diff --git a/java/codeserver/core/src/com/intellij/java/codeserver/core/JavaPsiModuleUtil.java b/java/codeserver/core/src/com/intellij/java/codeserver/core/JavaPsiModuleUtil.java
index b1852a3ce926..cb055cea3325 100644
--- a/java/codeserver/core/src/com/intellij/java/codeserver/core/JavaPsiModuleUtil.java
+++ b/java/codeserver/core/src/com/intellij/java/codeserver/core/JavaPsiModuleUtil.java
@@ -3,6 +3,7 @@ package com.intellij.java.codeserver.core;
 
 import com.intellij.ide.highlighter.ArchiveFileType;
 import com.intellij.openapi.module.Module;
+import com.intellij.openapi.module.ModuleManager;
 import com.intellij.openapi.project.DumbService;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.roots.ModuleRootManager;
@@ -22,14 +23,17 @@ import com.intellij.psi.search.searches.JavaModuleSearch;
 import com.intellij.psi.util.CachedValueProvider;
 import com.intellij.psi.util.CachedValuesManager;
 import com.intellij.psi.util.JavaMultiReleaseUtil;
+import com.intellij.psi.util.PsiUtilCore;
 import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.MultiMap;
+import com.intellij.util.graph.DFSTBuilder;
 import com.intellij.util.graph.Graph;
 import com.intellij.util.graph.GraphGenerator;
 import com.intellij.util.indexing.DumbModeAccessType;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.Unmodifiable;
 import org.jetbrains.jps.model.java.JavaResourceRootType;
 import org.jetbrains.jps.model.java.JavaSourceRootType;
 
@@ -38,6 +42,7 @@ import java.util.function.BiFunction;
 import java.util.jar.JarFile;
 
 import static com.intellij.psi.PsiJavaModule.JAVA_BASE;
+import static java.util.Objects.requireNonNullElse;
 
 /**
  * Utilities related to JPMS modules
@@ -243,6 +248,80 @@ public final class JavaPsiModuleUtil {
     return getRequiresGraph(source).getAllDependencies(source, true);
   }
 
