void (@NotNull PsiMethod method, int argumentIdx, @NotNull Processor<? super PsiExpression> nullArgumentProcessor, Collection<? extends VirtualFile> candidateFiles) { if (candidateFiles.isEmpty()) return; GlobalSearchScope scope = GlobalSearchScope.filesScope(method.getProject(), candidateFiles); MethodReferencesSearch.search(method, scope, true).forEach(ref -> { PsiExpression argument = getCallArgument(ref, argumentIdx); if (argument instanceof PsiLiteralExpression && argument.textMatches(PsiKeyword.NULL)) { return nullArgumentProcessor.process(argument); } return true; }); }