From aa94474b1cdb95ef3952da678ea5fd58175d21f3 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Mon, 26 Apr 2021 18:10:48 +0200
Subject: [PATCH 1/3] Trial: bypass compiletimeConstantFold in
 translucentSuperType

---
 .../src/dotty/tools/dotc/core/Types.scala     | 32 +++++++++++--------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index 8a0b0f12c167..a3345b939bd2 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -4016,10 +4016,13 @@ object Types {
     }
 
     override def translucentSuperType(using Context): Type = tycon match {
-      case tycon: TypeRef if tycon.symbol.isOpaqueAlias =>
-        tycon.translucentSuperType.applyIfParameterized(args)
+      case tycon: TypeRef =>
+        if tycon.symbol.isOpaqueAlias then
+          tycon.translucentSuperType.applyIfParameterized(args)
+        else
+          tryMatchAlias(tycon).orElse(superType)
       case _ =>
-        tryNormalize.orElse(superType)
+        superType
     }
 
     inline def map(inline op: Type => Type)(using Context) =
@@ -4034,19 +4037,20 @@ object Types {
         case nil => x
       foldArgs(op(x, tycon), args)
 
+    private def tryMatchAlias(tycon: TypeRef)(using Context) = tycon.info match {
+      case MatchAlias(alias) =>
+        trace(i"normalize $this", typr, show = true) {
+          MatchTypeTrace.recurseWith(this) {
+            alias.applyIfParameterized(args).tryNormalize
+          }
+        }
+      case _ =>
+        NoType
+    }
+
     override def tryNormalize(using Context): Type = tycon.stripTypeVar match {
       case tycon: TypeRef =>
-        def tryMatchAlias = tycon.info match {
-          case MatchAlias(alias) =>
-            trace(i"normalize $this", typr, show = true) {
-              MatchTypeTrace.recurseWith(this) {
-                alias.applyIfParameterized(args).tryNormalize
-              }
-            }
-          case _ =>
-            NoType
-        }
-        tryCompiletimeConstantFold.orElse(tryMatchAlias)
+        tryCompiletimeConstantFold.orElse(tryMatchAlias(tycon))
       case _ =>
         NoType
     }

From 68c95329e1ea031abe9fe45304a1260f1d18b17c Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Tue, 27 Apr 2021 09:28:12 +0200
Subject: [PATCH 2/3] Revert "Trial: bypass compiletimeConstantFold in
 translucentSuperType"

This reverts commit aa94474b1cdb95ef3952da678ea5fd58175d21f3.
---
 .../src/dotty/tools/dotc/core/Types.scala     | 32 ++++++++-----------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index a3345b939bd2..8a0b0f12c167 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -4016,13 +4016,10 @@ object Types {
     }
 
     override def translucentSuperType(using Context): Type = tycon match {
-      case tycon: TypeRef =>
-        if tycon.symbol.isOpaqueAlias then
-          tycon.translucentSuperType.applyIfParameterized(args)
-        else
-          tryMatchAlias(tycon).orElse(superType)
+      case tycon: TypeRef if tycon.symbol.isOpaqueAlias =>
+        tycon.translucentSuperType.applyIfParameterized(args)
       case _ =>
-        superType
+        tryNormalize.orElse(superType)
     }
 
     inline def map(inline op: Type => Type)(using Context) =
@@ -4037,20 +4034,19 @@ object Types {
         case nil => x
       foldArgs(op(x, tycon), args)
 
-    private def tryMatchAlias(tycon: TypeRef)(using Context) = tycon.info match {
-      case MatchAlias(alias) =>
-        trace(i"normalize $this", typr, show = true) {
-          MatchTypeTrace.recurseWith(this) {
-            alias.applyIfParameterized(args).tryNormalize
-          }
-        }
-      case _ =>
-        NoType
-    }
-
     override def tryNormalize(using Context): Type = tycon.stripTypeVar match {
       case tycon: TypeRef =>
-        tryCompiletimeConstantFold.orElse(tryMatchAlias(tycon))
+        def tryMatchAlias = tycon.info match {
+          case MatchAlias(alias) =>
+            trace(i"normalize $this", typr, show = true) {
+              MatchTypeTrace.recurseWith(this) {
+                alias.applyIfParameterized(args).tryNormalize
+              }
+            }
+          case _ =>
+            NoType
+        }
+        tryCompiletimeConstantFold.orElse(tryMatchAlias)
       case _ =>
         NoType
     }

From c0df023b46a0ad453c9938c6e4d9413c22dea938 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Tue, 27 Apr 2021 09:29:43 +0200
Subject: [PATCH 3/3] Revert translucentSuperType

---
 compiler/src/dotty/tools/dotc/core/Types.scala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index 8a0b0f12c167..c4b42fa0889f 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -4019,7 +4019,7 @@ object Types {
       case tycon: TypeRef if tycon.symbol.isOpaqueAlias =>
         tycon.translucentSuperType.applyIfParameterized(args)
       case _ =>
-        tryNormalize.orElse(superType)
+        superType
     }
 
     inline def map(inline op: Type => Type)(using Context) =