boolean (@Nullable PsiExpression expression) { if (expression instanceof PsiLiteral) { return true; } if (expression instanceof PsiReferenceExpression) { PsiElement qualifier = ((PsiReferenceExpression)expression).getQualifier(); if (qualifier instanceof PsiQualifiedExpression || !(qualifier instanceof PsiExpression)) { PsiElement resolved = ((PsiReferenceExpression)expression).resolve(); return resolved instanceof PsiVariable || resolved instanceof PsiClass; } } return false; }