description: Used when the target of the reference has a type that is not allowed by the definition of the element. In general, this should only arise when wrangling between versions using cross-version extensions.
package_name: hl7.fhir.r5.examples
derivation: constraint
name: alternate-canonical
type: Extension
elements:
  extension: {index: 0}
  url:
    pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/alternate-canonical'}
    index: 1
  value:
    choices: [valueCanonical]
    index: 3
  valueCanonical: {type: canonical, choiceOf: value, index: 4}
package_version: 5.0.0-snapshot3
extensions: {}
class: extension
kind: complex-type
url: http://hl7.org/fhir/StructureDefinition/alternate-canonical
base: http://hl7.org/fhir/StructureDefinition/Extension
version: 5.0.0-snapshot3
required: [valueCanonical, value]