• via Digitalmars-d-bugs (51/51) Sep 25 2014 https://issues.dlang.org/show_bug.cgi?id=13531

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=13531

          Issue ID: 13531
           Summary: Destructor attributes don't take member destructor
                    attributes into account
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: DMD
          Assignee: nobody puremagic.com
          Reporter: monarchdodra gmail.com

If you have "S" with completely unsafe destructor, and you aggregate it into
"SS":

//----
struct S
{
    ~this() //not nothrow, system, impure, gc etc...
    {}
}

struct SS
{
    S s;
    ~this()  safe pure nothrow  nogc
    {}
}
//----

This compiles. This may or may not be wrong, depending on your point of view:
The "code content" of the destructor is indeed actually safe etc...

The issue comes if you actually do try to use it in a safe context:

//----
void main()  safe pure nothrow  nogc
{
    SS ss;
}
//----

Here is the error message:
//----
Error: pure function 'D main' cannot call impure function 'main.SS.~this'
Error: safe function 'D main' cannot call system function 'main.SS.~this'
Error:  nogc function 'D main' cannot call non- nogc function 'main.SS.~this'
Error: 'main.SS.~this' is not nothrow
Error: function 'D main' is nothrow yet may throw
//----

The issue here is that it clearly states that "SS.~this" is the one that is
unsafe, yet it is clearly marked as such.

IMO, the bug is that it should have never been legally marked as  safe to begin
with.

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