Fix #5547: Add regression test

The preciseness of the error message was already improved in #6804.

Author: nicolasstucki

tests/pos/i5547.scala

@@ -0,0 +1,12 @@
+import scala.quoted._
+
+object scalatest {
+  inline def assert1(condition: => Boolean): Unit =
+   ${assertImpl('condition, '{""})}
+
+  inline def assert2(condition: => Boolean): Unit =
+    ${ assertImpl('condition, "".toExpr) }
+
+  def assertImpl(condition: Expr[Boolean], clue: Expr[Any]) given QuoteContext: Expr[Unit] =
+    '{}
+}