From 0114f790a47b543feb4ffe47187fb3adcfae8aa7 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Mon, 6 Dec 2021 18:51:34 +0100
Subject: [PATCH] Handle hoisted super arguments correctly in elimByName

Fixes #14010
---
 .../tools/dotc/transform/HoistSuperArgs.scala |  2 +-
 .../dotc/transform/TransformByNameApply.scala |  6 ++-
 tests/pos/i14010.scala                        | 46 +++++++++++++++++++
 tests/pos/i14010a.scala                       |  3 ++
 4 files changed, 54 insertions(+), 3 deletions(-)
 create mode 100644 tests/pos/i14010.scala
 create mode 100644 tests/pos/i14010a.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/HoistSuperArgs.scala b/compiler/src/dotty/tools/dotc/transform/HoistSuperArgs.scala
index ca584561b711..e1bcc7e6a9b4 100644
--- a/compiler/src/dotty/tools/dotc/transform/HoistSuperArgs.scala
+++ b/compiler/src/dotty/tools/dotc/transform/HoistSuperArgs.scala
@@ -88,7 +88,7 @@ class HoistSuperArgs extends MiniPhase with IdentityDenotTransformer { thisPhase
       def newSuperArgMethod(argType: Type) = {
         val (staticFlag, methOwner) =
           if (cls.owner.is(Package)) (JavaStatic, cls) else (EmptyFlags, cls.owner)
-        val argTypeWrtConstr = argType.subst(origParams, allParamRefs(constr.info))
+        val argTypeWrtConstr = argType.widenTermRefExpr.subst(origParams, allParamRefs(constr.info))
         // argType with references to paramRefs of the primary constructor instead of
         // local parameter accessors
         newSymbol(
diff --git a/compiler/src/dotty/tools/dotc/transform/TransformByNameApply.scala b/compiler/src/dotty/tools/dotc/transform/TransformByNameApply.scala
index af0998293904..9eb9b3f0ad5a 100644
--- a/compiler/src/dotty/tools/dotc/transform/TransformByNameApply.scala
+++ b/compiler/src/dotty/tools/dotc/transform/TransformByNameApply.scala
@@ -11,7 +11,8 @@ import Types._
 import Flags._
 import Decorators._
 import DenotTransformers._
-import core.StdNames.nme
+import StdNames.nme
+import NameKinds.SuperArgName
 import ast.Trees._
 import reporting.trace
 
@@ -51,7 +52,8 @@ abstract class TransformByNameApply extends MiniPhase { thisPhase: DenotTransfor
             if qual.tpe.derivesFrom(defn.Function0) && (isPureExpr(qual) || qual.symbol.isAllOf(Inline | Param)) =>
               wrap(qual)
             case _ =>
-              if (isByNameRef(arg) || arg.symbol == defn.cbnArg) arg
+              if isByNameRef(arg) || arg.symbol == defn.cbnArg || arg.symbol.name.is(SuperArgName)
+              then arg
               else wrap(mkByNameClosure(arg, argType))
           }
         case _ =>
diff --git a/tests/pos/i14010.scala b/tests/pos/i14010.scala
new file mode 100644
index 000000000000..a881f783f39b
--- /dev/null
+++ b/tests/pos/i14010.scala
@@ -0,0 +1,46 @@
+abstract class LazyList[+T] {
+  def head: T
+  def tail: LazyList[T]
+  def isEmpty: Boolean
+  def push[E >: T](top: => E): LazyList[E] =
+    new Push[E](top, this)
+  //def map[R](f: T => R): LazyList[R]
+  def append[E >: T](that: => LazyList[E]): LazyList[E]
+}
+
+private class Push[+T](top: => T, stack: => LazyList[T]) extends LazyList[T] {
+  override def head: T =
+    top
+  override def tail: LazyList[T] =
+    stack
+  override def isEmpty: Boolean =
+    false
+  //override def map[R](f: T => R): LazyList[R] =
+  //  new Push[R](f(top), stack.map(f)) {
+  //        override def map[R2](f2: R => R2): LazyList[R2] =
+  //          Push.this.map(f2 compose f)
+  //      }
+  override def append[E >: T](that: => LazyList[E]): LazyList[E] =
+    new Push[E](top, stack.append(that)) {
+          override def append[E2 >: E](that2: => LazyList[E2]): LazyList[E2] =
+            Push.this.append(that.append(that2))
+        }
+}
+
+object LazyList {
+  val empty =
+    new LazyList[Nothing] {
+          override def head: Nothing =
+            throw new NoSuchElementException
+          override def tail: LazyList[Nothing] =
+            throw new UnsupportedOperationException
+          override def isEmpty: Boolean =
+            true
+          //override def map[R](f: _ => R): LazyList[R] =
+          //  this
+          override def append[E](that: => LazyList[E]): LazyList[E] =
+            that
+        }
+  def apply[T](elements: T*): LazyList[T] =
+    elements.foldRight[LazyList[T]](empty)(new Push(_, _))
+}
\ No newline at end of file
diff --git a/tests/pos/i14010a.scala b/tests/pos/i14010a.scala
new file mode 100644
index 000000000000..5e77f55fdf62
--- /dev/null
+++ b/tests/pos/i14010a.scala
@@ -0,0 +1,3 @@
+class Foo(top: => Int) {
+  def foo: Any = new Foo(top) { }
+}
\ No newline at end of file