@Nullable
 private static PsiType getInferredTypes(
     GrReferenceExpressionImpl refExpr, @Nullable PsiElement resolved) {
   final GrExpression qualifier = refExpr.getQualifier();
   if (qualifier == null && !(resolved instanceof PsiClass)) {
     return TypeInferenceHelper.getCurrentContext().getVariableType(refExpr);
   } else if (qualifier != null) {
     // map access
     PsiType qType = qualifier.getType();
     if (qType instanceof PsiClassType && !(qType instanceof GrMapType)) {
       PsiClassType.ClassResolveResult qResult = ((PsiClassType) qType).resolveGenerics();
       PsiClass clazz = qResult.getElement();
       if (clazz != null) {
         PsiClass mapClass =
             JavaPsiFacade.getInstance(refExpr.getProject())
                 .findClass(CommonClassNames.JAVA_UTIL_MAP, refExpr.getResolveScope());
         if (mapClass != null && mapClass.getTypeParameters().length == 2) {
           PsiSubstitutor substitutor =
               TypeConversionUtil.getClassSubstitutor(mapClass, clazz, qResult.getSubstitutor());
           if (substitutor != null) {
             return TypeConversionUtil.erasure(
                 substitutor.substitute(mapClass.getTypeParameters()[1]));
           }
         }
       }
     }
   }
   return null;
 }
 @Nullable
 private static PsiType getTypeFromMapAccess(@NotNull GrReferenceExpressionImpl ref) {
   // map access
   GrExpression qualifier = ref.getQualifierExpression();
   if (qualifier != null) {
     PsiType qType = qualifier.getNominalType();
     if (qType instanceof PsiClassType) {
       PsiClassType.ClassResolveResult qResult = ((PsiClassType) qType).resolveGenerics();
       PsiClass clazz = qResult.getElement();
       if (clazz != null) {
         PsiClass mapClass =
             JavaPsiFacade.getInstance(ref.getProject())
                 .findClass(CommonClassNames.JAVA_UTIL_MAP, ref.getResolveScope());
         if (mapClass != null && mapClass.getTypeParameters().length == 2) {
           PsiSubstitutor substitutor =
               TypeConversionUtil.getClassSubstitutor(mapClass, clazz, qResult.getSubstitutor());
           if (substitutor != null) {
             return TypeConversionUtil.erasure(
                 substitutor.substitute(mapClass.getTypeParameters()[1]));
           }
         }
       }
     }
   }
   return null;
 }
  private GroovyResolveResult[] resolveTypeOrProperty() {
    if (isDefinitelyKeyOfMap()) return GroovyResolveResult.EMPTY_ARRAY;

    final GroovyResolveResult[] results = resolveTypeOrPropertyInner();
    if (results.length == 0) return GroovyResolveResult.EMPTY_ARRAY;

    if (!ResolveUtil.mayBeKeyOfMap(this)) return results;

    // filter out all members from super classes. We should return only accessible members from map
    // classes
    List<GroovyResolveResult> filtered = new ArrayList<GroovyResolveResult>();
    for (GroovyResolveResult result : results) {
      final PsiElement element = result.getElement();
      if (element instanceof PsiMember) {
        if (((PsiMember) element).hasModifierProperty(PsiModifier.PRIVATE)) continue;
        final PsiClass containingClass = ((PsiMember) element).getContainingClass();
        if (containingClass != null) {
          if (!InheritanceUtil.isInheritor(containingClass, CommonClassNames.JAVA_UTIL_MAP))
            continue;
          final String name = containingClass.getQualifiedName();
          if (name != null && name.startsWith("java.")) continue;
          if (containingClass.getLanguage() != GroovyFileType.GROOVY_LANGUAGE
              && !InheritanceUtil.isInheritor(
                  containingClass, GroovyCommonClassNames.DEFAULT_BASE_CLASS_NAME)) {
            continue;
          }
        }
      }
      filtered.add(result);
    }

    return ContainerUtil.toArray(filtered, new GroovyResolveResult[filtered.size()]);
  }
  public GrReferenceExpression bindToElementViaStaticImport(@NotNull PsiMember member) {
    if (getQualifier() != null) {
      throw new IncorrectOperationException("Reference has qualifier");
    }

    if (StringUtil.isEmpty(getReferenceName())) {
      throw new IncorrectOperationException("Reference has empty name");
    }

    PsiClass containingClass = member.getContainingClass();
    if (containingClass == null) {
      throw new IncorrectOperationException("Member has no containing class");
    }
    final PsiFile file = getContainingFile();
    if (file instanceof GroovyFile) {
      GroovyPsiElementFactory factory = GroovyPsiElementFactory.getInstance(getProject());
      String text = "import static " + containingClass.getQualifiedName() + "." + member.getName();
      final GrImportStatement statement = factory.createImportStatementFromText(text);
      ((GroovyFile) file).addImport(statement);
    }
    return this;
  }
  @Nullable
  private PsiType getNominalTypeInner(PsiElement resolved) {
    if (resolved == null && !"class".equals(getReferenceName())) {
      resolved = resolve();
    }