+  /**
+   * @param module module to check for dependency cycles
+   * @return collection of modules that form a dependency cycle
+   */
+  public static @NotNull Collection<PsiJavaModule> findCycle(@NotNull PsiJavaModule module) {
+    Project project = module.getProject();
+    List<Set<PsiJavaModule>> cycles = CachedValuesManager.getManager(project).getCachedValue(project, () ->
+      CachedValueProvider.Result.create(findCycles(project),
+                                        PsiJavaModuleModificationTracker.getInstance(project),
+                                        ProjectRootModificationTracker.getInstance(project)));
+    return requireNonNullElse(ContainerUtil.find(cycles, set -> set.contains(module)), Collections.emptyList());
+  }
+
+  private static @Nullable VirtualFile getVirtualFile(@NotNull PsiJavaModule module) {
+    if (module instanceof LightJavaModule light) {
+      return light.getRootVirtualFile();
+    }
+    return PsiUtilCore.getVirtualFile(module);
+  }
+
+  /*
+   * Looks for cycles between Java modules in the project sources.
+   * Library/JDK modules are excluded in an assumption there can't be any lib -> src dependencies.
+   * Module references are resolved "globally" (i.e., without taking project dependencies into account).
+   */
+  private static @Unmodifiable @NotNull List<Set<PsiJavaModule>> findCycles(@NotNull Project project) {
+    Set<PsiJavaModule> projectModules = new HashSet<>();
+    for (Module module : ModuleManager.getInstance(project).getModules()) {
+      ModuleRootManager moduleRootManager = ModuleRootManager.getInstance(module);
+      List<PsiJavaModule> descriptors = ContainerUtil.mapNotNull(moduleRootManager.getSourceRoots(true),
+                                                                 root -> findDescriptorByFile(root, project));
+      if (descriptors.size() > 2) return Collections.emptyList();  // aborts the process when there are incorrect modules in the project
+
+      if (descriptors.size() == 2) {
+        if (descriptors.stream()
+              .map(d -> getVirtualFile(d))
+              .filter(Objects::nonNull).count() < 2) {
+          return Collections.emptyList();
+        }
+        projectModules.addAll(descriptors);
+      }
+      if (descriptors.size() == 1) projectModules.add(descriptors.get(0));
+    }
+
+    if (!projectModules.isEmpty()) {
+      MultiMap<PsiJavaModule, PsiJavaModule> relations = MultiMap.create();
+      for (PsiJavaModule module : projectModules) {
+        for (PsiRequiresStatement statement : module.getRequires()) {
+          PsiJavaModuleReference ref = statement.getModuleReference();
+          if (ref != null) {
+            ResolveResult[] results = ref.multiResolve(true);
+            if (results.length == 1) {
+              PsiJavaModule dependency = (PsiJavaModule)results[0].getElement();
+              if (dependency != null && projectModules.contains(dependency)) {
+                relations.putValue(module, dependency);
+              }
+            }
+          }
+        }
+      }
+
+      if (!relations.isEmpty()) {
+        Graph<PsiJavaModule> graph = new ChameleonGraph<>(relations, false);
+        DFSTBuilder<PsiJavaModule> builder = new DFSTBuilder<>(graph);
+        Collection<Collection<PsiJavaModule>> components = builder.getComponents();
+        if (!components.isEmpty()) {
+          return ContainerUtil.map(components, elements -> new LinkedHashSet<>(elements));
+        }
+      }
+    }
+
+    return Collections.emptyList();
+  }
+
   /**
    * Represents a dependency conflict when a single package is imported from two modules
    * @param packageName package name
diff --git a/java/codeserver/highlighting/resources/messages/JavaCompilationErrorBundle.properties b/java/codeserver/highlighting/resources/messages/JavaCompilationErrorBundle.properties
index 6fde0e6d9c2d..a0a4be830277 100644
--- a/java/codeserver/highlighting/resources/messages/JavaCompilationErrorBundle.properties
+++ b/java/codeserver/highlighting/resources/messages/JavaCompilationErrorBundle.properties
@@ -492,3 +492,9 @@ module.duplicate.uses=Duplicate ''uses'': {0}
 module.duplicate.provides=Duplicate ''provides'': {0}
 module.file.wrong.location=Module declaration should be located in a module's source root
 module.opens.in.weak.module='opens' is not allowed in an open module
+module.service.enum=The service definition is an enum: {0}
+module.not.found=Module not found: {0}
+module.not.on.path=Module is not in dependencies: {0}
+module.cyclic.dependence=Cyclic dependence: {0}
+module.duplicate.exports.target=Duplicate ''exports'' target: {0}
+module.duplicate.opens.target=Duplicate ''opens'' target: {0}
diff --git a/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/JavaErrorVisitor.java b/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/JavaErrorVisitor.java
index a50e89baf87b..cc24c1255755 100644
--- a/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/JavaErrorVisitor.java
+++ b/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/JavaErrorVisitor.java
@@ -642,6 +642,7 @@ final class JavaErrorVisitor extends JavaElementVisitor {
     super.visitRequiresStatement(statement);
     if (JavaFeature.MODULES.isSufficient(myLanguageLevel)) {
       if (!hasErrorResults() && myLanguageLevel.isAtLeast(LanguageLevel.JDK_10)) myModuleChecker.checkModifiers(statement);
+      if (!hasErrorResults()) myModuleChecker.checkModuleReference(statement);
     }
   }
 
@@ -650,6 +651,7 @@ final class JavaErrorVisitor extends JavaElementVisitor {
     super.visitPackageAccessibilityStatement(statement);
     if (JavaFeature.MODULES.isSufficient(myLanguageLevel)) {
       if (!hasErrorResults()) myModuleChecker.checkHostModuleStrength(statement);
+      if (!hasErrorResults()) myModuleChecker.checkDuplicateModuleReferences(statement);
     }
   }
 
@@ -659,6 +661,14 @@ final class JavaErrorVisitor extends JavaElementVisitor {
     if (!hasErrorResults()) checkPreviewFeature(statement);
   }
 
+  @Override
+  public void visitUsesStatement(@NotNull PsiUsesStatement statement) {
+    super.visitUsesStatement(statement);
+    if (JavaFeature.MODULES.isSufficient(myLanguageLevel)) {
+      if (!hasErrorResults()) myModuleChecker.checkServiceReference(statement.getClassReference());
+    }
+  }
+
   @Override
   public void visitImportModuleStatement(@NotNull PsiImportModuleStatement statement) {
     super.visitImportModuleStatement(statement);
diff --git a/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/ModuleChecker.java b/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/ModuleChecker.java
index 39f054c78a33..07f7765d69fe 100644
--- a/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/ModuleChecker.java
+++ b/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/ModuleChecker.java
@@ -17,6 +17,7 @@ import com.intellij.psi.util.PsiUtil;
 import com.intellij.psi.util.PsiUtilCore;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jps.model.java.JavaModuleSourceRootTypes;
 import org.jetbrains.jps.model.module.JpsModuleSourceRootType;
 
