[Issue 586] New: Cannot index tuple with non-type elements

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=586

           Summary: Cannot index tuple with non-type elements
           Product: D
           Version: 0.174
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: kirklin.mcdonald at gmail.com


Take the following code:

template Tu(T ...) {
    alias T[1] Tu; // Line 2
}

void foo() { }

void main() {
    alias Tu!(real, int) T; // Works, no problem.
    alias Tu!(4, int) U;    // Results in error.
    alias Tu!(foo, int) V;  // Results in error.
    alias Tu!("a", int) W;  // Results in error.
}

The error in all three cases is:

test.d(2): tuple T is used as a type
test.d(X): template instance test.Tu!(<whatever>, int) error instantiating

Any tuple containing elements which are not types cannot be indexed. This
limits certain kinds of advanced template code.

Bug 533 is a consequence of this bug. Bug 582 is essentially the same bug, but
refers to slicing tuples rather than indexing them.


--