The following code does not compile and I don't understand why.

import std.stdio;

class Data
{
    string m = "Hello world !";
}

struct IdxElem(D)
{
    bool inUse;
    D data;
}
IdxElem!Data[string] idx;


void main()
{
    idx["test1"] = IdxElem(true, new Data);
    idx["test2"] = IdxElem(false, new Data);

    writeln(idx["test2"].data);
    writeln("Hello world!");
}

This is the error message I get with DMD64 D Compiler v2.068.2

source/app.d(20,27): Error: struct app.IdxElem cannot deduce function from argument types !()(bool, Data), candidates are:
source/app.d(9,1):        app.IdxElem(D)
source/app.d(21,27): Error: struct app.IdxElem cannot deduce function from argument types !()(bool, Data), candidates are:
source/app.d(9,1):        app.IdxElem(D)
dmd failed with exit code 1.

I get the same error even if I add a constructor to IdxElem that sets the member variables with its two arguments.

Oops! Stupid of me. There were three bugs in the code.

Correct code is as follow:


import std.stdio;

class Data
{
    string m = "Hello world !";
}

struct IdxElem(D)
{
    bool inUse;
    D data;
}

IdxElem!(Data)[string] idx;


void main()
{
    idx["test1"] = IdxElem!Data(true, new Data);
    idx["test2"] = IdxElem!Data(false, new Data);

    writeln(idx["test2"].data.m);
    writeln("Hello world!");
}