From 73a8a6e05144d0ef759d573d146f6b6c2cbca66f Mon Sep 17 00:00:00 2001
From: Fengyun Liu <fengyun.liu.cs@gmail.com>
Date: Wed, 30 Nov 2022 22:38:01 +0100
Subject: [PATCH] Fix #16438: Ignore erroneous parent call in init check

---
 .../src/dotty/tools/dotc/transform/init/Semantic.scala | 10 +++++++---
 tests/neg/i16438.scala                                 |  4 ++++
 2 files changed, 11 insertions(+), 3 deletions(-)
 create mode 100644 tests/neg/i16438.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala b/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala
index a48aa77fe79f..10eb28943770 100644
--- a/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala
+++ b/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala
@@ -1663,9 +1663,13 @@ object Semantic:
           // term arguments to B. That can only be done in a concrete class.
           val tref = typeRefOf(klass.typeRef.baseType(mixin).typeConstructor)
           val ctor = tref.classSymbol.primaryConstructor
-          if ctor.exists then extendTrace(superParent) {
-            superCall(tref, ctor, Nil, tasks)
-          }
+          if ctor.exists && ctor.paramSymss.isEmpty then
+            // The parameter check of traits comes late in the mixin phase.
+            // To avoid crash we ignore the initialization check for erroneous
+            // parent call code. See tests/neg/i16438.scala.
+            extendTrace(superParent) {
+              superCall(tref, ctor, args = Nil, tasks)
+            }
       }
 
       // initialize super classes after outers are set
diff --git a/tests/neg/i16438.scala b/tests/neg/i16438.scala
new file mode 100644
index 000000000000..33873b13384b
--- /dev/null
+++ b/tests/neg/i16438.scala
@@ -0,0 +1,4 @@
+// scalac: -Ysafe-init
+trait ATrait(val string: String, val int: Int)
+trait AnotherTrait( override val string: String, override val int: Int) extends ATrait
+case class ACaseClass(override val string: String) extends AnotherTrait(string, 3) // error