diff --git a/compiler/test/dotty/tools/dotc/CompilationTests.scala b/compiler/test/dotty/tools/dotc/CompilationTests.scala
index a0bdfa40c7d2..8356f6da14ad 100644
--- a/compiler/test/dotty/tools/dotc/CompilationTests.scala
+++ b/compiler/test/dotty/tools/dotc/CompilationTests.scala
@@ -250,7 +250,7 @@ class CompilationTests extends ParallelTesting {
       Array("-Ycheck-reentrant", "-Yemit-tasty-in-class")
     )
 
-    val libraryDirs = List(Paths.get("library/src"), Paths.get("library/src-3.x"), Paths.get("library/src-bootstrapped"))
+    val libraryDirs = List(Paths.get("library/src"), Paths.get("library/src-bootstrapped"))
     val librarySources = libraryDirs.flatMap(sources(_))
 
     val lib =
diff --git a/library/src-3.x/scala/IArray.scala b/library/src-bootstrapped/scala/IArray.scala
similarity index 100%
rename from library/src-3.x/scala/IArray.scala
rename to library/src-bootstrapped/scala/IArray.scala
diff --git a/library/src-3.x/dotty/DottyPredef.scala b/library/src/dotty/DottyPredef.scala
similarity index 100%
rename from library/src-3.x/dotty/DottyPredef.scala
rename to library/src/dotty/DottyPredef.scala
diff --git a/library/src-3.x/scala/Tuple.scala b/library/src/scala/Tuple.scala
similarity index 100%
rename from library/src-3.x/scala/Tuple.scala
rename to library/src/scala/Tuple.scala
diff --git a/library/src-3.x/scala/TupledFunction.scala b/library/src/scala/TupledFunction.scala
similarity index 100%
rename from library/src-3.x/scala/TupledFunction.scala
rename to library/src/scala/TupledFunction.scala
diff --git a/library/src-3.x/scala/compiletime/Shape.scala b/library/src/scala/compiletime/Shape.scala
similarity index 100%
rename from library/src-3.x/scala/compiletime/Shape.scala
rename to library/src/scala/compiletime/Shape.scala
diff --git a/library/src-3.x/scala/compiletime/package.scala b/library/src/scala/compiletime/package.scala
similarity index 100%
rename from library/src-3.x/scala/compiletime/package.scala
rename to library/src/scala/compiletime/package.scala
diff --git a/library/src-3.x/scala/deriving.scala b/library/src/scala/deriving.scala
similarity index 100%
rename from library/src-3.x/scala/deriving.scala
rename to library/src/scala/deriving.scala
diff --git a/library/src-3.x/scala/internal/Quoted.scala b/library/src/scala/internal/Quoted.scala
similarity index 100%
rename from library/src-3.x/scala/internal/Quoted.scala
rename to library/src/scala/internal/Quoted.scala
diff --git a/library/src-3.x/scala/internal/WithBounds.scala b/library/src/scala/internal/WithBounds.scala
similarity index 100%
rename from library/src-3.x/scala/internal/WithBounds.scala
rename to library/src/scala/internal/WithBounds.scala
diff --git a/library/src-3.x/scala/quoted/Expr.scala b/library/src/scala/quoted/Expr.scala
similarity index 100%
rename from library/src-3.x/scala/quoted/Expr.scala
rename to library/src/scala/quoted/Expr.scala
diff --git a/library/src-3.x/scala/quoted/Liftable.scala b/library/src/scala/quoted/Liftable.scala
similarity index 100%
rename from library/src-3.x/scala/quoted/Liftable.scala
rename to library/src/scala/quoted/Liftable.scala
diff --git a/library/src-3.x/scala/quoted/Type.scala b/library/src/scala/quoted/Type.scala
similarity index 100%
rename from library/src-3.x/scala/quoted/Type.scala
rename to library/src/scala/quoted/Type.scala
diff --git a/library/src-3.x/scala/quoted/matching/Bind.scala b/library/src/scala/quoted/matching/Bind.scala
similarity index 100%
rename from library/src-3.x/scala/quoted/matching/Bind.scala
rename to library/src/scala/quoted/matching/Bind.scala
diff --git a/library/src-3.x/scala/quoted/matching/Const.scala b/library/src/scala/quoted/matching/Const.scala
similarity index 100%
rename from library/src-3.x/scala/quoted/matching/Const.scala
rename to library/src/scala/quoted/matching/Const.scala
diff --git a/library/src-3.x/scala/quoted/matching/ConstSeq.scala b/library/src/scala/quoted/matching/ConstSeq.scala
similarity index 100%
rename from library/src-3.x/scala/quoted/matching/ConstSeq.scala
rename to library/src/scala/quoted/matching/ConstSeq.scala
diff --git a/library/src-3.x/scala/quoted/matching/ExprSeq.scala b/library/src/scala/quoted/matching/ExprSeq.scala
similarity index 100%
rename from library/src-3.x/scala/quoted/matching/ExprSeq.scala
rename to library/src/scala/quoted/matching/ExprSeq.scala
diff --git a/library/src-3.x/scala/runtime/DynamicTuple.scala b/library/src/scala/runtime/DynamicTuple.scala
similarity index 100%
rename from library/src-3.x/scala/runtime/DynamicTuple.scala
rename to library/src/scala/runtime/DynamicTuple.scala
diff --git a/library/src-3.x/scala/tasty/reflect/QuotedOps.scala b/library/src/scala/tasty/reflect/QuotedOps.scala
similarity index 100%
rename from library/src-3.x/scala/tasty/reflect/QuotedOps.scala
rename to library/src/scala/tasty/reflect/QuotedOps.scala
diff --git a/library/src-3.x/scala/tasty/reflect/utils/TreeUtils.scala b/library/src/scala/tasty/reflect/utils/TreeUtils.scala
similarity index 100%
rename from library/src-3.x/scala/tasty/reflect/utils/TreeUtils.scala
rename to library/src/scala/tasty/reflect/utils/TreeUtils.scala
diff --git a/library/src-3.x/scala/util/control/NonLocalReturns.scala b/library/src/scala/util/control/NonLocalReturns.scala
similarity index 100%
rename from library/src-3.x/scala/util/control/NonLocalReturns.scala
rename to library/src/scala/util/control/NonLocalReturns.scala
diff --git a/project/Build.scala b/project/Build.scala
index 6254741bb120..d31856935194 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -708,28 +708,15 @@ object Build {
     // Needed so that the library sources are visible when `dotty.tools.dotc.core.Definitions#init` is called
     scalacOptions in Compile ++= Seq("-sourcepath", (scalaSource in Compile).value.getAbsolutePath),
 
-    // To be removed once we stop cross-compiling with Scala 2
-    unmanagedSourceDirectories in Compile += {
-      val baseDir = baseDirectory.value
-      if (!isDotty.value)
-        baseDir / "src-2.x"
-      else
-        baseDir / "src-3.x"
-    },
-
     // Add version-specific source directories:
     // - files in src-non-bootstrapped will only be compiled by the reference compiler
     // - files in src-bootstrapped will only be compiled by the current dotty compiler (non-bootstrapped and bootstrapped)
     unmanagedSourceDirectories in Compile ++= {
       val baseDir = baseDirectory.value
-      if (isDotty.value) {
-        if (scalaVersion.value == referenceVersion)
-          Seq(baseDir / "src-non-bootstrapped")
-        else
-          Seq(baseDir / "src-bootstrapped")
-      }
+      if (scalaVersion.value == referenceVersion)
+        Seq(baseDir / "src-non-bootstrapped")
       else
-        Seq()
+        Seq(baseDir / "src-bootstrapped")
     }
   )