From dadda110d2664e1768d8f649190a6ea5addac6c2 Mon Sep 17 00:00:00 2001
From: Grahame Grieve <grahameg@gmail.com>
Date: Thu, 10 Feb 2022 11:19:52 +1100
Subject: [PATCH] fix validation of bindings on choice types - only consider
 bindable types

---
 .../type/StructureDefinitionValidator.java        | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
index 8e9b7eced..b623469f9 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
@@ -211,7 +211,10 @@ public class StructureDefinitionValidator extends BaseValidator {
 
   private void validateBinding(List<ValidationMessage> errors, Element binding, NodeStack stack, Set<String> typeCodes, boolean snapshot, String path) {
     rule(errors, IssueType.BUSINESSRULE, stack.getLiteralPath(), !snapshot || bindableType(typeCodes) != null, I18nConstants.SD_ED_BIND_NO_BINDABLE, path, typeCodes.toString());
-    hint(errors, IssueType.BUSINESSRULE, stack.getLiteralPath(), typeCodes.size() <= 1, I18nConstants.SD_ED_BIND_MULTIPLE_TYPES, path, typeCodes.toString());
+    if (!snapshot) {
+      Set<String> bindables = getListofBindableTypes(typeCodes);    
+      hint(errors, IssueType.BUSINESSRULE, stack.getLiteralPath(), bindables.size() <= 1, I18nConstants.SD_ED_BIND_MULTIPLE_TYPES, path, typeCodes.toString());
+    }
     
     if (binding.hasChild("valueSet")) {
       Element valueSet = binding.getNamedChild("valueSet");
@@ -230,6 +233,16 @@ public class StructureDefinitionValidator extends BaseValidator {
     } 
   }
 
+  private Set<String> getListofBindableTypes(Set<String> types) {
+    Set<String> res = new HashSet<>();
+    for (String s : types) {
+      if (Utilities.existsInList(s, "code", "string", "url", "uri", "Coding", "CodeableConcept", "Quantity", "CodeableReference")) {
+        res.add(s);
+      }
+    }
+    return res;
+  }
+
   private boolean serverSupportsValueSet(String ref) {
     ValidationResult vr = context.validateCode(new ValidationOptions().checkValueSetOnly().setVsAsUrl().noClient(), new Coding("http://loinc.org", "5792-7", null), new ValueSet().setUrl(ref));
     return vr.getErrorClass() == null;