DFA: support value escaping on custom objects (IDEA-188303)

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

@@ -582,6 +582,9 @@ public class StandardInstructionVisitor extends InstructionVisitor {
         }
       }
       DfaValue value = factory.createTypeValue(type, nullability);
+      if (!instruction.shouldFlushFields() && instruction.getContext() instanceof PsiNewExpression) {
+        value = factory.withFact(value, DfaFactType.LOCALITY, true);
+      }
       return factory.withFact(value, DfaFactType.MUTABILITY, mutable);
     }
     LongRangeSet range = LongRangeSet.fromType(type);

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/instructions/MethodCallInstruction.java

@@ -24,9 +24,7 @@ import com.siyeh.ig.callMatcher.CallMatcher;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 
 
 public class MethodCallInstruction extends Instruction {
@@ -198,8 +196,24 @@ public class MethodCallInstruction extends Instruction {
   }
 
   private boolean isPureCall() {
-    if (myTargetMethod == null) return false;
-    return ControlFlowAnalyzer.isPure(myTargetMethod) || SpecialField.findSpecialField(myTargetMethod) != null;
+    if (myTargetMethod != null) {
+      return ControlFlowAnalyzer.isPure(myTargetMethod) || SpecialField.findSpecialField(myTargetMethod) != null;
+    }
+    if (!(myContext instanceof PsiNewExpression)) return false;
+    PsiNewExpression newExpression = (PsiNewExpression)myContext;
+    if (newExpression.getArgumentList() == null || !newExpression.getArgumentList().isEmpty()) return false;
+    PsiJavaCodeReferenceElement classReference = newExpression.getClassReference();
+    if (classReference == null) return false;
+    PsiClass clazz = ObjectUtils.tryCast(classReference.resolve(), PsiClass.class);
+    if (clazz == null) return false;
+    Set<PsiClass> visited = new HashSet<>();
+    while (true) {
+      for (PsiMethod ctor : clazz.getConstructors()) {
+        if(ctor.getParameterList().isEmpty()) return ControlFlowAnalyzer.isPure(ctor);
+      }
+      clazz = clazz.getSuperClass();
+      if (clazz == null || !visited.add(clazz)) return false;
+    }
   }
 
   @Nullable

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

@@ -0,0 +1,18 @@
+import java.util.*;
+
+import org.jetbrains.annotations.*;
+
+class ObjectLocality {
+  int x;
+
+  void test() {
+    ObjectLocality o = new ObjectLocality();
+    o.x = 5;
+    unknown();
+    <warning descr="Variable is already assigned to this value">o.x</warning> = 5;
+    o.unknown();
+    o.x = 5;
+  }
+
+  native void unknown();
+}

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

@@ -609,4 +609,5 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   }
   public void testMergedInitializerAndConstructor() { doTest(); }
   public void testClassMethodsInlining() { doTest(); }
+  public void testObjectLocality() { doTest(); }
 }