    if (resolved instanceof PsiClass) {
      final PsiElementFactory factory = JavaPsiFacade.getInstance(getProject()).getElementFactory();
      if (PsiUtil.isInstanceThisRef(this)) {
        final PsiClassType categoryType = GdkMethodUtil.getCategoryType((PsiClass) resolved);
        if (categoryType != null) {
          return categoryType;
        } else {
          return factory.createType((PsiClass) resolved);
        }
      }
      if (getParent() instanceof GrReferenceExpression || PsiUtil.isSuperReference(this)) {
        return factory.createType((PsiClass) resolved);
      } else {
        return TypesUtil.createJavaLangClassType(
            factory.createType((PsiClass) resolved), getProject(), getResolveScope());
      }
    }

    if (resolved instanceof GrVariable) {
      return ((GrVariable) resolved).getDeclaredType();
    }

    if (resolved instanceof PsiVariable) {
      return ((PsiVariable) resolved).getType();
    }

    if (resolved instanceof PsiMethod) {
      PsiMethod method = (PsiMethod) resolved;
      if (PropertyUtil.isSimplePropertySetter(method)
          && !method.getName().equals(getReferenceName())) {
        return method.getParameterList().getParameters()[0].getType();
      }

      // 'class' property with explicit generic
      PsiClass containingClass = method.getContainingClass();
      if (containingClass != null
          && CommonClassNames.JAVA_LANG_OBJECT.equals(containingClass.getQualifiedName())
          && "getClass".equals(method.getName())) {
        return TypesUtil.createJavaLangClassType(
            GrReferenceResolveUtil.getQualifierType(this), getProject(), getResolveScope());
      }

      return PsiUtil.getSmartReturnType(method);
    }

    if (resolved instanceof GrReferenceExpression) {
      PsiElement parent = resolved.getParent();
      if (parent instanceof GrAssignmentExpression) {
        GrAssignmentExpression assignment = (GrAssignmentExpression) parent;
        if (resolved.equals(assignment.getLValue())) {
          GrExpression rValue = assignment.getRValue();
          if (rValue != null) {
            PsiType rType = rValue.getType();
            if (rType != null) {
              return rType;
            }
          }
        }
      }
    }

    if (resolved == null) {
      final PsiType fromClassRef = getTypeFromClassRef(this);
      if (fromClassRef != null) {
        return fromClassRef;
      }

      final PsiType fromMapAccess = getTypeFromMapAccess(this);
      if (fromMapAccess != null) {
        return fromMapAccess;
      }

      final PsiType fromSpreadOperator = getTypeFromSpreadOperator(this);
      if (fromSpreadOperator != null) {
        return fromSpreadOperator;
      }
    }

    return null;
  }
  @Nullable
  private PsiType getNominalTypeInner(@Nullable PsiElement resolved) {
    if (resolved == null && !"class".equals(getReferenceName())) {
      resolved = resolve();
    }

    if (resolved instanceof PsiClass) {
      final PsiElementFactory factory = JavaPsiFacade.getInstance(getProject()).getElementFactory();
      if (PsiUtil.isInstanceThisRef(this)) {
        final PsiClassType categoryType = GdkMethodUtil.getCategoryType((PsiClass) resolved);
        if (categoryType != null) {
          return categoryType;
        } else {
          return factory.createType((PsiClass) resolved);
        }
      } else if (PsiUtil.isSuperReference(this)) {
        PsiClass contextClass = PsiUtil.getContextClass(this);
        if (GrTraitUtil.isTrait(contextClass)) {
          PsiClassType[] extendsTypes = contextClass.getExtendsListTypes();
          PsiClassType[] implementsTypes = contextClass.getImplementsListTypes();

          PsiClassType[] superTypes =
              ArrayUtil.mergeArrays(implementsTypes, extendsTypes, PsiClassType.ARRAY_FACTORY);

          return PsiIntersectionType.createIntersection(ArrayUtil.reverseArray(superTypes));
        }
        return factory.createType((PsiClass) resolved);
      }
      if (getParent() instanceof GrReferenceExpression) {
        return factory.createType((PsiClass) resolved);
      } else {
        return TypesUtil.createJavaLangClassType(
            factory.createType((PsiClass) resolved), getProject(), getResolveScope());
      }
    }

    if (resolved instanceof GrVariable) {
      return ((GrVariable) resolved).getDeclaredType();
    }

    if (resolved instanceof PsiVariable) {
      return ((PsiVariable) resolved).getType();
    }

    if (resolved instanceof PsiMethod) {
      PsiMethod method = (PsiMethod) resolved;
      if (PropertyUtil.isSimplePropertySetter(method)
          && !method.getName().equals(getReferenceName())) {
        return method.getParameterList().getParameters()[0].getType();
      }

      // 'class' property with explicit generic
      PsiClass containingClass = method.getContainingClass();
      if (containingClass != null
          && CommonClassNames.JAVA_LANG_OBJECT.equals(containingClass.getQualifiedName())
          && "getClass".equals(method.getName())) {
        return TypesUtil.createJavaLangClassType(
            PsiImplUtil.getQualifierType(this), getProject(), getResolveScope());
      }

      return PsiUtil.getSmartReturnType(method);
    }

    if (resolved == null) {
      final PsiType fromClassRef = getTypeFromClassRef(this);
      if (fromClassRef != null) {
        return fromClassRef;
      }

      final PsiType fromMapAccess = getTypeFromMapAccess(this);
      if (fromMapAccess != null) {
        return fromMapAccess;
      }

      final PsiType fromSpreadOperator = getTypeFromSpreadOperator(this);
      if (fromSpreadOperator != null) {
        return fromSpreadOperator;
      }
    }

    return null;
  }