Fix using of wrong period for creating nested ctx in TreeTransforms

src/dotty/tools/dotc/transform/TreeTransform.scala

@@ -875,11 +875,13 @@ object TreeTransforms {
       }
 
     final private[TreeTransforms] def transformSingle(tree: Tree, cur: Int)(implicit ctx: Context, info: TransformerInfo): Tree =
-      tree match {
-        // split one big match into 2 smaller ones
-        case tree: NameTree => goNamed(tree, cur)
-        case tree => goUnamed(tree, cur)
-      }
+      if (cur < info.transformers.length) {
+        tree match {
+          // split one big match into 2 smaller ones
+          case tree: NameTree => goNamed(tree, cur)
+          case tree => goUnamed(tree, cur)
+        }
+      } else tree
 
     def localContext(owner: Symbol)(implicit ctx: Context) = ctx.fresh.setOwner(owner)
 
@@ -1127,11 +1129,16 @@ object TreeTransforms {
       }
 
     def transform(tree: Tree, info: TransformerInfo, cur: Int)(implicit ctx: Context): Tree = ctx.traceIndented(s"transforming ${tree.show} at ${ctx.phase}", transforms, show = true) {
-      tree match {
-        //split one big match into 2 smaller ones
-        case tree: NameTree => transformNamed(tree, info, cur)
-        case tree => transformUnnamed(tree, info, cur)
-      }
+      if (cur < info.transformers.length) {
+        // if cur > 0 then some of the symbols can be created by already performed transformations
+        // this means that their denotations could not exists in previous periods
+        val pctx = ctx.withPhase(info.transformers(cur))
+        tree match {
+          //split one big match into 2 smaller ones
+          case tree: NameTree => transformNamed(tree, info, cur)(pctx)
+          case tree => transformUnnamed(tree, info, cur)(pctx)
+        }
+      } else tree
     }
 
     @tailrec

test/test/DottyTest.scala

@@ -42,6 +42,7 @@ class DottyTest extends ContextEscapeDetection{
     ctx = null
   }
   private def compilerWithChecker(phase: String)(assertion:(tpd.Tree, Context) => Unit) = new Compiler {
+    self =>
     override def phases = {
       val allPhases = super.phases
       val targetPhase = allPhases.flatten.find(p => p.name == phase).get

test/test/transform/CreateCompanionObjectsTest.scala

@@ -32,6 +32,7 @@ class CreateCompanionObjectsTest extends DottyTest {
 
           override def name: String = "create all companion objects"
           override def predicate(cts: TypeDef)(implicit ctx:Context): Boolean = true
+          init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
         })
 
         override def name: String = "test"
@@ -56,6 +57,7 @@ class CreateCompanionObjectsTest extends DottyTest {
 
           override def name: String = "create all companion modules"
           override def predicate(cts: TypeDef)(implicit ctx:Context): Boolean = true
+          init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
         })
 
         override def name: String = "test"
@@ -79,6 +81,7 @@ class CreateCompanionObjectsTest extends DottyTest {
         override def transformations = Array(new CreateCompanionObjects {
           override def name: String = "create all companion modules"
           override def predicate(cts: TypeDef)(implicit ctx:Context): Boolean = true
+          init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
         })
 
         override def name: String = "test"
@@ -102,6 +105,7 @@ class CreateCompanionObjectsTest extends DottyTest {
         override def transformations = Array(new CreateCompanionObjects {
           override def name: String = "create all companion modules"
           override def predicate(cts: TypeDef)(implicit ctx:Context): Boolean = cts.name.toString.contains("CREATE")
+          init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
         })
 
         override def name: String = "test"

test/test/transform/PostTyperTransformerTest.scala

@@ -24,6 +24,7 @@ class PostTyperTransformerTest extends DottyTest {
       implicit val ctx = context
       class EmptyTransform extends TreeTransform {
         override def name: String = "empty"
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new PostTyperTransformer {
         override def transformations = Array(new EmptyTransform)
@@ -43,6 +44,7 @@ class PostTyperTransformerTest extends DottyTest {
       implicit val ctx = context
       class EmptyTransform extends TreeTransform {
         override def name: String = "empty"
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new PostTyperTransformer {
         override def transformations = Array(new EmptyTransform)
@@ -62,6 +64,7 @@ class PostTyperTransformerTest extends DottyTest {
       implicit val ctx = context
       class EmptyTransform extends TreeTransform {
         override def name: String = "empty"
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new PostTyperTransformer {
         override def transformations = Array(new EmptyTransform)
@@ -85,6 +88,7 @@ class PostTyperTransformerTest extends DottyTest {
       implicit val ctx = context
       class EmptyTransform extends TreeTransform {
         override def name: String = "empty"
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new PostTyperTransformer {
         override def transformations = Array(new EmptyTransform)
@@ -108,6 +112,7 @@ class PostTyperTransformerTest extends DottyTest {
       implicit val ctx = context
       class EmptyTransform extends TreeTransform {
         override def name: String = "empty"
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new PostTyperTransformer {
         override def transformations = Array(new EmptyTransform)

test/test/transform/TreeTransformerTest.scala

@@ -17,6 +17,7 @@ class TreeTransformerTest extends DottyTest {
       implicit val ctx = context
       class EmptyTransform extends TreeTransform {
         override def name: String = "empty"
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new TreeTransformer {
         override def transformations = Array(new EmptyTransform)
@@ -38,6 +39,7 @@ class TreeTransformerTest extends DottyTest {
 
         override def transformLiteral(tree: tpd.Literal)(implicit ctx: Context, info: TransformerInfo): tpd.Tree = tpd.Literal(Constant(2))
         override def name: String = "canReplaceConstant"
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new TreeTransformer {
         override def transformations = Array(new ConstantTransform)
@@ -66,11 +68,14 @@ class TreeTransformerTest extends DottyTest {
           )
           tpd.cpy.ValDef(tree, tree.mods, tree.name, tree.tpt, tpd.Literal(Constant(2)))
         }
+
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new TreeTransformer {
         override def transformations = Array(new Transformation)
 
         override def name: String = "test"
+
       }
       val tr = transformer.transform(tree).toString
 
@@ -99,6 +104,8 @@ class TreeTransformerTest extends DottyTest {
           )
           tpd.cpy.ValDef(tree, tree.mods, tree.name, tree.tpt, tpd.Literal(Constant(2)))
         }
+
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       class Transformation2 extends TreeTransform {
         override def name: String = "transformationOrder2"
@@ -108,6 +115,8 @@ class TreeTransformerTest extends DottyTest {
           )
           tpd.cpy.ValDef(tree, tree.mods, tree.name, tree.tpt, tpd.Literal(Constant(3)))
         }
+
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new TreeTransformer {
         override def transformations = Array(new Transformation1, new Transformation2)
@@ -143,6 +152,8 @@ class TreeTransformerTest extends DottyTest {
           )
           tpd.cpy.ValDef(tree, tree.mods, tree.name, tree.tpt, transformFollowing(tpd.Literal(Constant(2))))
         }
+
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       var transformed2 = 0
       class Transformation2 extends TreeTransform {
@@ -172,6 +183,8 @@ class TreeTransformerTest extends DottyTest {
           )
           transformFollowing(tpd.cpy.ValDef(tree, tree.mods, tree.name, tree.tpt, tpd.Literal(Constant(3))))
         }
+
+        init(ctx, ctx.period.firstPhaseId, ctx.period.lastPhaseId)
       }
       val transformer = new TreeTransformer {
         override def transformations = Array(new Transformation1, new Transformation2)