@Nullable
  public static PyType getType(@NotNull PsiElement resolved, @NotNull List<PyType> elementTypes) {
    final String qualifiedName = getQualifiedName(resolved);

    final List<Integer> paramListTypePositions = new ArrayList<>();
    final List<Integer> ellipsisTypePositions = new ArrayList<>();
    for (int i = 0; i < elementTypes.size(); i++) {
      final PyType type = elementTypes.get(i);
      if (type instanceof PyTypeParser.ParameterListType) {
        paramListTypePositions.add(i);
      } else if (type instanceof PyTypeParser.EllipsisType) {
        ellipsisTypePositions.add(i);
      }
    }

    if (!paramListTypePositions.isEmpty()) {
      if (!("typing.Callable".equals(qualifiedName) && paramListTypePositions.equals(list(0)))) {
        return null;
      }
    }
    if (!ellipsisTypePositions.isEmpty()) {
      if (!("typing.Callable".equals(qualifiedName) && ellipsisTypePositions.equals(list(0))
          || "typing.Tuple".equals(qualifiedName)
              && ellipsisTypePositions.equals(list(1))
              && elementTypes.size() == 2)) {
        return null;
      }
    }

    if ("typing.Union".equals(qualifiedName)) {
      return PyUnionType.union(elementTypes);
    }
    if ("typing.Optional".equals(qualifiedName) && elementTypes.size() == 1) {
      return PyUnionType.union(elementTypes.get(0), PyNoneType.INSTANCE);
    }
    if ("typing.Callable".equals(qualifiedName) && elementTypes.size() == 2) {
      final PyTypeParser.ParameterListType paramList =
          as(elementTypes.get(0), PyTypeParser.ParameterListType.class);
      if (paramList != null) {
        return new PyCallableTypeImpl(paramList.getCallableParameters(), elementTypes.get(1));
      }
      if (elementTypes.get(0) instanceof PyTypeParser.EllipsisType) {
        return new PyCallableTypeImpl(null, elementTypes.get(1));
      }
    }
    if ("typing.Tuple".equals(qualifiedName)) {
      if (elementTypes.size() > 1 && elementTypes.get(1) instanceof PyTypeParser.EllipsisType) {
        return PyTupleType.createHomogeneous(resolved, elementTypes.get(0));
      }
      return PyTupleType.create(resolved, elementTypes);
    }
    final PyType builtinCollection = getBuiltinCollection(resolved);
    if (builtinCollection instanceof PyClassType) {
      final PyClassType classType = (PyClassType) builtinCollection;
      return new PyCollectionTypeImpl(classType.getPyClass(), false, elementTypes);
    }
    return null;
  }
 @Nullable
 private Ref<PyType> getTypeOfProperty(
     @Nullable PyType qualifierType, @NotNull String name, @NotNull TypeEvalContext context) {
   if (qualifierType instanceof PyClassType) {
     final PyClassType classType = (PyClassType) qualifierType;
     PyClass pyClass = classType.getPyClass();
     Property property = pyClass.findProperty(name, true);
     if (property != null) {
       if (classType.isDefinition()) {
         return Ref.<PyType>create(
             PyBuiltinCache.getInstance(pyClass).getObjectType(PyNames.PROPERTY));
       }
       if (AccessDirection.of(this) == AccessDirection.READ) {
         final PyType type = property.getType(context);
         if (type != null) {
           return Ref.create(type);
         }
       }
       return Ref.create();
     }
   } else if (qualifierType instanceof PyUnionType) {
     final PyUnionType unionType = (PyUnionType) qualifierType;
     for (PyType type : unionType.getMembers()) {
       final Ref<PyType> result = getTypeOfProperty(type, name, context);
       if (result != null) {
         return result;
       }
     }
   }
   return null;
 }
  @Nullable
  @Override
  public PyType getReturnType(
      @NotNull TypeEvalContext context, @Nullable PyQualifiedExpression callSite) {
    final PyType type = getGenericReturnType(context, callSite);

    if (callSite == null) {
      return type;
    }
    final PyTypeChecker.AnalyzeCallResults results =
        PyTypeChecker.analyzeCallSite(callSite, context);

