www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 4137] New: Undefined identifier error in is(typeof())

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4137

           Summary: Undefined identifier error in is(typeof())
           Product: D
           Version: unspecified
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Keywords: diagnostic
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc


--- Comment #0 from bearophile_hugs eml.cc 2010-05-01 05:38:35 PDT ---
I don't know if there are ways to solve this problem, I hope this isn't another
situation like bug 3950.

This is wrong D2 code. The template Foo has the type parameter T while inside
it uses the parameter R:


template Foo(T) {
    enum bool Foo = is(typeof(R.length));
}
void main() {
    assert(Foo!(int[]));
}


The program compiles with no errors with dmd 2.043 and at run time produces:
core.exception.AssertError test2(5): Assertion failure

But to help debugging, I'd like the compiler to point R as a undefined
identifier (even with the 'did you mean...') at compile-time. Is this possible?

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
May 01 2010
parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4137


Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |INVALID


--- Comment #1 from Walter Bright <bugzilla digitalmars.com> 2010-05-01
09:45:29 PDT ---
This is expected & documented behavior. Compilation failures inside "is"
expressions cause the is expression result to be false. A lot of template code
relies on this.

If you want an error on R being undefined, use it somewhere else in addition to
inside the "is" expression.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
May 01 2010