diff --git a/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DataFlowAnalyzer.java b/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DataFlowAnalyzer.java
index 80d6adf55d4..b805fcc9ec2 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DataFlowAnalyzer.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DataFlowAnalyzer.java
@@ -85,8 +85,11 @@ public class DataFlowAnalyzer {
                     DataFlowInfo dataFlowInfo = extractDataFlowInfoFromCondition(expression.getLeft(), conditionValue, context);
                     KtExpression expressionRight = expression.getRight();
                     if (expressionRight != null) {
-                        DataFlowInfo rightInfo = extractDataFlowInfoFromCondition(expressionRight, conditionValue, context);
                         boolean and = operationToken == KtTokens.ANDAND;
+                        DataFlowInfo rightInfo = extractDataFlowInfoFromCondition(
+                                expressionRight, conditionValue,
+                                and == conditionValue ? context.replaceDataFlowInfo(dataFlowInfo) : context
+                        );
                         if (and == conditionValue) { // this means: and && conditionValue || !and && !conditionValue
                             dataFlowInfo = dataFlowInfo.and(rightInfo);
                         }
diff --git a/compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.kt b/compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.kt
new file mode 100644
index 00000000000..c797a019214
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.kt
@@ -0,0 +1,38 @@
+fun foo(x : String?, y : String?) {
+    if (y != null && x == y) {
+        // Both not null
+        <!DEBUG_INFO_SMARTCAST!>x<!>.length
+        <!DEBUG_INFO_SMARTCAST!>y<!>.length
+    }
+    else {
+        x<!UNSAFE_CALL!>.<!>length
+        y<!UNSAFE_CALL!>.<!>length
+    }
+    if (y != null || x == y) {
+        x<!UNSAFE_CALL!>.<!>length
+        y<!UNSAFE_CALL!>.<!>length
+    }
+    else {
+        // y == null but x != y
+        <!DEBUG_INFO_SMARTCAST!>x<!>.length
+        y<!UNSAFE_CALL!>.<!>length
+    }
+    if (y == null && x != y) {
+        // y == null but x != y
+        <!DEBUG_INFO_SMARTCAST!>x<!>.length
+        y<!UNSAFE_CALL!>.<!>length
+    }
+    else {
+        x<!UNSAFE_CALL!>.<!>length
+        y<!UNSAFE_CALL!>.<!>length
+    }
+    if (y == null || x != y) {
+        x<!UNSAFE_CALL!>.<!>length
+        y<!UNSAFE_CALL!>.<!>length
+    }
+    else {
+        // Both not null
+        <!DEBUG_INFO_SMARTCAST!>x<!>.length
+        <!DEBUG_INFO_SMARTCAST!>y<!>.length
+    }
+}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.txt b/compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.txt
new file mode 100644
index 00000000000..c752ca6226b
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.txt
@@ -0,0 +1,3 @@
+package
+
+public fun foo(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/smartCasts/complexComparison.kt b/compiler/testData/diagnostics/tests/smartCasts/complexComparison.kt
new file mode 100644
index 00000000000..f9d0d54bc81
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/smartCasts/complexComparison.kt
@@ -0,0 +1,22 @@
+fun foo(x: String?, y: String?, z: String?, w: String?) {
+    if (x != null && y != null && (x == z || y == z))
+        <!DEBUG_INFO_SMARTCAST!>z<!>.length
+    else
+        z<!UNSAFE_CALL!>.<!>length
+    if (x != null || y != null || (x != z && y != z))
+        z<!UNSAFE_CALL!>.<!>length
+    else
+        z<!UNSAFE_CALL!>.<!>length
+    if (x == null || y == null || (x != z && y != z))
+        z<!UNSAFE_CALL!>.<!>length
+    else
+        <!DEBUG_INFO_SMARTCAST!>z<!>.length
+    if (x != null && y == x && z == y && w == z)
+        <!DEBUG_INFO_SMARTCAST!>w<!>.length
+    else
+        w<!UNSAFE_CALL!>.<!>length
+    if ((x != null && y == x) || (z != null && y == z))
+        <!DEBUG_INFO_SMARTCAST!>y<!>.length
+    else
+        y<!UNSAFE_CALL!>.<!>length
+}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/smartCasts/complexComparison.txt b/compiler/testData/diagnostics/tests/smartCasts/complexComparison.txt
new file mode 100644
index 00000000000..b935bc5fd2e
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/smartCasts/complexComparison.txt
@@ -0,0 +1,3 @@
+package
+
+public fun foo(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?, /*2*/ z: kotlin.String?, /*3*/ w: kotlin.String?): kotlin.Unit
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
index 3373ae214f1..e87ff1a0553 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
@@ -14298,6 +14298,18 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("comparisonUnderAnd.kt")
+            public void testComparisonUnderAnd() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("complexComparison.kt")
+            public void testComplexComparison() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/complexComparison.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("dataFlowInfoForArguments.kt")
             public void testDataFlowInfoForArguments() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/dataFlowInfoForArguments.kt");