Streamline targetName matching tests

Author: odersky

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

@@ -352,7 +352,7 @@ object Denotations {
      */
     def matchingDenotation(site: Type, targetType: Type, targetName: Name)(using Context): SingleDenotation = {
       def qualifies(sym: Symbol) =
-        site.memberInfo(sym).matchesLoosely(targetType) && targetNamesMatch(sym.targetName, targetName)
+        site.memberInfo(sym).matchesLoosely(targetType) && sym.hasTargetName(targetName)
       if (isOverloaded)
         atSignature(targetType.signature, targetName, site, relaxed = true) match {
           case sd: SingleDenotation => sd.matchingDenotation(site, targetType, targetName)
@@ -624,8 +624,7 @@ object Denotations {
           relaxed
         case noMatch =>
           false
-      if sigMatches && targetNamesMatch(symbol.targetName, targetName) then this
-      else NoDenotation
+      if sigMatches && symbol.hasTargetName(targetName) then this else NoDenotation
 
     def matchesImportBound(bound: Type)(using Context): Boolean =
       if bound.isRef(defn.NothingClass) then false
@@ -986,7 +985,7 @@ object Denotations {
     final def last: SingleDenotation = this
 
     def matches(other: SingleDenotation)(using Context): Boolean =
-      targetNamesMatch(symbol.targetName, other.symbol.targetName)
+      symbol.hasTargetName(other.symbol.targetName)
       && {
         val d = signature.matchDegree(other.signature)
         d match
@@ -1285,7 +1284,4 @@ object Denotations {
     util.Stats.record("stale symbol")
     override def getMessage(): String = msg
   }
-
-  def targetNamesMatch(name1: Name, name2: Name): Boolean =
-    name1 == name2 || name1.isEmpty || name2.isEmpty
 }

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

@@ -170,6 +170,10 @@ object NameOps {
       }
     }
 
+    /** Do two target names match? An empty target name matchws any other name. */
+    def matchesTargetName(other: Name) =
+      name == other || name.isEmpty || other.isEmpty
+
     private def functionSuffixStart: Int =
       val first = name.firstPart
       var idx = first.length - 1

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

@@ -512,6 +512,9 @@ object SymDenotations {
     def setTargetName(name: Name): Unit =
       myTargetName = name
 
+    def hasTargetName(name: Name)(using Context): Boolean =
+      targetName.matchesTargetName(name)
+
     /** The name given in a `@targetName` annotation if one is present, `name` otherwise */
     def targetName(using Context): Name =
       if myTargetName == null then

compiler/src/dotty/tools/dotc/core/tasty/NameBuffer.scala

@@ -9,9 +9,9 @@ import TastyBuffer._
 import collection.mutable
 import Names.{Name, chrs, SimpleName, DerivedName, TypeName}
 import NameKinds._
+import NameOps._
 import Decorators._
 import scala.io.Codec
-import Denotations.targetNamesMatch
 import NameTags.{SIGNED, TARGETSIGNED}
 
 class NameBuffer extends TastyBuffer(10000) {
@@ -28,7 +28,7 @@ class NameBuffer extends TastyBuffer(10000) {
         name1 match {
           case SignedName(original, Signature(params, result), target) =>
             nameIndex(original)
-            if !targetNamesMatch(original, target) then nameIndex(target)
+            if !original.matchesTargetName(target) then nameIndex(target)
             nameIndex(result)
             params.foreach {
               case param: TypeName =>
@@ -95,7 +95,7 @@ class NameBuffer extends TastyBuffer(10000) {
         writeByte(tag)
         withLength { writeNameRef(original); writeNat(num) }
       case SignedName(original, Signature(paramsSig, result), target) =>
-        val needsTarget = !targetNamesMatch(original, target)
+        val needsTarget = !original.matchesTargetName(target)
         writeByte(if needsTarget then TARGETSIGNED else SIGNED)
         withLength(
           { writeNameRef(original)

compiler/src/dotty/tools/dotc/reporting/messages.scala

@@ -1086,7 +1086,7 @@ import transform.SymUtils._
   extends DeclarationMsg(OverridesNothingButNameExistsID) {
     def msg =
       val what =
-        if !existing.exists(sd => Denotations.targetNamesMatch(member.targetName, sd.symbol.targetName))
+        if !existing.exists(_.symbol.hasTargetName(member.targetName))
         then "target name"
         else "signature"
       em"""${member} has a different $what than the overridden declaration"""