boolean =
     sym.name == tpnme.Nothing && (sym.owner eq PhantomClass)

compiler/src/dotty/tools/dotc/core/TypeErasure.scala

@@ -364,7 +364,7 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean
       else if (semiEraseVCs && isDerivedValueClass(sym)) eraseDerivedValueClassRef(tp)
       else if (sym == defn.ArrayClass) apply(tp.appliedTo(TypeBounds.empty)) // i966 shows that we can hit a raw Array type.
       else if (defn.isSyntheticFunctionClass(sym)) defn.erasedFunctionType(sym)
-      else if (defn.isPhantomAnyClass(tp.symbol) || defn.isPhantomNothingClass(tp.symbol)) defn.ErasedPhantomType
+      else if (defn.isPhantomAnyOrNothingClass(tp.symbol)) defn.ErasedPhantomType
       else eraseNormalClassRef(tp)
     case tp: RefinedType =>
       val parent = tp.parent
@@ -507,7 +507,7 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean
         }
         if (defn.isSyntheticFunctionClass(sym))
           sigName(defn.erasedFunctionType(sym))
-        else if (defn.isPhantomAnyClass(tp.symbol) || defn.isPhantomNothingClass(tp.symbol))
+        else if (defn.isPhantomAnyOrNothingClass(tp.symbol))
           sigName(defn.ErasedPhantomType)
         else
           normalizeClass(sym.asClass).fullName.asTypeName