My favourite game: DMD guess the error reason.

[Iain Buclaw via Digitalmars-d]

Here's a small puzzle, in which there are both a simple and 
cryptic combined. To make it easier, I've added a some multiple 
choice answers at the bottom.

Winner of the simple puzzle gets a free beer from me at dconf.
Winner of the cryptic puzzle gets a free meal.


Q: What is the explanation for this error when building 
std.bigint?
---
$ aarch64-linux-gnu-gdc -o std/bigint.o -Wall -Werror -g 
-frelease -O2 -nostdinc -pipe -Wno-deprecated -c std/bigint.d

std/uni.d:2627:50: error: template 
std.algorithm.searching.countUntil cannot deduce function from 
argument types !("a[0] > 0x80")(CodepointInterval[]), candidates 
are:
std/algorithm/searching.d:684:11: note: 
std.algorithm.searching.countUntil(alias pred = "a == b", R, 
Rs...)(R haystack, Rs needles) if (isForwardRange!R && Rs.length 
 > 0 && isForwardRange!(Rs[0]) == isInputRange!(Rs[0]) && 
is(typeof(startsWith!pred(haystack, needles[0]))) && (Rs.length 
== 1 || is(typeof(countUntil!pred(haystack, 
needles[1..__dollar])))))
std/algorithm/searching.d:772:11: note: 
std.algorithm.searching.countUntil(alias pred = "a == b", R, N)(R 
haystack, N needle) if (isInputRange!R && 
is(typeof(binaryFun!pred(haystack.front, needle)) : bool))
std/algorithm/searching.d:841:11: note: 
std.algorithm.searching.countUntil(alias pred, R)(R haystack) if 
(isInputRange!R && is(typeof(unaryFun!pred(haystack.front)) : 
bool))
std/uni.d:1853:29: error: template instance 
std.uni.InversionList!(GcPolicy) error instantiating
---

A:
---
[1]: Template deduction/matching failed to find a suitable 
candidate for countUntil.
[2]: The ptrdiff_t and size_t types have a different size.
[3]: An untested version path had a semantic error.
[4]: An untested template instantiation had a missing member.
[5]: The template function core.varargs.va_arg does not exist.
[6]: A static assert was triggered in std.math.
[7]: The std.format module does not support 128-bit reals.
[8]: The compiler didn't add a predefined version for little/big 
endian.
[9]: The order that modules are imported on AArch64 unearthed a 
bug in the semantic pass.
---


Iain.