https://issues.dlang.org/show_bug.cgi?id=13586

          Issue ID: 13586
           Summary: Destructors not run when argument list evaluation
                    throws
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: blocker
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: bugzilla@digitalmars.com

The following test case illustrates it - only s should be constructed, and when throwit() throws, it should be destructed. It isn't.

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import core.stdc.stdio;

struct S {
    static int count;
    ~this() { ++count; }
}

int throwit() { throw new Exception("whatevah"); }

void neverland(S s, int x, S t) { }

void main() {
    try {
        neverland(S(), throwit(), S());
    }
    catch (Exception e) {
        printf("%d\n", S.count);
        assert(S.count == 1);
    }
}

C:\cbx\mars>foo
0
core.exception.AssertError@foo.d(19): Assertion failure

-----------------------------------------------
The fix is similar to what Kenji did to ensure left to right order of evaluation of arguments. If any arguments have destructors, then the argument list has to be constructed before attempting to put the argument list on the stack, because destructing them on a partially built stack is problematic. The arguments are then blitted to the stack, because the blit operation cannot throw.

Note that this solution relies on D's requirement that a struct instance cannot have internal pointers to itself.

This bug blocks a reliable ref counting implementation.

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