• d-bugmail puremagic.com (45/45) Mar 11 2022 https://issues.dlang.org/show_bug.cgi?id=22870

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=22870

          Issue ID: 22870
           Summary: __traits(parent) with opApply returns generated
                    delegate instead of lexical parent
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: snarwin+bugzilla gmail.com

As of DMD 2.099.0, the following program fails to compile:

---
struct HasOpApply
{
    int opApply(int delegate(int) dg)
    {
        if (int result = dg(0)) return result;
        return 0;
    }
}

void main()
{
    foreach (x; 0 .. 1)
    {
        // ok
        static assert(__traits(identifier, __traits(parent, {})) == "main");
    }

    foreach (x; HasOpApply())
    {
        // error
        static assert(__traits(identifier, __traits(parent, {})) == "main");
    }
}
---

The error is:

---
onlineapp.d(21): Error: static assert:  `"__foreachbody5" == "main"` is false
---

This happens because __traits(parent) is evaluated after the compiler has
transformed the foreach loop into a call to HasOpApply.opApply.

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