Do not crash when typing a closure with unknown type, since it can occur for erroneous input

Author: KacperFKorban

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

@@ -1722,8 +1722,6 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
                   EmptyTree
             }
           case tp =>
-            if !tp.isErroneous then
-              throw new java.lang.Error(i"internal error: closing over non-method $tp, pos = ${tree.span}")
             TypeTree(defn.AnyType)
         }
       else typed(tree.tpt)

tests/neg/i20511-1.scala

@@ -0,0 +1,7 @@
+package pakiet
+
+def toppingPrice(size: Int): Double = ???
+
+def crustPrice(crustType: Double): Double = ???
+
+export toppingPrice.apply, crustPrice.unlift // error // error // error

tests/neg/i20511.scala

@@ -0,0 +1,8 @@
+package pakiet
+
+def toppingPrice(size: Int): Double = ???
+
+def crustPrice(crustType: Double): Double = ???
+
+export toppingPrice, crustPrice // error // error
+val i = 1 // error