[Issue 13531] Destructor attributes don't take member destructor attributes into account

[d-bugmail at puremagic.com]

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

Stanislav Blinov <stanislav.blinov at gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |stanislav.blinov at gmail.com

--- Comment #2 from Stanislav Blinov <stanislav.blinov at gmail.com> ---
Nowadays the error message is... better, for a conservative definition of
"better". But it's __very__ verbose and most of all, wrong. It's referring to
SS.~this, which is not at all the destructor in question - SS.__xdtor is. It's
even referring to the line where SS.~this is declared! SS.~this has the
attributes, and the error message shouldn't indicate that it doesn't.

main.d(16): Error: `pure` function `D main` cannot call impure destructor
`SS.~this`
main.d(10):        generated `SS.~this` is impure because of the following
field's destructors:
main.d(9):         - S s
main.d(3):           impure `S.~this` is declared here
main.d(16): Error: `@safe` function `D main` cannot call `@system` destructor
`SS.~this`
main.d(10):        `SS.~this` is declared here
main.d(10):        generated `SS.~this` is @system because of the following
field's destructors:
main.d(9):         - S s
main.d(3):           @system `S.~this` is declared here
main.d(16): Error: `@nogc` function `D main` cannot call non- at nogc destructor
`SS.~this`
main.d(10):        generated `SS.~this` is non- at nogc because of the following
field's destructors:
main.d(9):         - S s
main.d(3):           non- at nogc `S.~this` is declared here
main.d(16): Error: destructor `SS.~this` is not `nothrow`
main.d(10):        generated `SS.~this` is not nothrow because of the following
field's destructors:
main.d(9):         - S s
main.d(3):           not nothrow `S.~this` is declared here
main.d(14): Error: `nothrow` function `D main` may throw

Add more fields to SS, and this gets even longer.

With this code:

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

struct S2
{
    ~this() {}
}

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

struct SSS
{
    SS ss;
    ~this() @safe pure nothrow @nogc {}
}

void main() @safe pure nothrow @nogc
{
    SSS ss;
}

...errors are page long :\

Suggested change:

main.d(16): Error: `@safe pure nothrow @nogc` function `D main` cannot call
impure @system throwing GC-using generated destructor for `SS`
main.d(9): Generated destructor for `SS` is impure @system throwing GC-using
because of destructor of field `s`
main.d(3): impure @system throwing GC-using destructor of field `s` is declared
here

...with one relevant line per field, correctly distinguishing generated
destructors and user-defined destructors.

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