diff --git a/llvm/lib/Support/YAMLParser.cpp b/llvm/lib/Support/YAMLParser.cpp
--- a/llvm/lib/Support/YAMLParser.cpp
+++ b/llvm/lib/Support/YAMLParser.cpp
@@ -1423,7 +1423,7 @@
     ++Column;
   }
 
-  if (Start == Current) {
+  if (Start + 1 == Current) {
     setError("Got empty alias or anchor", Start);
     return false;
   }
diff --git a/llvm/unittests/Support/YAMLIOTest.cpp b/llvm/unittests/Support/YAMLIOTest.cpp
--- a/llvm/unittests/Support/YAMLIOTest.cpp
+++ b/llvm/unittests/Support/YAMLIOTest.cpp
@@ -3101,3 +3101,15 @@
   EXPECT_FALSE(yin2.setCurrentDocument());
   EXPECT_TRUE(yin2.error());
 }
+
+TEST(YAMLIO, TestEmptyAlias) {
+  Input yin("&");
+  EXPECT_FALSE(yin.setCurrentDocument());
+  EXPECT_TRUE(yin.error());
+}
+
+TEST(YAMLIO, TestEmptyAnchor) {
+  Input yin("*");
+  EXPECT_FALSE(yin.setCurrentDocument());
+  EXPECT_TRUE(yin.error());
+}