Bug 17590 – Unnecessary GC alloc on returning static local struct

The following code does not compile: ``` auto foo(int a, bool b) @nogc { static struct SInside {} SInside res; lazyfun(a); return res; } void lazyfun(scope lazy int a) @nogc; ``` Because the return type is a local struct, the frontend thinks a GC allocated closure is needed. But, the local struct is static, so no reference to the local frame and a closure is not needed.

Commits pushed to master at https://github.com/dlang/dmd https://github.com/dlang/dmd/commit/9940f4ce5e82f783b3c41c260c32b56b11e37f8a Fix Issue 17590 - Unnecessary GC alloc on returning static local struct https://github.com/dlang/dmd/commit/c3c8a71e085c16d56a359d5007590e4737292ee4 Merge pull request #6963 from JohanEngelen/closurenonstatic Fix Issue 17590 - Unnecessary GC alloc on returning static local struct merged-on-behalf-of: Sebastian Wilzbach <[email protected]>

Commits pushed to newCTFE at https://github.com/dlang/dmd https://github.com/dlang/dmd/commit/9940f4ce5e82f783b3c41c260c32b56b11e37f8a Fix Issue 17590 - Unnecessary GC alloc on returning static local struct https://github.com/dlang/dmd/commit/c3c8a71e085c16d56a359d5007590e4737292ee4 Merge pull request #6963 from JohanEngelen/closurenonstatic

Commits pushed to stable at https://github.com/dlang/dmd https://github.com/dlang/dmd/commit/9940f4ce5e82f783b3c41c260c32b56b11e37f8a Fix Issue 17590 - Unnecessary GC alloc on returning static local struct https://github.com/dlang/dmd/commit/c3c8a71e085c16d56a359d5007590e4737292ee4 Merge pull request #6963 from JohanEngelen/closurenonstatic