From 3f1b86f5fd92da2a3808ab25464b0f838f07335f Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Sat, 7 Aug 2021 21:17:53 +0200
Subject: [PATCH 1/2] Enter symbols under their target names after erasure

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

Fixes #13252
---
 compiler/src/dotty/tools/dotc/core/Scopes.scala      | 12 ++++++------
 compiler/src/dotty/tools/dotc/core/TypeErasure.scala |  9 ++++++++-
 tests/run/i13252.scala                               | 12 ++++++++++++
 tests/run/i13252/Foo_1.scala                         |  5 +++++
 tests/run/i13252/Test_2.scala                        |  6 ++++++
 5 files changed, 37 insertions(+), 7 deletions(-)
 create mode 100644 tests/run/i13252.scala
 create mode 100644 tests/run/i13252/Foo_1.scala
 create mode 100644 tests/run/i13252/Test_2.scala

diff --git a/compiler/src/dotty/tools/dotc/core/Scopes.scala b/compiler/src/dotty/tools/dotc/core/Scopes.scala
index cb5f5c55e337..b22ce84849c1 100644
--- a/compiler/src/dotty/tools/dotc/core/Scopes.scala
+++ b/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
     }
diff --git a/compiler/src/dotty/tools/dotc/core/TypeErasure.scala b/compiler/src/dotty/tools/dotc/core/TypeErasure.scala
index 3a077407d0b5..7e89b4e2c2c9 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeErasure.scala
+++ b/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
diff --git a/tests/run/i13252.scala b/tests/run/i13252.scala
new file mode 100644
index 000000000000..d12706f62a95
--- /dev/null
+++ b/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.*
\ No newline at end of file
diff --git a/tests/run/i13252/Foo_1.scala b/tests/run/i13252/Foo_1.scala
new file mode 100644
index 000000000000..7e7551e14f4c
--- /dev/null
+++ b/tests/run/i13252/Foo_1.scala
@@ -0,0 +1,5 @@
+class Star
+
+trait Foo:
+  @annotation.targetName("star")
+  val * : Star = new Star
diff --git a/tests/run/i13252/Test_2.scala b/tests/run/i13252/Test_2.scala
new file mode 100644
index 000000000000..b4d382d2cc1f
--- /dev/null
+++ b/tests/run/i13252/Test_2.scala
@@ -0,0 +1,6 @@
+object Test:
+
+  object Bar extends Foo
+
+  def main(sa: Array[String]): Unit =
+    Bar.*
\ No newline at end of file

From 7934075b5847de95b698f33efb64da0f4a76b3d1 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Fri, 13 Aug 2021 15:13:09 +0200
Subject: [PATCH 2/2] Address review comment

---
 tests/run/{i13252.scala => i13252a.scala}  | 0
 tests/run/{i13252 => i13252b}/Foo_1.scala  | 0
 tests/run/{i13252 => i13252b}/Test_2.scala | 0
 3 files changed, 0 insertions(+), 0 deletions(-)
 rename tests/run/{i13252.scala => i13252a.scala} (100%)
 rename tests/run/{i13252 => i13252b}/Foo_1.scala (100%)
 rename tests/run/{i13252 => i13252b}/Test_2.scala (100%)

diff --git a/tests/run/i13252.scala b/tests/run/i13252a.scala
similarity index 100%
rename from tests/run/i13252.scala
rename to tests/run/i13252a.scala
diff --git a/tests/run/i13252/Foo_1.scala b/tests/run/i13252b/Foo_1.scala
similarity index 100%
rename from tests/run/i13252/Foo_1.scala
rename to tests/run/i13252b/Foo_1.scala
diff --git a/tests/run/i13252/Test_2.scala b/tests/run/i13252b/Test_2.scala
similarity index 100%
rename from tests/run/i13252/Test_2.scala
rename to tests/run/i13252b/Test_2.scala