From 09d57e4993fb7e82dc2685ace77376e24e25dc9d Mon Sep 17 00:00:00 2001
From: Anna Kozlova <anna.kozlova@jetbrains.com>
Date: Wed, 29 Apr 2020 08:18:44 +0200
Subject: [PATCH] compound assignment: allow assignment to string super types
 (IDEA-238812)

GitOrigin-RevId: 56d7dd94bc8e1b728aef2c59a54bee76ad43df74
---
 .../src/com/intellij/psi/util/TypeConversionUtil.java       | 6 ++++--
 .../advHighlighting6/AssignmentFromStringToObject.java      | 4 ++++
 2 files changed, 8 insertions(+), 2 deletions(-)

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