Bug 6453 – Allow multiple invariant per struct/class

I would like to use a template mixin to add some fields to a struct, but I'd also like the template to add additional invariant checks without having to remember to add this for all struct/classes that mixes in this code. class C { int a; } mixin template EmbedC() { C _c; // oops.. more than one invariant invariant() { assert(_c); } void close() { _c = null; } } struct S { int i = 10; invariant() { assert(i >= 10); } mixin EmbedC!(); } void main() { S s; s.close(); s._c.a = 10; // access violation, but I want assertion from invariant }

The spec explicitly states that there can only be one invariant, so this is an enhancement. On the other hand, this appears to be an arbitrary restriction.

I completely agree with this change; I ran into this exact limitation for the exact same scenario as well. It's rather crippling for template mixins. While on this topic, see also bug #5038. It would be a natural extension of this enhancement IMHO.

*** Issue 5038 has been marked as a duplicate of this issue. ***

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/ae70bfdeafd3a534e3f12747503bafa046be2f9d fix Issue 6453 - Allow multiple invariant per struct/class https://github.com/D-Programming-Language/dmd/commit/081c92a115b3006871c5a516267417e06ceacbcf Merge pull request #1978 from 9rnsr/multi_inv Issue 6453 - Allow multiple invariant per struct/class

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/ce58435fe322afd736504f804bdad6a9debb8c1d Fix up for issue 6453 change, allow shared/synchronized invariants But mixing non-shared/shared/synchronized is currently rejected. https://github.com/D-Programming-Language/dmd/commit/4fbc77fa504c2d8ee4c7ef10edc70221a74742c3 Merge pull request #2028 from 9rnsr/multi_inv Fix up for issue 6453 change, allow shared/synchronized invariants

Commits pushed to master at https://github.com/dlang/dlang.org https://github.com/dlang/dlang.org/commit/6303d28d7201f048cb4550b4f875710dd8bde6c3 Update spec after issue 6453 See https://issues.dlang.org/show_bug.cgi?id=6453 https://github.com/dlang/dlang.org/commit/672783b8ffd4fc6d19bfb9da0d3d0ce23323c312 Merge pull request #1287 from JohanEngelen/patch-4 Update spec after issue 6453

Commits pushed to stable at https://github.com/dlang/dlang.org https://github.com/dlang/dlang.org/commit/6303d28d7201f048cb4550b4f875710dd8bde6c3 Update spec after issue 6453 https://github.com/dlang/dlang.org/commit/672783b8ffd4fc6d19bfb9da0d3d0ce23323c312 Merge pull request #1287 from JohanEngelen/patch-4