Incomprehensible errors while trying to return a pair of nodes in a templated BST class in C++

Question

I am trying to make a BST data structure, in it a method searchUtil(T x) finds the node having data x, and returns its address, and the address of its parent in a 'pair' object. Without templating, the method works fine. This is the code:

#include<iostream>
using namespace std;

template<typename T>
class BST{
public:
    struct node{
        T data;
        node *left, *right;
        node(T _data):data(_data){
            left = right = NULL;
        }
        node():data(){
            left = right = NULL;
        }
    };

    node* root;
    long long int _size;

    BST(){root=NULL;_size=0;}

    std::pair<node*, node*> searchUtil(T);
};


template<typename T>
typename std::pair<BST<T>::node*, BST<T>::node*> BST<T>::searchUtil(T x){  
    node *cur = root, *trail = NULL;         
    while(cur != NULL){                      
        if(cur->data < x){
            trail = cur;
            cur = cur->right;

        }else if(cur->data > x){
            trail = cur;
            cur = cur->left;

        }else{
            break;
        }
    }
    return pair<node*,node*> (cur, trail);
}

I have tried to change the code to remove the errors, but to no merit.

The errors are:

||=== Build: Debug in testBench (compiler: GNU GCC Compiler) ===|
error: type/value mismatch at argument 1 in template parameter list for 'template<class _T1, class _T2> struct std::pair'|
error:   expected a type, got '(BST<T>::node * <expression error>)'|
error: template argument 2 is invalid|
error: 'BST' in namespace 'std' does not name a template type|
error: expected unqualified-id before '<' token|
||=== Build failed: 5 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|

And I cannot make anything of them. Any insight to why this is happening would be greatly helpful.

I am also confused by how if I don't write BST<T>::node* and simply write node*, I would get an error of node not being defined