diff --git a/core/compiler.common/src/org/jetbrains/kotlin/name/FqNameUnsafe.java b/core/compiler.common/src/org/jetbrains/kotlin/name/FqNameUnsafe.java
index 1c31d782b90..a47eda38547 100644
--- a/core/compiler.common/src/org/jetbrains/kotlin/name/FqNameUnsafe.java
+++ b/core/compiler.common/src/org/jetbrains/kotlin/name/FqNameUnsafe.java
@@ -163,7 +163,8 @@ public final class FqNameUnsafe {
             return false;
 
         int firstDot = fqName.indexOf('.');
-        return fqName.regionMatches(0, segment.asString(), 0, firstDot == -1 ? fqName.length() : firstDot);
+        String segmentAsString = segment.asString();
+        return fqName.regionMatches(0, segmentAsString, 0, firstDot == -1 ? Math.max(fqName.length(), segmentAsString.length()) : firstDot);
     }
 
     @NotNull