[Cocci] Error predicate determination with SmPL?

[elfring@users.sourceforge.net (SF Markus Elfring)]

> The semantic patch language can also be used to find
> specific return statements in the source files.
> How can this software help to find all of them
> within a function implementation?
> 
> How are the chances to improve static source code analysis
> possibilities for such a purpose?

A simple SmPL filter approach like the following works
already as expected to some degree.

@returns@
expression express;
identifier work;
type return_type;
@@
 return_type work(...)
 {
  ... when any
- return express;
  ... when any
 }


elfring at Sonne:~/Projekte/Coccinelle/Probe> spatch.opt -sp-file show_returns1.cocci API-test1.c
init_defs_builtins: /usr/local/lib/coccinelle/standard.h
HANDLING: API-test1.c
diff = 
--- API-test1.c
+++ /tmp/cocci-output-6241-92ed9e-API-test1.c
@@ -2,10 +2,8 @@
 
 int my_status(void)
 {
-  return 1;
 }
 
 int main(void)
 {
-  return my_status();
 }


I see further software development challenges here.

1. Do I need to specify a SmPL constraint like "non-void"
   for such a script?

2. The expression which is used for a specific return statement
   can be assigned to a SmPL metavariable in an other script variant.
   I would appreciate if I could process the extracted data
   in a more structured way somehow.

Regards,
Markus