don't highlight if psi was invalidated (EA-56385 - PIEAE: PsiUtilCore.ensureValid)

platform/analysis-impl/src/com/intellij/codeHighlighting/TextEditorHighlightingPass.java

@@ -74,7 +74,7 @@ public abstract class TextEditorHighlightingPass implements HighlightingPass {
     return myDumb;
   }
 
-  private boolean isValid() {
+  protected boolean isValid() {
     if (isDumbMode() && !DumbService.isDumbAware(this)) {
       return false;
     }

platform/analysis-impl/src/com/intellij/codeInsight/daemon/impl/ProgressableTextEditorHighlightingPass.java

@@ -72,6 +72,11 @@ public abstract class ProgressableTextEditorHighlightingPass extends TextEditorH
     return impl;
   }
 
+  @Override
+  protected boolean isValid() {
+    return super.isValid() && (myFile == null || myFile.isValid());
+  }
+
   private void sessionFinished() {
     advanceProgress(Math.max(1, myProgressLimit - myProgressCount.get()));
   }