@@ -127,6 +128,20 @@ final class ModuleChecker {
     }
   }
 
+  void checkDuplicateModuleReferences(@NotNull PsiPackageAccessibilityStatement statement) {
+    Set<String> targets = new HashSet<>();
+    for (PsiJavaModuleReferenceElement refElement : statement.getModuleReferences()) {
+      String refText = refElement.getReferenceText();
+      PsiJavaModuleReference ref = refElement.getReference();
+      assert ref != null : statement;
+      if (!targets.add(refText)) {
+        boolean exports = statement.getRole() == PsiPackageAccessibilityStatement.Role.EXPORTS;
+        var kind = exports ? JavaErrorKinds.MODULE_DUPLICATE_EXPORTS_TARGET : JavaErrorKinds.MODULE_DUPLICATE_OPENS_TARGET;
+        myVisitor.report(kind.create(refElement));
+      }
+    }
+  }
+
   private static String qName(PsiJavaCodeReferenceElement ref) {
     return ref != null ? ref.getQualifiedName() : null;
   }
@@ -167,4 +182,52 @@ final class ModuleChecker {
       myVisitor.report(JavaErrorKinds.MODULE_OPENS_IN_WEAK_MODULE.create(statement, module));
     }
   }
-}
+
+  void checkServiceReference(@Nullable PsiJavaCodeReferenceElement refElement) {
+    if (refElement != null) {
+      PsiElement target = refElement.resolve();
+      if (!(target instanceof PsiClass psiClass)) {
+        myVisitor.report(JavaErrorKinds.REFERENCE_UNRESOLVED.create(refElement));
+      }
+      else if (psiClass.isEnum()) {
+        myVisitor.report(JavaErrorKinds.MODULE_SERVICE_ENUM.create(refElement, psiClass));
+      }
+    }
+  }
+
+  void checkModuleReference(@NotNull PsiRequiresStatement statement) {
+    PsiJavaModuleReferenceElement refElement = statement.getReferenceElement();
+    if (refElement != null) {
+      PsiJavaModuleReference ref = refElement.getReference();
+      assert ref != null : refElement.getParent();
+      PsiJavaModule target = ref.resolve();
+      if (target == null) {
+        reportUnresolvedJavaModule(refElement);
+        return;
+      }
+      PsiJavaModule container = (PsiJavaModule)statement.getParent();
+      if (target == container) {
+        myVisitor.report(JavaErrorKinds.MODULE_CYCLIC_DEPENDENCE.create(refElement, Set.of(container)));
+      }
+      else {
+        Collection<PsiJavaModule> cycle = JavaPsiModuleUtil.findCycle(target);
+        if (cycle.contains(container)) {
+          myVisitor.report(JavaErrorKinds.MODULE_CYCLIC_DEPENDENCE.create(refElement, cycle));
+        }
+      }
+    }
+  }
+
+  private void reportUnresolvedJavaModule(@NotNull PsiJavaModuleReferenceElement refElement) {
+    PsiJavaModuleReference ref = refElement.getReference();
+    assert ref != null : refElement.getParent();
+
+    ResolveResult[] results = ref.multiResolve(true);
+    switch (results.length) {
+      case 0 -> myVisitor.report(myVisitor.isIncompleteModel()
+                       ? JavaErrorKinds.REFERENCE_PENDING.create(refElement)
+                       : JavaErrorKinds.MODULE_NOT_FOUND.create(refElement));
+      case 1 -> myVisitor.report(JavaErrorKinds.MODULE_NOT_ON_PATH.create(refElement));
+      default -> {}
+    }
+  }}
diff --git a/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/errors/JavaErrorKinds.java b/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/errors/JavaErrorKinds.java
index 99ff5487b2ff..6371c4a6376a 100644
--- a/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/errors/JavaErrorKinds.java
+++ b/java/codeserver/highlighting/src/com/intellij/java/codeserver/highlighting/errors/JavaErrorKinds.java
@@ -1373,6 +1373,30 @@ public final class JavaErrorKinds {
       .withRange((module, file) -> getRange(module));
   public static final Parameterized<PsiPackageAccessibilityStatement, PsiJavaModule> MODULE_OPENS_IN_WEAK_MODULE =
     parameterized(PsiPackageAccessibilityStatement.class, PsiJavaModule.class, "module.opens.in.weak.module");
+  public static final Parameterized<PsiJavaCodeReferenceElement, PsiClass> MODULE_SERVICE_ENUM =
+    parameterized(PsiJavaCodeReferenceElement.class, PsiClass.class, "module.service.enum")
+      .withAnchor(ref -> requireNonNullElse(ref.getReferenceNameElement(), ref))
+      .withRawDescription((ref, cls) -> message("module.service.enum", cls.getName()));
+  public static final Simple<PsiJavaModuleReferenceElement> MODULE_NOT_FOUND =
+    error(PsiJavaModuleReferenceElement.class, "module.not.found")
+      .withHighlightType(JavaErrorHighlightType.WRONG_REF)
+      .withRawDescription(ref -> message("module.not.found", ref.getReferenceText()));
+  public static final Simple<PsiJavaModuleReferenceElement> MODULE_NOT_ON_PATH =
+    error(PsiJavaModuleReferenceElement.class, "module.not.on.path")
+      .withRawDescription(ref -> message("module.not.on.path", ref.getReferenceText()));
+  public static final Parameterized<PsiJavaModuleReferenceElement, Collection<PsiJavaModule>> MODULE_CYCLIC_DEPENDENCE =
+    error(PsiJavaModuleReferenceElement.class, "module.cyclic.dependence")
+      .<Collection<PsiJavaModule>>parameterized()
+      .withRawDescription(
+        (ref, modules) -> message("module.cyclic.dependence", modules.stream().map(PsiJavaModule::getName)
+          .sorted().collect(Collectors.joining(", "))));
+
+  public static final Simple<PsiJavaModuleReferenceElement> MODULE_DUPLICATE_EXPORTS_TARGET =
+    error(PsiJavaModuleReferenceElement.class, "module.duplicate.exports.target")
+      .withRawDescription(ref -> message("module.duplicate.exports.target", ref.getReferenceText()));
+  public static final Simple<PsiJavaModuleReferenceElement> MODULE_DUPLICATE_OPENS_TARGET =
+    error(PsiJavaModuleReferenceElement.class, "module.duplicate.opens.target")
+      .withRawDescription(ref -> message("module.duplicate.opens.target", ref.getReferenceText()));
 
