[Bug c++/12063] New: Enclosing temporary object constructors in parenthesis confuses compiler

[tal_arie at yahoo dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12063

           Summary: Enclosing temporary object constructors in parenthesis
                    confuses compiler
           Product: gcc
           Version: 3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tal_arie at yahoo dot com
                CC: gcc-bugs at gcc dot gnu dot org

There seems to be a problem compiling calls to constructors of temporary objects, when these 
constructors are surrounded by parenthesis, as the test case below shows: 
 
----- t.C 
class A { 
public: 
A& operator=(const A& _a) { return *this; } 
}; 
class B { 
  A& _a ; 
public: 
   B(const A& a) : _a((A&)a) {} 
} ; 
 
 
void foo(const B& b) { 
} 
void bar() { 
foo( B(A()) ) ; // this works 
foo( B((A()) ) ; / this does not compile 
A a; 
foo( B( (a=A())) ) ; // this compiles 
} 
 
------- 
Compiling: 
g++ -c t.C 
Result: 
t.C: In function `void bar()': 
t.C:17: error: parse error before `)' token 
t.C:19: error: `a' undeclared (first use this function) 
t.C:19: error: (Each undeclared identifier is reported only once for each 
   function it appears in.) 
 
If I comment out line 17 (where the comments say it does not compile) I get a clean compile. 
---------- 
 
As for the need to surround constructors with parenthesis, I'm creating objects using overloaded 
operators, and use parenthesis to override the default operator precedence, only that with g++ it 
does not seem to work (it does work with another compiler that I have tried).