[Issue 24374] ImportC: .di generator incorrect output for anonymous structs as members

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24374

Derek Fawcus <dfawcus+dlang at employees.org> changed:

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                 CC|                            |dfawcus+dlang at employees.org

--- Comment #1 from Derek Fawcus <dfawcus+dlang at employees.org> ---
I just ran in to exactly this issue while evaluating the potential for adding D
(betterC mode) code to an existing C project, as an alternative to adding Rust
code.

For that I needed to be able to annotate existing functions with @nogc and
nothrow, however the basic import of a C file does not allow for this. 

As such I decided to generate a .di file using this mechanism, and manipulate
the file, prepending the annotations.  Then I ran in to this issue.

While I could work around this by altering my source files adding tags such
that the struct / union is no longer anonymous, that is not viable.  One reason
being the quantity of changes required.

More significantly the project headers in question transitively included system
headers (inttypes.h) which themselves resulted in the same problem, as those
system headers had similar anonymous structs and unions.  Having to edit these
is a non starter.

There was another reason for wishing to pre-process the C headers to .di files,
that being efficiency.  By doing so, it would avoid the D compiler from having
to repeatedly parse/transform the complete C sources, making builds faster.

As it stands, the lack of ability to control the annotation (@nogc, nothrow,
etc) applied to C sources so imported rather makes the use of ImportC and
BetterC as I envisaged impractical.

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