   private static @NotNull <Psi extends PsiElement> Simple<Psi> error(
     @NotNull @PropertyKey(resourceBundle = JavaCompilationErrorBundle.BUNDLE) String key) {
diff --git a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightVisitorImpl.java b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightVisitorImpl.java
index da8697a08f2d..0f715d557f16 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightVisitorImpl.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightVisitorImpl.java
@@ -426,7 +426,19 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
     super.visitPackageAccessibilityStatement(statement);
     if (JavaFeature.MODULES.isSufficient(myLanguageLevel)) {
       if (!hasErrorResults()) add(ModuleHighlightUtil.checkPackageReference(statement, myFile));
-      if (!hasErrorResults()) ModuleHighlightUtil.checkPackageAccessTargets(statement, myErrorSink);
+    }
+  }
+
+  @Override
+  public void visitModuleReferenceElement(@NotNull PsiJavaModuleReferenceElement refElement) {
+    super.visitModuleReferenceElement(refElement);
+    PsiJavaModuleReference ref = refElement.getReference();
+    if (refElement.getParent() instanceof PsiPackageAccessibilityStatement && 
+        ref != null && ref.multiResolve(true).length == 0) {
+      String message = JavaErrorBundle.message("module.not.found", refElement.getReferenceText());
+      HighlightInfo.Builder info =
+        HighlightInfo.newHighlightInfo(HighlightInfoType.WARNING).range(refElement).descriptionAndTooltip(message);
+      add(info);
     }
   }
 
@@ -438,14 +450,6 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
     }
   }
 
