DiffRequest (@NotNull PsiElement psiElement1, @NotNull PsiElement psiElement2) { if (!psiElement1.isValid() || !psiElement2.isValid()) return null; Project project = psiElement1.getProject(); LOG.assertTrue(project == psiElement2.getProject()); DiffContent content1 = fromPsiElement(psiElement1); DiffContent content2 = fromPsiElement(psiElement2); if (content1 == null || content2 == null) return null; final ElementPresentation presentation1 = ElementPresentation.forElement(psiElement1); final ElementPresentation presentation2 = ElementPresentation.forElement(psiElement2); String title = DiffBundle .message("diff.element.qualified.name.vs.element.qualified.name.dialog.title", presentation1.getQualifiedName(), presentation2.getQualifiedName()); return new SimpleDiffRequest(title, content1, content2, presentation1.getQualifiedName(), presentation2.getQualifiedName()); }