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test_assignment.sol

pragma solidity >=0.4.0 <0.6.0;
contract C {
    uint[] x;
    // the data location of x is storage
    // the data location of memoryArray is memory
    function f(uint[] memory memoryArray) public{
        x = memoryArray; // works, copies the whole array to storage
        uint[] storage y = x; // works, assigns a pointer, data location of y is storage
        //y[7]; // fine, returns the 8th element
        //y.length = 2;   // fine, modifies x through y
        //delete x;   // fine, clears the array, also modifies y
        // The following does not work; it would need to create a new temporary /
        // unnamed array in storage, but storage is "statically" allocated:
        // y = memoryArray;
        // This does not work either, since it would "reset" the pointer, but there
        // is no sensible location it could point to.
        // delete y;
        g(x);
        // calls g, handing over a reference to x
        h(x);
        // calls h and creates an independent, temporary copy in memory
    }
    function g(uint[] storage) internal pure{}
    function h(uint[] memory) public pure{}
}