From ce702dd48cd788db1511288db24b224a79218e37 Mon Sep 17 00:00:00 2001
From: "Anna.Kozlova" <anna.kozlova@jetbrains.com>
Date: Mon, 10 Apr 2017 12:56:48 +0200
Subject: [PATCH] redundant cast: process multidimensional arrays (IDEA-171047)

---
 .../com/intellij/psi/util/RedundantCastUtil.java    | 13 ++++++++++++-
 .../lambda/CastInMultidimensionalArrayIndex.java    |  5 +++++
 .../codeInspection/RedundantCast18Test.java         |  1 +
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 java/java-tests/testData/inspection/redundantCast/lambda/CastInMultidimensionalArrayIndex.java

diff --git a/java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java b/java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java
index c02649b0fa68..b1e85b73ca6b 100644
--- a/java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java
+++ b/java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java
@@ -738,7 +738,18 @@ public class RedundantCastUtil {
       PsiExpression lExpression = assignment.getLExpression();
       return lExpression instanceof PsiArrayAccessExpression &&
              PsiTreeUtil.isAncestor(lExpression, parent, false) &&
-             !PsiTreeUtil.isAncestor(((PsiArrayAccessExpression)lExpression).getIndexExpression(), element, false);
+             !isIndexExpression(element, (PsiArrayAccessExpression)lExpression);
+    }
+
+    private static boolean isIndexExpression(PsiElement element, PsiArrayAccessExpression arrayAccessExpression) {
+      if (PsiTreeUtil.isAncestor(arrayAccessExpression.getIndexExpression(), element, false)) {
+        return true;
+      }
+      PsiExpression arrayExpression = arrayAccessExpression.getArrayExpression();
+      if (arrayExpression instanceof PsiArrayAccessExpression) {
+        return isIndexExpression(element, (PsiArrayAccessExpression)arrayExpression);
+      }
+      return false;
     }
   }
 
diff --git a/java/java-tests/testData/inspection/redundantCast/lambda/CastInMultidimensionalArrayIndex.java b/java/java-tests/testData/inspection/redundantCast/lambda/CastInMultidimensionalArrayIndex.java
new file mode 100644
index 000000000000..5e6a9c5471c0
--- /dev/null
+++ b/java/java-tests/testData/inspection/redundantCast/lambda/CastInMultidimensionalArrayIndex.java
@@ -0,0 +1,5 @@
+class MyTest {
+  void bar(Object[] update, Object[][] grid){
+    grid[(int)update[0]][1] = null;
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/codeInspection/RedundantCast18Test.java b/java/java-tests/testSrc/com/intellij/codeInspection/RedundantCast18Test.java
index f544cfa44798..d1c48111b910 100644
--- a/java/java-tests/testSrc/com/intellij/codeInspection/RedundantCast18Test.java
+++ b/java/java-tests/testSrc/com/intellij/codeInspection/RedundantCast18Test.java
@@ -41,4 +41,5 @@ public class RedundantCast18Test extends LightDaemonAnalyzerTestCase {
   public void testConditional() { doTest(); }
   public void testInferApplicabilityError() { doTest(); }
   public void testCastToRawType() { doTest(); }
+  public void testCastInMultidimensionalArrayIndex() { doTest(); }
 }
\ No newline at end of file