Fix #8865: Add regression test

Author: nicolasstucki

tests/neg-macros/i8865.scala

@@ -0,0 +1,10 @@
+import scala.quoted._
+object Macro {
+
+  def impl[A : Type](using Quotes): Expr[A] = {
+    import quotes.reflect._
+    val tpe = TypeRepr.of[A].asType
+    '{ (a: ${tpe}) => ???} // error: tpe.Underlying cannot be used as a value type
+    '{???}
+  }
+}

tests/pos-macros/i8865.scala

@@ -0,0 +1,10 @@
+import scala.quoted._
+object Macro {
+
+  def impl[A : Type](using Quotes): Expr[A] = {
+    import quotes.reflect._
+    TypeRepr.of[A].asType match
+      case '[tpe] => '{ (a: tpe) => ???}
+    '{???}
+  }
+}