What does 'inline' mean?

[Steven Schveighoffer]

On 6/8/20 2:14 AM, Manu wrote:
> 3. I want to treat the function like an AST macro; I want the function 
> inserted at the callsite, and I want to have total confidence in this 
> mechanic. [This is about articulate mechanical control over code-gen; 
> ie, I know necessary facts about the execution context/callstack that I 
> expect to maintain]

This is my main use case. Not because I want AST macros (not sure I'd 
agree that AST macro is the right description), but because I write a 
lot of wrapping functions which are like "parameter modifiers". iopipe 
is full of them for instance.

Being able to inject a few statement before/after a call without having 
to dispatch to a separate function first is very useful for a wrapper. 
It's what the optimizer should do anyway, but making it part of the API 
makes a declaration that the function is a wrapper and should be treated 
that way.

Unfortunately, D does not implement this feature in a way that I prefer: 
https://issues.dlang.org/show_bug.cgi?id=15671

-Steve