From ca49f980a8119fb968f94abea44f1455f02c0d80 Mon Sep 17 00:00:00 2001
From: Oleg Shpynov <oleg.shpynov@jetbrains.com>
Date: Tue, 2 Mar 2010 18:59:31 +0300
Subject: [PATCH] PY-623 "Unused assignment" false positive

---
 .../codeInsight/controlflow/PyControlFlowBuilder.java  | 10 ++++++++++
 .../src/com/jetbrains/python/psi/PyElementVisitor.java |  5 +++++
 .../python/psi/impl/PyAssignmentStatementImpl.java     |  2 +-
 .../python/psi/impl/PySubscriptionExpressionImpl.java  |  6 ++++++
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/python/src/com/jetbrains/python/codeInsight/controlflow/PyControlFlowBuilder.java b/python/src/com/jetbrains/python/codeInsight/controlflow/PyControlFlowBuilder.java
index 8023a028b79a..c3bef81d1274 100644
--- a/python/src/com/jetbrains/python/codeInsight/controlflow/PyControlFlowBuilder.java
+++ b/python/src/com/jetbrains/python/codeInsight/controlflow/PyControlFlowBuilder.java
@@ -47,6 +47,16 @@ public class PyControlFlowBuilder extends PyRecursiveElementVisitor {
     super.visitPyStatement(node);
   }
 
+  @Override
+  public void visitPySubscriptionExpression(PySubscriptionExpression node) {
+    myBuilder.startNode(node);
+    node.getOperand().accept(this);
+    final PyExpression expression = node.getIndexExpression();
+    if (expression != null) {
+      expression.accept(this);
+    }
+  }
+
   @Override
   public void visitPyReferenceExpression(final PyReferenceExpression node) {
     final PyExpression qualifier = node.getQualifier();
diff --git a/python/src/com/jetbrains/python/psi/PyElementVisitor.java b/python/src/com/jetbrains/python/psi/PyElementVisitor.java
index 8084c465cc7e..16610afc596d 100644
--- a/python/src/com/jetbrains/python/psi/PyElementVisitor.java
+++ b/python/src/com/jetbrains/python/psi/PyElementVisitor.java
@@ -17,6 +17,7 @@
 package com.jetbrains.python.psi;
 
 import com.intellij.psi.PsiElementVisitor;
+import com.jetbrains.python.psi.impl.PySubscriptionExpressionImpl;
 
 /**
  * Visitor for python-specific nodes.
@@ -225,4 +226,8 @@ public class PyElementVisitor extends PsiElementVisitor {
   public void visitPyStarExpression(PyStarExpression node) {
     visitPyExpression(node);
   }
+
+  public void visitPySubscriptionExpression(PySubscriptionExpression node) {
+    visitPyExpression(node);
+  }
 }
diff --git a/python/src/com/jetbrains/python/psi/impl/PyAssignmentStatementImpl.java b/python/src/com/jetbrains/python/psi/impl/PyAssignmentStatementImpl.java
index 8a4fd18a3b5b..18bb6fc6f60e 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyAssignmentStatementImpl.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyAssignmentStatementImpl.java
@@ -58,7 +58,7 @@ public class PyAssignmentStatementImpl extends PyElementImpl implements PyAssign
     List<PyExpression> candidates = PyUtil.flattenedParens(psi_nodes); // put all possible tuples to one level
     List<PyExpression> targets = new ArrayList<PyExpression>();
     for (PyExpression expr : candidates) { // only filter out targets
-      if (expr instanceof PyTargetExpression) {
+      if (expr instanceof PyTargetExpression || expr instanceof PySubscriptionExpression) {
         targets.add(expr);
       }
     }
diff --git a/python/src/com/jetbrains/python/psi/impl/PySubscriptionExpressionImpl.java b/python/src/com/jetbrains/python/psi/impl/PySubscriptionExpressionImpl.java
index aa1765f6c614..7a31d67f7e5e 100644
--- a/python/src/com/jetbrains/python/psi/impl/PySubscriptionExpressionImpl.java
+++ b/python/src/com/jetbrains/python/psi/impl/PySubscriptionExpressionImpl.java
@@ -18,6 +18,7 @@ package com.jetbrains.python.psi.impl;
 
 import com.intellij.lang.ASTNode;
 import com.jetbrains.python.PyElementTypes;
+import com.jetbrains.python.psi.PyElementVisitor;
 import com.jetbrains.python.psi.PyExpression;
 import com.jetbrains.python.psi.PySubscriptionExpression;
 import com.jetbrains.python.psi.types.PyType;
@@ -44,6 +45,11 @@ public class PySubscriptionExpressionImpl extends PyElementImpl implements PySub
     return childToPsi(PyElementTypes.EXPRESSIONS, 1);
   }
 
+  @Override
+  protected void acceptPyVisitor(final PyElementVisitor pyVisitor) {
+    pyVisitor.visitPySubscriptionExpression(this);
+  }
+
   public PyType getType() {
     return null;
   }