Reposition trees in erasure using source from tree

This decouples the repositioning from Inlined tree nodes

Author: nicolasstucki

compiler/src/dotty/tools/dotc/transform/Erasure.scala

@@ -603,7 +603,7 @@ object Erasure {
       if (tree.typeOpt.isRef(defn.UnitClass))
         tree.withType(tree.typeOpt)
       else if (tree.const.tag == Constants.ClazzTag)
-        clsOf(tree.const.typeValue)
+        clsOf(tree.const.typeValue).withSpan(tree.span)
       else
         super.typedLiteral(tree)
 
@@ -739,6 +739,23 @@ object Erasure {
       checkValue(checkNotErased(recur(qual1)), pt)
     }
 
+    // TODO track in a cleaner way
+    private var enclosingSpan: util.Spans.Span = util.Spans.NoSpan
+
+    override def typed(tree: untpd.Tree, pt: Type, locked: TypeVars)(using Context): Tree =
+      val old = enclosingSpan
+      enclosingSpan = tree.span
+      val tree1 =
+        try super.typed(tree, pt, locked)
+        finally enclosingSpan = old
+
+      if tree1.source.exists && ctx.source != tree1.source && ctx.source == ctx.owner.topLevelClass.source
+      then
+        // TODO reposition while erasing instead of retraversing
+        Inliner.reposition(tree1, enclosingSpan)
+      else tree1
+
+
     override def typedThis(tree: untpd.This)(using Context): Tree =
       if (tree.symbol == ctx.owner.lexicallyEnclosingClass || tree.symbol.isStaticOwner) promote(tree)
       else {

compiler/src/dotty/tools/dotc/typer/Inliner.scala

@@ -207,16 +207,13 @@ object Inliner {
 
   /** Replace `Inlined` node by a block that contains its bindings and expansion */
   def dropInlined(inlined: Inlined)(using Context): Tree =
-    val tree1 =
-      if inlined.bindings.isEmpty then inlined.expansion
-      else cpy.Block(inlined)(inlined.bindings, inlined.expansion)
-    // Reposition in the outer most inlined call
-    if (enclosingInlineds.nonEmpty) tree1 else reposition(tree1, inlined.span)
+    if inlined.bindings.isEmpty then inlined.expansion
+    else cpy.Block(inlined)(inlined.bindings, inlined.expansion)
 
   def reposition(tree: Tree, callSpan: Span)(using Context): Tree = {
     // Reference test tests/run/i4947b
 
-    val curSource = ctx.compilationUnit.source
+    val curSource = ctx.owner.topLevelClass.source
 
     // Tree copier that changes the source of all trees to `curSource`
     val cpyWithNewSource = new TypedTreeCopier {

tests/run-macros/i4947e.check

@@ -1,8 +1,8 @@
-assertImpl: Test$.main(Test_2.scala:7)
+assertImpl: Test$.main(Test_2.scala:3)
 true
-assertImpl: Test$.main(Test_2.scala:8)
+assertImpl: Test$.main(Test_2.scala:3)
 false
-assertImpl: Test$.main(Test_2.scala:9)
+assertImpl: Test$.main(Test_2.scala:3)
 hi: Test$.main(Test_2.scala:10)
 hi again: Test$.main(Test_2.scala:11)
 false