    if (PyTypeChecker.hasGenerics(type, context)) {
      if (results != null) {
        final Map<PyGenericType, PyType> substitutions =
            PyTypeChecker.unifyGenericCall(
                this, results.getReceiver(), results.getArguments(), context);
        if (substitutions != null) {
          return PyTypeChecker.substitute(type, substitutions, context);
        }
      }
      return null;
    }
    if (results != null && isDynamicallyEvaluated(results.getArguments().values(), context)) {
      return PyUnionType.createWeakType(type);
    } else {
      return type;
    }
  }
 @Nullable
 private static PyType getType(@NotNull PyExpression expression, @NotNull Context context) {
   final List<PyType> members = Lists.newArrayList();
   for (PsiElement resolved : tryResolving(expression, context.getTypeContext())) {
     members.add(getTypeForResolvedElement(resolved, context));
   }
   return PyUnionType.union(members);
 }
 @Nullable
 private static PyType getGenericTypeBound(
     @NotNull PyExpression[] typeVarArguments, @NotNull Context context) {
   final List<PyType> types = new ArrayList<>();
   for (int i = 1; i < typeVarArguments.length; i++) {
     types.add(getType(typeVarArguments[i], context));
   }
   return PyUnionType.union(types);
 }
  public PyType getType(@NotNull TypeEvalContext context, @NotNull TypeEvalContext.Key key) {
    if (!TypeEvalStack.mayEvaluate(this)) {
      return null;
    }
    try {
      final boolean qualified = isQualified();
      if (!qualified) {
        String name = getReferencedName();
        if (PyNames.NONE.equals(name)) {
          return PyNoneType.INSTANCE;
        }
      }
      PyType type = getTypeFromProviders(context);
      if (type != null) {
        return type;
      }
      if (qualified) {
        PyType maybe_type = PyUtil.getSpecialAttributeType(this, context);
        if (maybe_type != null) return maybe_type;
        Ref<PyType> typeOfProperty = getTypeOfProperty(context);
        if (typeOfProperty != null) {
          return typeOfProperty.get();
        }
      }
      final PsiPolyVariantReference reference =
          getReference(PyResolveContext.noImplicits().withTypeEvalContext(context));
      final List<PsiElement> targets = PyUtil.multiResolveTopPriority(reference);
      if (targets.isEmpty()) {
        return getQualifiedReferenceTypeByControlFlow(context);
      }

      final List<PyType> members = new ArrayList<PyType>();
      for (PsiElement target : targets) {
        if (target == this || target == null) {
          continue;
        }
        if (!target.isValid()) {
          LOG.error(
              "Reference "
                  + this
                  + " resolved to invalid element "
                  + target
                  + " (text="
                  + target.getText()
                  + ")");
          continue;
        }
        members.add(getTypeFromTarget(target, context, this));
      }

