ICU-20863 Regex Named Capture map, add a missing nullptr check.
diff --git a/icu4c/source/i18n/repattrn.cpp b/icu4c/source/i18n/repattrn.cpp
index ee6bc68..bf18695 100644
--- a/icu4c/source/i18n/repattrn.cpp
+++ b/icu4c/source/i18n/repattrn.cpp
@@ -850,7 +850,7 @@
     }
 
     printf("Named Capture Groups:\n");
-    if (uhash_count(fNamedCaptureMap) == 0) {
+    if (!fNamedCaptureMap || uhash_count(fNamedCaptureMap) == 0) {
         printf("   None\n");
     } else {
         int32_t pos = UHASH_FIRST;