a test for how dfa treats static final string comparison (IDEA-169892)

java/java-tests/testData/inspection/dataFlow/fixture/InternedStringConstants.java

@@ -0,0 +1,10 @@
+class Example {
+
+  public static final String FIRST = "f";
+  public static final String SECOND = "d";
+  public static final String THIRD = FIRST + SECOND;
+
+  public static void main(String[] args) {
+    System.out.println(THIRD == "fd");
+  }
+}

java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java

@@ -95,6 +95,7 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testCheckEnumConstantConstructor() { doTest(); }
   public void testCompareToEnumConstant() throws Throwable { doTest(); }
   public void testEqualsConstant() throws Throwable { doTest(); }
+  public void testInternedStringConstants() throws Throwable { doTest(); }
   public void testDontSaveTypeValue() { doTest(); }
   public void testFinalLoopVariableInstanceof() throws Throwable { doTest(); }
   public void testGreaterIsNotEquals() throws Throwable { doTest(); }