diff --git a/core/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java b/core/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java
index 36e7a73aa9a..3b21a3bd740 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java
@@ -473,8 +473,8 @@ public class DateFieldMapper extends FieldMapper {
 
     @Override
     protected void doMerge(Mapper mergeWith, boolean updateAllTypes) {
-        final DateFieldMapper other = (DateFieldMapper) mergeWith;
         super.doMerge(mergeWith, updateAllTypes);
+        final DateFieldMapper other = (DateFieldMapper) mergeWith;
         if (other.ignoreMalformed.explicit()) {
             this.ignoreMalformed = other.ignoreMalformed;
         }
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/DateFieldMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/DateFieldMapperTests.java
index b728c44cc65..7a4749bcb3c 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/DateFieldMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/DateFieldMapperTests.java
@@ -395,4 +395,20 @@ public class DateFieldMapperTests extends ESSingleNodeTestCase {
                 MapperService.MergeReason.MAPPING_UPDATE, randomBoolean()));
         assertThat(e.getMessage(), containsString("[mapper [release_date] has different [format] values]"));
     }
+
+    public void testMergeText() throws Exception {
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("doc")
+                .startObject("properties").startObject("date").field("type", "date").endObject()
+                .endObject().endObject().endObject().string();
+        DocumentMapper mapper = indexService.mapperService().parse("doc", new CompressedXContent(mapping), false);
+
+        String mappingUpdate = XContentFactory.jsonBuilder().startObject().startObject("doc")
+                .startObject("properties").startObject("date").field("type", "text").endObject()
+                .endObject().endObject().endObject().string();
+        DocumentMapper update = indexService.mapperService().parse("doc", new CompressedXContent(mappingUpdate), false);
+
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class,
+                () -> mapper.merge(update.mapping(), randomBoolean()));
+        assertEquals("mapper [date] of different type, current_type [date], merged_type [text]", e.getMessage());
+    }
 }