–– Pkl Error ––
Type constraint `firstOneIsSandy` violated.
Value: new Listing { new Bird { name = "Bob" }; new Bird { name = ? } }

x | birds: Listing(firstOneIsSandy) = new {
                   ^^^^^^^^^^^^^^^
at constraintDetails1#birds (file:///$snippetsDir/input/errors/constraintDetails1.pkl)

x | birds: Listing(firstOneIsSandy) = new {
                                      ^^^^^
at constraintDetails1#birds (file:///$snippetsDir/input/errors/constraintDetails1.pkl)

xxx | renderer.renderDocument(value)
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
at pkl.base#Module.output.text (pkl:base)

xxx | if (renderer is BytesRenderer) renderer.renderDocument(value) else text.encodeToBytes("UTF-8")
                                                                         ^^^^
at pkl.base#Module.output.bytes (pkl:base)
