尝试调用默认构造函数时，没有匹配的构造函数

Question

In my code I have a class with following structure:

 struct AutomatonNode {
    ...
    AutomatonNode();
    AutomatonNode(AutomatonNode &node);
    ...
};

Default constructor has following realisation:

AutomatonNode::AutomatonNode() :
    suffixLink(-1),
    len(0) {};

However, during compilation I get the following error:

No matching constructor for initialization of 'SA::AutomatonNode'

in this method:

size_t SuffixAutomaton::newState() {
    AutomatonNode node;
    nodes.push_back(node);
    return nodes.size() - 1;
}

Looks extremely strange to me, since everything is in place and the constructor is public(it's a struct and by default all fields are public). Any ideas?

For clearance:

Apple LLVM version 7.3.0 (clang-703.0.31)

Target: x86_64-apple-darwin15.3.0

Thread model: posix

Answer 1

The error has nothing to do with default constructor. (What made you think it did?)

The problem is most likely caused by your copy constructor accepting its argument as non-const reference. (It is impossible to say for sure since you provided no information about what nodes is.) If nodes is a standard container, then standard push_back accepts its argument as a reference to const. Such argument cannot be passed to your copy constructor. Hence the error.