IDEA-154289 PsiClass and view provider can never agree on language

java/java-psi-impl/src/com/intellij/psi/ClassFileViewProvider.java

@@ -16,6 +16,8 @@
 package com.intellij.psi;
 
 import com.intellij.ide.highlighter.JavaClassFileType;
+import com.intellij.lang.Language;
+import com.intellij.lang.java.JavaLanguage;
 import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.fileTypes.FileType;
@@ -51,6 +53,12 @@ public class ClassFileViewProvider extends SingleRootFileViewProvider {
     super(manager, file, eventSystemEnabled, JavaClassFileType.INSTANCE);
   }
 
+  @NotNull
+  @Override
+  public Language getBaseLanguage() {
+    return JavaLanguage.INSTANCE;
+  }
+
   @Override
   protected PsiFile createFile(@NotNull Project project, @NotNull VirtualFile file, @NotNull FileType fileType) {
     FileIndexFacade fileIndex = ServiceManager.getService(project, FileIndexFacade.class);

java/java-tests/testSrc/com/intellij/psi/ClsPsiTest.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.psi;
 
+import com.intellij.lang.java.JavaLanguage;
 import com.intellij.openapi.application.ex.PathManagerEx;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.util.io.IoTestUtil;
@@ -100,6 +101,12 @@ public class ClsPsiTest extends LightIdeaTestCase {
     assertFalse(aClass.isDeprecated());
   }
 
+  public void testViewProviderHasJavaLanguage() {
+    PsiJavaFile file = getFile("MyClass");
+    assertEquals(JavaLanguage.INSTANCE, file.getLanguage());
+    assertEquals(JavaLanguage.INSTANCE, file.getViewProvider().getBaseLanguage());
+  }
+
   public void testClassMembers() {
     PsiClass aClass = getFile("MyClass").getClasses()[0];
 

platform/core-impl/src/com/intellij/psi/SingleRootFileViewProvider.java

@@ -293,12 +293,12 @@ public class SingleRootFileViewProvider extends UserDataHolderBase implements Fi
   }
 
   public List<PsiFile> getCachedPsiFiles() {
-    return ContainerUtil.createMaybeSingletonList(getCachedPsi(myBaseLanguage));
+    return ContainerUtil.createMaybeSingletonList(getCachedPsi(getBaseLanguage()));
   }
 
   @NotNull
   public List<FileElement> getKnownTreeRoots() {
-    PsiFile psiFile = getCachedPsi(myBaseLanguage);
+    PsiFile psiFile = getCachedPsi(getBaseLanguage());
     if (!(psiFile instanceof PsiFileImpl)) return Collections.emptyList();
     FileElement element = ((PsiFileImpl)psiFile).getTreeElement();
     return ContainerUtil.createMaybeSingletonList(element);
@@ -457,7 +457,7 @@ public class SingleRootFileViewProvider extends UserDataHolderBase implements Fi
   @NotNull
   @Override
   public SingleRootFileViewProvider createCopy(@NotNull final VirtualFile copy) {
-    return new SingleRootFileViewProvider(getManager(), copy, false, myBaseLanguage);
+    return new SingleRootFileViewProvider(getManager(), copy, false, getBaseLanguage());
   }
 
   @Override
@@ -572,7 +572,7 @@ public class SingleRootFileViewProvider extends UserDataHolderBase implements Fi
   }
 
   public void markInvalidated() {
-    PsiFile psiFile = getCachedPsi(myBaseLanguage);
+    PsiFile psiFile = getCachedPsi(getBaseLanguage());
     if (psiFile instanceof PsiFileEx) {
       ((PsiFileEx)psiFile).markInvalidated();
     }