void (@NotNull PsiLiteralExpression expression) { super.visitLiteralExpression(expression); final PsiType type = expression.getType(); if (!TypeUtils.isJavaLangString(type)) { return; } final String value = (String)expression.getValue(); if (value == null || value.length() != 1) { return; } if (ExpressionUtils.isConversionToStringNecessary(expression, false)) { return; } registerError(expression, value); }