[bug #45191] Implicit argument forwarding limited by infinite recursion checker

[Julio Guerra]

URL:
  <http://savannah.gnu.org/bugs/?45191>

                 Summary: Implicit argument forwarding limited by infinite
recursion checker
                 Project: make
            Submitted by: julio
            Submitted on: Tue 26 May 2015 10:46:34 AM GMT
                Severity: 3 - Normal
              Item Group: Enhancement
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
       Component Version: 4.0
        Operating System: POSIX-Based
           Fixed Release: None
           Triage Status: None

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Details:

Hi,

It seems the infinite recursion detector does not consider implicit argument
forwarding possible. When recursively expanding a variable without using
`call`, it is assumed it does not use $1, $2, etc. and is thus considered as
an infinite recursion.

```
list  = $(list_) # list_ called in the context of list, $1 of `list_` is the
$1 of `list`
list_ = $($1) # dummy example
a     = $(call list,b) # new "call scope" #2 with $1 = b
b     = ok
$(error $(call list,a)) # new "call scope" #1 with $1 = a
```
Result: *** Recursive variable 'list_' references itself (eventually).

The expansion is simple:
list(a)
list_(a)
$a
list(b)
list_(b) <- error detected
ok

The error disappears when forwarding arguments explicitly:
```
list  = $(call list_,$1)
list_ = $($1)
a     = $(call list,b)
b     = ok
$(error $(call list,a))
```
Result: ok

Implicit forwarding is very useful in some cases (e.g `arg1 = $(strip $1)`),
it would be nice to officially handle it.

Regards,




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