• d-bugmail puremagic.com (40/40) Feb 25 2023 https://issues.dlang.org/show_bug.cgi?id=23740

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=23740

          Issue ID: 23740
           Summary: Alias breaks valid array operation code using operator
                    overloading
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: HuskyNator protonmail.ch

When an alias introduces a potential array, it's picked over a valid overloaded
operator when doing an array operation, causing a compilation error.

When the alias is removed, this code compiles and functions properly:

struct Vec{
    int[2] list;
    alias list this; // Causes failing compilation (c[]*b has b cast to
int[2]).

    Vec opBinary(string op)(const Vec rhs) const {
        Vec newA;
        mixin("newA.list[0] = list[0]"~op~"rhs.list[0];");
        mixin("newA.list[1] = list[1]"~op~"rhs.list[1];");
        return newA;
    }
}

void main(string[]) {
    Vec a;
    a.list = [1,1];
    Vec b;
    b.list = [2,2];

    Vec[2] c = [a, b];
    Vec[2] d;
    d[] = c[] * b;
    writeln(d);
}

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