Bug 525 – can't use array variable in typetuple index

import std.typetuple; const int[] test=[1]; alias TypeTuple!(ulong,uint,ushort,ubyte) tuple; static assert(is(tuple[1]==uint));//ok static assert(is(tuple[test[0]]==uint));//failed Output: tuple_bug.d(5): static assert (is((ulong, uint, ushort, ubyte)[void[0]] == uint)) is false

[email protected] wrote: > http://d.puremagic.com/issues/show_bug.cgi?id=525 > > Summary: can't use array variable in tuple index > Product: D > Version: unspecified > Platform: All > OS/Version: All > Status: NEW > Severity: normal > Priority: P2 > Component: DMD > AssignedTo: [email protected] > ReportedBy: [email protected] > > > import std.typetuple; > const int[] test=[1]; > alias TypeTuple!(ulong,uint,ushort,ubyte) tuple; > static assert(is(tuple[1]==uint));//ok > static assert(is(tuple[test[0]]==uint));//failed > > Output: > tuple_bug.d(5): static assert (is((ulong, uint, ushort, ubyte)[void[0]] == > uint)) is false > > This is because there's no constant folding of array indexes and slices. A simpler example: --------- const int a[] = [1,2,3]; const int b = a[2]; --------- Error: non-constant expression (a)[2]

I dont think so. I update example. import std.typetuple; const char[] a="\x01"; const char b=a[0];//ok const char[] c="test"; static assert(c[a[0]]=='e');//ok alias TypeTuple!(ulong,uint,ushort,ubyte) tuple; static assert(is(tuple[1]==uint));//ok static assert(is(tuple[a[0]]==uint));//failed

[email protected] wrote: > http://d.puremagic.com/issues/show_bug.cgi?id=525 > > > > > > ------- Comment #2 from [email protected] 2006-11-16 17:40 ------- > I dont think so. I update example. > > import std.typetuple; > const char[] a="\x01"; > const char b=a[0];//ok > const char[] c="test"; > static assert(c[a[0]]=='e');//ok > alias TypeTuple!(ulong,uint,ushort,ubyte) tuple; > static assert(is(tuple[1]==uint));//ok > static assert(is(tuple[a[0]]==uint));//failed Interesting. Does it work with static assert(is(tuple[b]==uint)); ?

it does.

Fixed DMD 0.175