From 4a79dbe0102068bc7c0be0bb8b3db6a7d49511c0 Mon Sep 17 00:00:00 2001
From: Tagir Valeev <Tagir.Valeev@jetbrains.com>
Date: Wed, 14 Jun 2017 10:07:30 +0700
Subject: [PATCH] StatementExtractor: better diagnostics if parent is
 unexpectedly null

Review: IDEA-CR-21189
---
 .../src/com/siyeh/ig/psiutils/StatementExtractor.java        | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/StatementExtractor.java b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/StatementExtractor.java
index c2e917d42179..82af144cd8b4 100644
--- a/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/StatementExtractor.java
+++ b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/psiutils/StatementExtractor.java
@@ -73,7 +73,10 @@ public class StatementExtractor {
       }
       parent = ObjectUtils.tryCast(parentElement, PsiExpression.class);
       if (parent == null) {
-        throw new RuntimeExceptionWithAttachments("Expected to have expression parent",
+        String message = PsiTreeUtil.isAncestor(root, expression, false) ?
+                         "Expected to have expression parent" :
+                         "Supplied root is not the expression ancestor";
+        throw new RuntimeExceptionWithAttachments(message,
                                                   new Attachment("expression.txt", expression.getText()),
                                                   new Attachment("root.txt", root.getText()));
       }