OptionalRefactoringUtil: do not suggest opt.map().stream() -> opt.stream().flatMap() if operation may have side-effect

Side-effect is allowed for Optional.map, but not allowed for Stream.flatMap, and actually may cause a semantics change
Fixes IDEA-207178 Incorrect simplification of optional suggested by inspection

java/java-impl/src/com/intellij/codeInspection/util/OptionalRefactoringUtil.java

@@ -9,10 +9,7 @@ import com.intellij.psi.util.PsiUtil;
 import com.intellij.psi.util.TypeConversionUtil;
 import com.intellij.refactoring.util.RefactoringUtil;
 import com.intellij.util.ObjectUtils;
-import com.siyeh.ig.psiutils.BoolUtils;
-import com.siyeh.ig.psiutils.ExpressionUtils;
-import com.siyeh.ig.psiutils.JavaPsiMathUtil;
-import com.siyeh.ig.psiutils.StreamApiUtil;
+import com.siyeh.ig.psiutils.*;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -122,7 +119,7 @@ public class OptionalRefactoringUtil {
             }
           }
           String flatMapOperationName = StreamRefactoringUtil.getFlatMapOperationName(var.getType(), elementType);
-          if(flatMapOperationName != null) {
+          if(flatMapOperationName != null && !SideEffectChecker.mayHaveSideEffects(trueExpression)) {
             return qualifier + ".stream()."+flatMapOperationName+"(" + LambdaUtil.createLambda(var, trueExpression) + ")";
           }
         }

java/java-tests/testData/inspection/optionalChains/afterStreamJava9.java

@@ -15,7 +15,19 @@ public final class MyClass {
     p.name().stream().mapToInt(String::length).forEach(System.out::println);
     p.name().stream().flatMapToInt(String::chars).forEach(System.out::println);
     p.name().filter(n -> !n.isEmpty()).stream().forEach(System.out::println);
+    
+    p.name().stream().flatMap(MyClass::createStream);
+    p.name().map(m -> createStreamSideEffect(m)).orElse(Stream.empty());
 
     Stream<Integer> stream = opt.stream();
   }
+  
+  static Stream<String> createStream(String s) {
+    return Stream.of(s, s);
+  }
+  
+  static Stream<String> createStreamSideEffect(String s) {
+    System.out.println(s);
+    return Stream.of(s, s);
+  }
 }

java/java-tests/testData/inspection/optionalChains/beforeStreamJava9.java

@@ -15,7 +15,19 @@ public final class MyClass {
     p.name().map(n -> IntStream.of(n.length())).orElseGet(IntStream::empty).forEach(System.out::println);
     p.name().map(String::chars).orElseGet(IntStream::empty).forEach(System.out::println);
     p.name().map(n -> n.isEmpty() ? Stream.empty() : Stream.of(n)).orElseGet(Stream::empty).forEach(System.out::println);
+    
+    p.name().map(m -> createStream(m)).orElse(Stream.empty());
+    p.name().map(m -> createStreamSideEffect(m)).orElse(Stream.empty());
 
     Stream<Integer> stream = opt.map(Stream::of).orElseGet(Stream::empty);
   }
+  
+  static Stream<String> createStream(String s) {
+    return Stream.of(s, s);
+  }
+  
+  static Stream<String> createStreamSideEffect(String s) {
+    System.out.println(s);
+    return Stream.of(s, s);
+  }
 }

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

@@ -20,12 +20,13 @@ import com.intellij.codeInspection.LocalInspectionTool;
 import com.intellij.codeInspection.SimplifyOptionalCallChainsInspection;
 import com.intellij.openapi.projectRoots.Sdk;
 import com.intellij.testFramework.IdeaTestUtil;
+import com.intellij.testFramework.PsiTestUtil;
 import org.jetbrains.annotations.NotNull;
 
 public class SimplifyOptionalCallChainsInspectionTest extends LightQuickFixParameterizedTestCase {
   @Override
   protected Sdk getProjectJDK() {
-    return IdeaTestUtil.getMockJdk9();
+    return PsiTestUtil.addJdkAnnotations(IdeaTestUtil.getMockJdk9());
   }
 
   @NotNull