https://issues.dlang.org/show_bug.cgi?id=12247

Simon Naarmann <eiderdaus@gmail.com> changed:

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           Keywords|                            |contracts
                 CC|                            |eiderdaus@gmail.com

--- Comment #1 from Simon Naarmann <eiderdaus@gmail.com> ---
This issue still exists in DMD 2.084.1, tested on Linux 64-bit.

In the example code, the interface's in contract should throw, but does not. Only the out contract throws as desired.

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https://issues.dlang.org/show_bug.cgi?id=12247

Simon Naarmann <eiderdaus@gmail.com> changed:

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                 OS|Mac OS X                    |All

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https://issues.dlang.org/show_bug.cgi?id=12247

Iain Buclaw <ibuclaw@gdcproject.org> changed:

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           Priority|P2                          |P3

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https://issues.dlang.org/show_bug.cgi?id=12247

Dennis <dkorpel@live.nl> changed:

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             Status|NEW                         |RESOLVED
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         Resolution|---                         |DUPLICATE

--- Comment #2 from Dennis <dkorpel@live.nl> ---
This is working as designed, though it is somewhat controversial.

> The fundamental nature of 'in' contracts is that they are "loosened" on derivation. If an instance of B is passed to parameter A, then if either the contract for A or the contract for B passes, then it passes. It is NOT necessary for the A contract to pass.

See issue 6856

*** This issue has been marked as a duplicate of issue 6856 ***

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https://issues.dlang.org/show_bug.cgi?id=12247

--- Comment #3 from Simon Naarmann <eiderdaus@gmail.com> ---
Ah, I wouldn't have guessed that absence of contract means an always-passing contract. Thanks!

I agree to close it as a duplicate of 6856.

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https://issues.dlang.org/show_bug.cgi?id=12247

FeepingCreature <default_357-line@yahoo.de> changed:

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                 CC|                            |default_357-line@yahoo.de

--- Comment #4 from FeepingCreature <default_357-line@yahoo.de> ---
Note that in theory there's `-preview=inclusiveincontracts`, which changes the way inconditions work to require (at runtime) that child in-contracts are a subset of parent in-contracts. Though I haven't worked on it for a while now, because we've generally reduced the amount of objects being passed to functions (or non-autogenerated methods), so it hasn't come up in a while.

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https://issues.dlang.org/show_bug.cgi?id=12247

--- Comment #5 from FeepingCreature <default_357-line@yahoo.de> ---
Hm, apologies, nevermind - that seems unrelated.

Right now, "no in-contract" is equivalent to "in (true)".

`I::foo(int i) in (i > 7)` creates an in-contract of "at least i > 7 must be
permitted for foo".
`Impl::foo(int i)` has no additional in-contract, so it allows in all values,
causing the behavior in this bug report.

preview=inclusiveincontracts does not affect this. The only thing it would affect is if you wrote `Impl::foo(int i) in (false)`, which today would succeed if called with, say, `8`, because 8 would pass the interface in-contract, and it only has to pass the in-contract of any of the override parents (because they are implicitly inclusive). But `in (true)`, which writing no in-contract implicitly is, works with either behavior.

Sorry for the spam, feel free to delete both comments.

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