-  @Override
-  public void visitUsesStatement(@NotNull PsiUsesStatement statement) {
-    super.visitUsesStatement(statement);
-    if (JavaFeature.MODULES.isSufficient(myLanguageLevel)) {
-      if (!hasErrorResults()) add(ModuleHighlightUtil.checkServiceReference(statement.getClassReference()));
-    }
-  }
-
   @Override
   public void visitProvidesStatement(@NotNull PsiProvidesStatement statement) {
     super.visitProvidesStatement(statement);
diff --git a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaErrorFixProvider.java b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaErrorFixProvider.java
index 3c3b2ab40349..f8e4ffcc9385 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaErrorFixProvider.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaErrorFixProvider.java
@@ -148,6 +148,19 @@ final class JavaErrorFixProvider {
     fix(MODULE_FILE_WRONG_LOCATION, error -> new MoveFileFix(error.psi().getContainingFile().getVirtualFile(),
                                                              error.context(), QuickFixBundle.message("move.file.to.source.root.text")));
     fix(MODULE_OPENS_IN_WEAK_MODULE, error -> removeModifierFix(error.context(), PsiModifier.OPEN));
+    fix(MODULE_DUPLICATE_EXPORTS_TARGET,
+        error -> myFactory.createDeleteFix(error.psi(), QuickFixBundle.message("delete.reference.fix.text")));
+    fix(MODULE_DUPLICATE_OPENS_TARGET,
+        error -> myFactory.createDeleteFix(error.psi(), QuickFixBundle.message("delete.reference.fix.text")));
+    multi(MODULE_NOT_ON_PATH, error -> {
+      PsiJavaModuleReference ref = error.psi().getReference();
+      if (ref != null) {
+        List<IntentionAction> registrar = new ArrayList<>();
+        myFactory.registerOrderEntryFixes(ref, registrar);
+        return registrar;
+      }
+      return List.of();
+    });
   }
 
   private void createStatementFixes() {
diff --git a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaModuleGraphUtil.java b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaModuleGraphUtil.java
index 38f4fd48242e..2866433b5e94 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaModuleGraphUtil.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/JavaModuleGraphUtil.java
@@ -11,7 +11,6 @@ import com.intellij.openapi.fileTypes.FileType;
 import com.intellij.openapi.fileTypes.FileTypeRegistry;
 import com.intellij.openapi.fileTypes.LanguageFileType;
 import com.intellij.openapi.module.Module;
-import com.intellij.openapi.module.ModuleManager;
 import com.intellij.openapi.module.ModuleUtilCore;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.roots.*;
@@ -19,7 +18,6 @@ import com.intellij.openapi.roots.libraries.Library;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.pom.java.JavaFeature;
 import com.intellij.psi.*;
-import com.intellij.psi.impl.PsiJavaModuleModificationTracker;
 import com.intellij.psi.impl.light.LightJavaModule;
 import com.intellij.psi.impl.source.resolve.JavaResolveUtil;
 import com.intellij.psi.search.GlobalSearchScope;
@@ -30,18 +28,14 @@ import com.intellij.psi.util.PsiUtilCore;
 import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.MultiMap;
-import com.intellij.util.graph.DFSTBuilder;
-import com.intellij.util.graph.Graph;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.jetbrains.annotations.Unmodifiable;
 
 import java.util.*;
 
 import static com.intellij.openapi.roots.DependencyScope.PROVIDED;
 import static com.intellij.psi.PsiJavaModule.JAVA_BASE;
-import static java.util.Objects.requireNonNullElse;
 
 public final class JavaModuleGraphUtil {
   private static final Set<String> STATIC_REQUIRES_MODULE_NAMES = Set.of("lombok");
@@ -72,15 +66,6 @@ public final class JavaModuleGraphUtil {
     return javaModule instanceof LightJavaModule ? null : javaModule;
   }
 
-  public static @NotNull Collection<PsiJavaModule> findCycle(@NotNull PsiJavaModule module) {
-    Project project = module.getProject();
-    List<Set<PsiJavaModule>> cycles = CachedValuesManager.getManager(project).getCachedValue(project, () ->
-      Result.create(findCycles(project),
-                    PsiJavaModuleModificationTracker.getInstance(project),
-                    ProjectRootModificationTracker.getInstance(project)));
-    return requireNonNullElse(ContainerUtil.find(cycles, set -> set.contains(module)), Collections.emptyList());
-  }
-
   public static boolean exports(@NotNull PsiJavaModule source, @NotNull String packageName, @Nullable PsiJavaModule target) {
     Map<String, Set<String>> exports = CachedValuesManager.getCachedValue(source, () ->
       Result.create(exportsMap(source), source.getContainingFile()));
@@ -208,60 +193,6 @@ public final class JavaModuleGraphUtil {
     return scope == PROVIDED;
   }
 