      return PyUnionType.union(members);
    } finally {
      TypeEvalStack.evaluated(this);
    }
  }
 @Nullable
 private static PyType getOptionalTypeFromDefaultNone(
     @NotNull PyNamedParameter param, @NotNull PyType type, @NotNull TypeEvalContext context) {
   final PyExpression defaultValue = param.getDefaultValue();
   if (defaultValue != null) {
     final PyType defaultType = context.getType(defaultValue);
     if (defaultType instanceof PyNoneType) {
       return PyUnionType.union(type, defaultType);
     }
   }
   return null;
 }
 @Nullable
 private static PyType getUnionType(@NotNull PsiElement element, @NotNull Context context) {
   if (element instanceof PySubscriptionExpression) {
     final PySubscriptionExpression subscriptionExpr = (PySubscriptionExpression) element;
     final PyExpression operand = subscriptionExpr.getOperand();
     final Collection<String> operandNames =
         resolveToQualifiedNames(operand, context.getTypeContext());
     if (operandNames.contains("typing.Union")) {
       return PyUnionType.union(getIndexTypes(subscriptionExpr, context));
     }
   }
   return null;
 }
 @Override
 public void visitPyReturnStatement(PyReturnStatement node) {
   if (PsiTreeUtil.getParentOfType(node, ScopeOwner.class, true) == myFunction) {
     final PyExpression expr = node.getExpression();
     PyType returnType;
     returnType = expr == null ? PyNoneType.INSTANCE : myContext.getType(expr);
     if (!myHasReturns) {
       myResult = returnType;
       myHasReturns = true;
     } else {
       myResult = PyUnionType.union(myResult, returnType);
     }
   }
 }
 @Override
 public PyType getType(@NotNull TypeEvalContext context, @NotNull TypeEvalContext.Key key) {
   for (PyTypeProvider provider : Extensions.getExtensions(PyTypeProvider.EP_NAME)) {
     final PyType type = provider.getCallableType(this, context);
     if (type != null) {
       return type;
     }
   }
   final PyFunctionTypeImpl type = new PyFunctionTypeImpl(this);
   if (PyKnownDecoratorUtil.hasUnknownDecorator(this, context) && getProperty() == null) {
     return PyUnionType.createWeakType(type);
   }
   return type;
 }
 @Override
 public PyType getType(@NotNull TypeEvalContext context, @NotNull TypeEvalContext.Key key) {
   for (PyTypeProvider provider : Extensions.getExtensions(PyTypeProvider.EP_NAME)) {
     final PyType type = provider.getCallableType(this, context);
     if (type != null) {
       return type;
     }
   }
   final PyFunctionType type = new PyFunctionType(this);
   if (getDecoratorList() != null) {
     return PyUnionType.createWeakType(type);
   }
   return type;
 }
  @Nullable
  private Ref<? extends PyType> getYieldStatementType(@NotNull final TypeEvalContext context) {
    Ref<PyType> elementType = null;
    final PyBuiltinCache cache = PyBuiltinCache.getInstance(this);
    final PyStatementList statements = getStatementList();
    final Set<PyType> types = new LinkedHashSet<>();
    statements.accept(
        new PyRecursiveElementVisitor() {
          @Override
          public void visitPyYieldExpression(PyYieldExpression node) {
            final PyExpression expr = node.getExpression();
            final PyType type = expr != null ? context.getType(expr) : null;
            if (node.isDelegating() && type instanceof PyCollectionType) {
              final PyCollectionType collectionType = (PyCollectionType) type;
              // TODO: Select the parameter types that matches T in Iterable[T]
              final List<PyType> elementTypes = collectionType.getElementTypes(context);
              types.add(elementTypes.isEmpty() ? null : elementTypes.get(0));
            } else {
              types.add(type);
            }
          }

          @Override
          public void visitPyFunction(PyFunction node) {
            // Ignore nested functions
          }
        });
    final int n = types.size();
    if (n == 1) {
      elementType = Ref.create(types.iterator().next());
    } else if (n > 0) {
      elementType = Ref.create(PyUnionType.union(types));
    }
    if (elementType != null) {
      final PyClass generator = cache.getClass(PyNames.FAKE_GENERATOR);
      if (generator != null) {
        final List<PyType> parameters =
            Arrays.asList(elementType.get(), null, getReturnStatementType(context));
        return Ref.create(new PyCollectionTypeImpl(generator, false, parameters));
      }
    }
    if (!types.isEmpty()) {
      return Ref.create(null);
    }
    return null;
  }
 @Override
 public PyType getType(@NotNull TypeEvalContext context, @NotNull TypeEvalContext.Key key) {
   for (PyTypeProvider provider : Extensions.getExtensions(PyTypeProvider.EP_NAME)) {
     final PyType type = provider.getCallableType(this, context);
     if (type != null) {
       return type;
     }
   }
   final boolean hasCustomDecorators =
       PyUtil.hasCustomDecorators(this)
           && !PyUtil.isDecoratedAsAbstract(this)
           && getProperty() == null;
   final PyFunctionType type = new PyFunctionType(this);
   if (hasCustomDecorators) {
     return PyUnionType.createWeakType(type);
   }
   return type;
 }
  @Nullable
  private Ref<? extends PyType> getYieldStatementType(@NotNull final TypeEvalContext context) {
    Ref<PyType> elementType = null;
    final PyBuiltinCache cache = PyBuiltinCache.getInstance(this);
    final PyStatementList statements = getStatementList();
    final Set<PyType> types = new LinkedHashSet<PyType>();
    if (statements != null) {
      statements.accept(
          new PyRecursiveElementVisitor() {
            @Override
            public void visitPyYieldExpression(PyYieldExpression node) {
              final PyType type = context.getType(node);
              if (node.isDelegating() && type instanceof PyCollectionType) {
                final PyCollectionType collectionType = (PyCollectionType) type;
                types.add(collectionType.getElementType(context));
              } else {
                types.add(type);
              }
            }

