diff --git a/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java b/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
index 486951ead5..c8cac49848 100644
--- a/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
+++ b/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
@@ -189,7 +189,7 @@ private static String translated(final Train<Shift> train, final XML xmir) throw
      * Exception which indicates that translation to phi can't be processed.
      * @since 0.36.0
      */
-    static class ImpossibleToPhiTranslationException extends Exception {
+    private static class ImpossibleToPhiTranslationException extends Exception {
         /**
          * Ctor.
          * @param cause Cause of the exception.