-  /*
-   * Looks for cycles between Java modules in the project sources.
-   * Library/JDK modules are excluded in an assumption there can't be any lib -> src dependencies.
-   * Module references are resolved "globally" (i.e., without taking project dependencies into account).
-   */
-  private static @Unmodifiable @NotNull List<Set<PsiJavaModule>> findCycles(@NotNull Project project) {
-    Set<PsiJavaModule> projectModules = new HashSet<>();
-    for (Module module : ModuleManager.getInstance(project).getModules()) {
-      ModuleRootManager moduleRootManager = ModuleRootManager.getInstance(module);
-      List<PsiJavaModule> descriptors = ContainerUtil.mapNotNull(moduleRootManager.getSourceRoots(true),
-                                                                 root -> findDescriptorByFile(root, project));
-      if (descriptors.size() > 2) return Collections.emptyList();  // aborts the process when there are incorrect modules in the project
-
-      if (descriptors.size() == 2) {
-        if (descriptors.stream()
-              .map(d -> getVirtualFile(d))
-              .filter(Objects::nonNull).count() < 2) {
-          return Collections.emptyList();
-        }
-        projectModules.addAll(descriptors);
-      }
-      if (descriptors.size() == 1) projectModules.add(descriptors.get(0));
-    }
-
-    if (!projectModules.isEmpty()) {
-      MultiMap<PsiJavaModule, PsiJavaModule> relations = MultiMap.create();
-      for (PsiJavaModule module : projectModules) {
-        for (PsiRequiresStatement statement : module.getRequires()) {
-          PsiJavaModuleReference ref = statement.getModuleReference();
-          if (ref != null) {
-            ResolveResult[] results = ref.multiResolve(true);
-            if (results.length == 1) {
-              PsiJavaModule dependency = (PsiJavaModule)results[0].getElement();
-              if (dependency != null && projectModules.contains(dependency)) {
-                relations.putValue(module, dependency);
-              }
-            }
-          }
-        }
-      }
-
-      if (!relations.isEmpty()) {
-        Graph<PsiJavaModule> graph = new ChameleonGraph<>(relations, false);
-        DFSTBuilder<PsiJavaModule> builder = new DFSTBuilder<>(graph);
-        Collection<Collection<PsiJavaModule>> components = builder.getComponents();
-        if (!components.isEmpty()) {
-          return ContainerUtil.map(components, elements -> new LinkedHashSet<>(elements));
-        }
-      }
-    }
-
-    return Collections.emptyList();
-  }
-
   private static @NotNull Map<String, Set<String>> exportsMap(@NotNull PsiJavaModule source) {
     Map<String, Set<String>> map = new HashMap<>();
     for (PsiPackageAccessibilityStatement statement : source.getExports()) {
@@ -272,37 +203,6 @@ public final class JavaModuleGraphUtil {
     return map;
   }
 
