Enter symbols under their target names after erasure

Enter symbols under their target names in their parent scope after erasure.

Fixes #13252

Author: odersky

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

@@ -257,10 +257,6 @@ object Scopes {
       e
     }
 
-    /** create and enter a scope entry */
-    protected def newScopeEntry(sym: Symbol)(using Context): ScopeEntry =
-      newScopeEntry(sym.name, sym)
-
     private def enterInHash(e: ScopeEntry)(using Context): Unit = {
       val idx = e.name.hashCode & (hashTable.length - 1)
       e.tail = hashTable(idx)
@@ -273,7 +269,11 @@ object Scopes {
       if (sym.isType && ctx.phaseId <= typerPhase.id)
         assert(lookup(sym.name) == NoSymbol,
           s"duplicate ${sym.debugString}; previous was ${lookup(sym.name).debugString}") // !!! DEBUG
-      newScopeEntry(sym)
+      enter(sym.name, sym)
+    }
+
+    final def enter[T <: Symbol](name: Name, sym: T)(using Context): T = {
+      newScopeEntry(name, sym)
       sym
     }
 
@@ -375,7 +375,7 @@ object Scopes {
       }
       if ((e eq null) && (synthesize != null)) {
         val sym = synthesize(name)
-        if (sym.exists) newScopeEntry(sym) else e
+        if (sym.exists) newScopeEntry(sym.name, sym) else e
       }
       else e
     }

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

@@ -654,7 +654,14 @@ class TypeErasure(sourceLanguage: SourceLanguage, semiEraseVCs: Boolean, isConst
               tr1 :: trs1.filterNot(_.isAnyRef)
             case nil => nil
           }
-        val erasedDecls = decls.filteredScope(sym => !sym.isType || sym.isClass)
+        var erasedDecls = decls.filteredScope(sym => !sym.isType || sym.isClass).openForMutations
+        for dcl <- erasedDecls.iterator do
+          if dcl.lastKnownDenotation.unforcedAnnotation(defn.TargetNameAnnot).isDefined
+             && dcl.targetName != dcl.name
+          then
+            if erasedDecls eq decls then erasedDecls = erasedDecls.cloneScope
+            erasedDecls.unlink(dcl)
+            erasedDecls.enter(dcl.targetName, dcl)
         val selfType1 = if cls.is(Module) then cls.sourceModule.termRef else NoType
         tp.derivedClassInfo(NoPrefix, erasedParents, erasedDecls, selfType1)
           // can't replace selftype by NoType because this would lose the sourceModule link

tests/run/i13252.scala

@@ -0,0 +1,12 @@
+object Test:
+
+  class Star
+
+  trait Foo:
+    @annotation.targetName("star")
+    val * : Star = new Star
+
+  object Bar extends Foo
+
+  def main(sa: Array[String]): Unit =
+    Bar.*

tests/run/i13252/Foo_1.scala

@@ -0,0 +1,5 @@
+class Star
+
+trait Foo:
+  @annotation.targetName("star")
+  val * : Star = new Star

tests/run/i13252/Test_2.scala

@@ -0,0 +1,6 @@
+object Test:
+
+  object Bar extends Foo
+
+  def main(sa: Array[String]): Unit =
+    Bar.*