diff --git a/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java b/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java
index e285b7f3e074..e95a44272924 100644
--- a/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java
+++ b/java/java-psi-api/src/com/intellij/psi/util/TypeConversionUtil.java
@@ -551,8 +551,10 @@ public class TypeConversionUtil {
         resultTypeRank = STRING_RANK;
       }
       else if (rtype.equalsToText(JAVA_LANG_STRING)) {
-        isApplicable = !isVoidType(ltype);
-        resultTypeRank = STRING_RANK;
+        if (isVoidType(ltype)) {
+          return false;
+        }
+        return !strict || ltype.isAssignableFrom(rtype);
       }
       else if (isPrimitiveAndNotNullOrWrapper(ltype) && isPrimitiveAndNotNullOrWrapper(rtype)) {
         resultTypeRank = Math.max(ltypeRank, rtypeRank);
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting6/AssignmentFromStringToObject.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting6/AssignmentFromStringToObject.java
index d9daa319dbcd..603716bc6bce 100644
--- a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting6/AssignmentFromStringToObject.java
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting6/AssignmentFromStringToObject.java
@@ -3,5 +3,9 @@ class Test {
     Object o = "";
     <warning descr="Operator '+' cannot be applied to 'java.lang.Object', 'java.lang.String'">o += ""</warning>;
     System.out.println(o);
+
+    CharSequence c = "";
+    c += "";
+    System.out.println(c);
   }
 }
\ No newline at end of file