fix Issue 21880 - [REG 2.095] scope variable assigned to non-scope parameter calling function

[ibuclaw]

Propagate scope from the parameter to the temporary that is being created for it.

However... it does seem suspect that a temporary is being created for a type that doesn't need it, just because another parameter needs destruction.

The inverse of this fix would be to constrain needsPrefix to not be true for trivial/pod types, or scope parameters.

[dlang-bot]

Thanks for your pull request, @ibuclaw!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	21880	regression	[REG 2.095] scope variable assigned to non-scope parameter calling function

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "stable + dmd#12493"

[kinke]

However... it does seem suspect that a temporary is being created for a type that doesn't need it, just because another parameter needs destruction.

It's about strict left-to-right evaluation order of arguments. foo(makeTemporaryWithDtor(), makePODWithSideEffects(), mightThrow(), 123) => makePODWithSideEffects() must be evaluated as 2nd expression.

[ibuclaw]

However... it does seem suspect that a temporary is being created for a type that doesn't need it, just because another parameter needs destruction.

It's about strict left-to-right evaluation order of arguments. foo(makeTemporaryWithDtor(), makePODWithSideEffects(), mightThrow(), 123) => makePODWithSideEffects() must be evaluated as 2nd expression.

An argument with side effects is justifiable, a pointer or string less so.

[ibuclaw]

Oops, I committed on top of stable, but for some reason this PR is targeting master.

[ibuclaw]

This caused a regression. :-(
https://issues.dlang.org/show_bug.cgi?id=22084