Return in the body of a foreach in a constructor backed by opApply corrupts the object

[dlangBugzillaToGithub]

André Puel reported this on 2016-08-31T17:45:38Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=16454

CC List

• ag0aep6g

Description

import std.stdio;

struct OpApply {
    int opApply(int delegate(int) cb) {
        return cb(42);
    }
}

struct Bolinha {
    int a;
    this(ref OpApply moviadao) {
        foreach(int b; moviadao) {
            this.a = b;
            return;
        }
    }
};

void main() {
    import std.stdio;

    OpApply range;
    writeln(Bolinha(range).a);
}

The expected print result was 42. But I get a random memory garbage instead. The following minor modification in main will 'fix' the issue:

void main() {
    import std.stdio;

    OpApply range;
    Bolinha littleBall = Bolinha(range);
    writeln(littleBall.a);
}

[dlangBugzillaToGithub]

ag0aep6g commented on 2016-08-31T18:14:51Z

Slightly reduced:

----
struct OpApply {
    int opApply(int delegate(int) cb) { return 0; }
}

struct Bolinha {
    int a = 0;
    this(int dummy) {
        OpApply moviadao;
        foreach(int b; moviadao) return;
    }
}

void main() {
    import std.stdio;
    writeln(Bolinha(0).a);
}
----

Also fails on Linux and Windows (wine).

[dlangBugzillaToGithub]

moonlightsentinel commented on 2021-10-26T13:19:53Z

Works reliably since 2.094.1 according to run.dlang.io / local tests