dfa: don't suggest to simplify boolean expressions with side effects (IDEA-145401)

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DataFlowInspectionBase.java

@@ -737,6 +737,8 @@ public class DataFlowInspectionBase extends BaseJavaBatchLocalInspectionTool {
 
   private static SimplifyBooleanExpressionFix createIntention(PsiElement element, boolean value) {
     if (!(element instanceof PsiExpression)) return null;
+    if (PsiTreeUtil.findChildOfType(element, PsiAssignmentExpression.class) != null) return null;
+
     final PsiExpression expression = (PsiExpression)element;
     while (element.getParent() instanceof PsiExpression) {
       element = element.getParent();

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

@@ -0,0 +1,9 @@
+class Contracts {
+
+  boolean x;
+
+  public boolean testSideEffect() {
+    return x && <warning descr="Condition '!(x = false)' is always 'true' when reached">!(x =<caret> false)</warning>;
+  }
+
+}

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

@@ -371,6 +371,11 @@ public class DataFlowInspectionTest extends LightCodeInsightFixtureTestCase {
     myFixture.checkResultByFile(getTestName(false) + "_after.java");
   }
 
+  public void testDontSimplifyAssignment() {
+    doTest();
+    assertEmpty(myFixture.filterAvailableIntentions("Simplify"));
+  }
+
   public void testAssertThat() {
     myFixture.addClass("package org.hamcrest; public class CoreMatchers { " +
                        "public static <T> Matcher<T> notNullValue() {}\n" +