Update docs/_spec/TODOreference/metaprogramming/reflection.md

Co-authored-by: Jamie Thompson <[email protected]>
[Cherry-picked 2c7d497]

Author: som-snytt

Diff for: docs/_spec/TODOreference/metaprogramming/reflection.md

@@ -82,7 +82,8 @@ def macroImpl()(quotes: Quotes): Expr[Unit] =
   import quotes.reflect.*
   val pos = Position.ofMacroExpansion
 
-  val path = pos.sourceFile.path
+  val jpath = pos.sourceFile.getJPath.getOrElse(report.errorAndAbort("virtual file not supported", pos))
+  val path = pos.sourceFile.path // fallback for a virtual file
   val start = pos.start
   val end = pos.end
   val startLine = pos.startLine