            @Override
            public void visitPyFunction(PyFunction node) {
              // Ignore nested functions
            }
          });
      final int n = types.size();
      if (n == 1) {
        elementType = Ref.create(types.iterator().next());
      } else if (n > 0) {
        elementType = Ref.create(PyUnionType.union(types));
      }
    }
    if (elementType != null) {
      final PyClass generator = cache.getClass(PyNames.FAKE_GENERATOR);
      if (generator != null) {
        return Ref.create(new PyCollectionTypeImpl(generator, false, elementType.get()));
      }
    }
    if (!types.isEmpty()) {
      return Ref.create(null);
    }
    return null;
  }
 @Nullable
 private static Ref<PyType> getOptionalType(
     @NotNull PsiElement element, @NotNull Context context) {
   if (element instanceof PySubscriptionExpression) {
     final PySubscriptionExpression subscriptionExpr = (PySubscriptionExpression) element;
     final PyExpression operand = subscriptionExpr.getOperand();
     final Collection<String> operandNames =
         resolveToQualifiedNames(operand, context.getTypeContext());
     if (operandNames.contains("typing.Optional")) {
       final PyExpression indexExpr = subscriptionExpr.getIndexExpression();
       if (indexExpr != null) {
         final PyType type = getType(indexExpr, context);
         if (type != null) {
           return Ref.create(PyUnionType.union(type, PyNoneType.INSTANCE));
         }
       }
       return Ref.create();
     }
   }
   return null;
 }
 private static PyType getTypeByControlFlow(
     @NotNull String name,
     @NotNull TypeEvalContext context,
     @NotNull PyExpression anchor,
     @NotNull ScopeOwner scopeOwner) {
   PyAugAssignmentStatement augAssignment =
       PsiTreeUtil.getParentOfType(anchor, PyAugAssignmentStatement.class);
   try {
     final PyElement element = augAssignment != null ? augAssignment : anchor;
     final List<ReadWriteInstruction> defs =
         PyDefUseUtil.getLatestDefs(scopeOwner, name, element, true);
     if (!defs.isEmpty()) {
       PyType type = defs.get(0).getType(context, anchor);
       for (int i = 1; i < defs.size(); i++) {
         type = PyUnionType.union(type, defs.get(i).getType(context, anchor));
       }
       return type;
     }
   } catch (PyDefUseUtil.InstructionNotFoundException ignored) {
   }
   return null;
 }
 public PyType getType(@NotNull TypeEvalContext context, @NotNull TypeEvalContext.Key key) {
   if (isOperator("and") || isOperator("or")) {
     final PyExpression left = getLeftExpression();
     final PyType leftType = left != null ? context.getType(left) : null;
     final PyExpression right = getRightExpression();
     final PyType rightType = right != null ? context.getType(right) : null;
     if (leftType == null && rightType == null) {
       return null;
     }
     return PyUnionType.union(leftType, rightType);
   }
   final PyTypeChecker.AnalyzeCallResults results = PyTypeChecker.analyzeCall(this, context);
   if (results != null) {
     final PyType type = results.getCallable().getCallType(context, this);
     if (!PyTypeChecker.isUnknown(type) && !(type instanceof PyNoneType)) {
       return type;
     }
   }
   if (PyNames.COMPARISON_OPERATORS.contains(getReferencedName())) {
     return PyBuiltinCache.getInstance(this).getBoolType();
   }
   return null;
 }
 @Nullable
 private PyType analyzeCallType(
     @Nullable PyType type,
     @Nullable PyExpression receiver,
     @NotNull Map<PyExpression, PyNamedParameter> parameters,
     @NotNull TypeEvalContext context) {
   if (PyTypeChecker.hasGenerics(type, context)) {
     final Map<PyGenericType, PyType> substitutions =
         PyTypeChecker.unifyGenericCall(receiver, parameters, context);
     if (substitutions != null) {
       type = PyTypeChecker.substitute(type, substitutions, context);
     } else {
       type = null;
     }
   }
   if (receiver != null) {
     type = replaceSelf(type, receiver, context);
   }
   if (type != null && isDynamicallyEvaluated(parameters.values(), context)) {
     type = PyUnionType.createWeakType(type);
   }
   return type;
 }