Re: mixin template and const property qualifier?

[anonymous via Digitalmars-d-learn]

On Monday, 15 December 2014 at 23:14:30 UTC, aldanor wrote:

Could someone please explain why the following doesn't compile with "const" qualifier while it does work without it?

/* test.d */

module test;

mixin template Foo() {
    mixin("@property int bar() const { return foo; }");
}

int foo = 1;

mixin Foo;

unittest {
    assert(foo == bar);
}

rdmd -main -unittest test.d

test.d-mixin-4(4): Error: function test.Foo!().bar without 'this' cannot be const

test.d(9): Error: mixin test.Foo!() error instantiating

Has nothing to do with mixin. This produces the same error
message:

@property int bar() const { return foo; }
int foo = 1;
unittest {assert(foo == bar);}

The thing is, free functions cannot be const. In a const method,
what's const is `this`. A free function doesn't have `this`, so
it cannot be const.