Merge pull request #464 from scala/backport-lts-3.3-23358

Backport "bugfix: Check for error before checking members of product type in getUnapplySelectors" to 3.3 LTS

Author: tgodzik

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

@@ -124,8 +124,11 @@ object Applications {
   }
 
   def productSelectorTypes(tp: Type, errorPos: SrcPos)(using Context): List[Type] = {
-    val sels = for (n <- Iterator.from(0)) yield extractorMemberType(tp, nme.selectorName(n), errorPos)
-    sels.takeWhile(_.exists).toList
+    if tp.isError then
+      Nil
+    else
+      val sels = for (n <- Iterator.from(0)) yield extractorMemberType(tp, nme.selectorName(n), errorPos)
+      sels.takeWhile(_.exists).toList
   }
 
   def tupleComponentTypes(tp: Type)(using Context): List[Type] =

tests/neg/i23156.scala

@@ -0,0 +1,6 @@
+object Unpack {
+  (1, 2) match {
+    case Unpack(first, _) => first
+  }
+  def unapply(e: (Int, Int)): Option[T] = ??? // error
+}