-  private static final class ChameleonGraph<N> implements Graph<N> {
-    private final Set<N> myNodes;
-    private final MultiMap<N, N> myEdges;
-    private final boolean myInbound;
-
-    private ChameleonGraph(MultiMap<N, N> edges, boolean inbound) {
-      myNodes = new HashSet<>();
-      edges.entrySet().forEach(e -> {
-        myNodes.add(e.getKey());
-        myNodes.addAll(e.getValue());
-      });
-      myEdges = edges;
-      myInbound = inbound;
-    }
-
-    @Override
-    public @NotNull Collection<N> getNodes() {
-      return myNodes;
-    }
-
-    @Override
-    public @NotNull Iterator<N> getIn(N n) {
-      return myInbound ? myEdges.get(n).iterator() : Collections.emptyIterator();
-    }
-
-    @Override
-    public @NotNull Iterator<N> getOut(N n) {
-      return myInbound ? Collections.emptyIterator() : myEdges.get(n).iterator();
-    }
-  }
-
   public static class JavaModuleScope extends GlobalSearchScope {
     private final @NotNull MultiMap<String, PsiJavaModule> myModules;
     private final boolean myIncludeLibraries;
diff --git a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/ModuleHighlightUtil.java b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/ModuleHighlightUtil.java
index 5850bc121cdd..41be5b9d3fe2 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/ModuleHighlightUtil.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/ModuleHighlightUtil.java
@@ -13,7 +13,6 @@ import com.intellij.codeInsight.intention.IntentionAction;
 import com.intellij.codeInsight.intention.QuickFixFactory;
 import com.intellij.java.codeserver.core.JavaServiceProviderUtil;
 import com.intellij.modcommand.ModCommandAction;
-import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.module.ModuleUtilCore;
 import com.intellij.openapi.roots.ModuleRootManager;
@@ -30,12 +29,9 @@ import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.JBIterable;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
 import java.util.function.Consumer;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 // generates HighlightInfoType.ERROR-like HighlightInfos for modularity-related (Jigsaw) problems
 final class ModuleHighlightUtil {
@@ -102,19 +98,16 @@ final class ModuleHighlightUtil {
       PsiJavaModuleReference ref = refElement.getReference();
       assert ref != null : refElement.getParent();
       PsiJavaModule target = ref.resolve();
-      if (target == null) return getUnresolvedJavaModuleReason(statement, refElement);
-      PsiJavaModule container = (PsiJavaModule)statement.getParent();
-      if (target == container) {
-        String message = JavaErrorBundle.message("module.cyclic.dependence", container.getName());
-        return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(refElement).descriptionAndTooltip(message);
-      }
-      else {
-        Collection<PsiJavaModule> cycle = JavaModuleGraphUtil.findCycle(target);
-        if (cycle.contains(container)) {
-          Stream<String> stream = cycle.stream().map(PsiJavaModule::getName);
-          if (ApplicationManager.getApplication().isUnitTestMode()) stream = stream.sorted();
-          String message = JavaErrorBundle.message("module.cyclic.dependence", stream.collect(Collectors.joining(", ")));
-          return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(refElement).descriptionAndTooltip(message);
+      if (target == null) {
+        PsiJavaModuleReference ref1 = refElement.getReference();
+        assert ref1 != null : refElement.getParent();
+
+        ResolveResult[] results = ref1.multiResolve(true);
+        if (results.length > 1) {
+          // TODO: make as error or extract to inspection
+          return HighlightInfo.newHighlightInfo(HighlightInfoType.WARNING)
+            .range(refElement)
+            .descriptionAndTooltip(JavaErrorBundle.message("module.ambiguous", refElement.getReferenceText()));
         }
       }
     }
@@ -203,44 +196,6 @@ final class ModuleHighlightUtil {
     }
   }
 
-  static void checkPackageAccessTargets(@NotNull PsiPackageAccessibilityStatement statement,
-                                        @NotNull Consumer<? super HighlightInfo.Builder> errorSink) {
-    Set<String> targets = new HashSet<>();
-    for (PsiJavaModuleReferenceElement refElement : statement.getModuleReferences()) {
-      String refText = refElement.getReferenceText();
-      PsiJavaModuleReference ref = refElement.getReference();
-      assert ref != null : statement;
-      if (!targets.add(refText)) {
-        boolean exports = statement.getRole() == Role.EXPORTS;
-        String message = JavaErrorBundle.message(exports ? "module.duplicate.exports.target" : "module.duplicate.opens.target", refText);
-        HighlightInfo.Builder info = createDuplicateReference(refElement, message);
-        errorSink.accept(info);
-      }
-      else if (ref.multiResolve(true).length == 0) {
-        String message = JavaErrorBundle.message("module.not.found", refElement.getReferenceText());
-        HighlightInfo.Builder info =
-          HighlightInfo.newHighlightInfo(HighlightInfoType.WARNING).range(refElement).descriptionAndTooltip(message);
-        errorSink.accept(info);
-      }
-    }
-  }
-
-  static HighlightInfo.Builder checkServiceReference(@Nullable PsiJavaCodeReferenceElement refElement) {
-    if (refElement != null) {
-      PsiElement target = refElement.resolve();
-      if (!(target instanceof PsiClass psiClass)) {
-        String message = JavaErrorBundle.message("cannot.resolve.symbol", refElement.getReferenceName());
-        return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(range(refElement)).descriptionAndTooltip(message);
-      }
-      else if (psiClass.isEnum()) {
-        String message = JavaErrorBundle.message("module.service.enum", psiClass.getName());
-        return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(range(refElement)).descriptionAndTooltip(message);
-      }
-    }
-
-    return null;
-  }
-
   static void checkServiceImplementations(@NotNull PsiProvidesStatement statement, @NotNull PsiFile file,
                                           @NotNull Consumer<? super HighlightInfo.Builder> errorSink) {
     PsiReferenceList implRefList = statement.getImplementationList();