I'm getting an ICE on Visual Studio 2015 CTP 6. Unfortunately, this is happening in a large project, and I can't post the whole code here, and I have been unable to reproduce the problem on a minimal sample. What I'm hoping to get is help in constructing such a sample (to submit to Microsoft) or possibly illumination regarding what's happening and/or what I'm doing wrong.
This is a mock-up of what I'm doing. (Note that the code I'm presenting here does NOT generate an ICE; I'm merely using this simple example to explain the situation.)
I have a class A which is not copyable (it has a couple of "reference" members) and doesn't have a default constructor. Another class, B holds an array of As (plain C array of A values, no references/pointers) and I'm initializing this array in the constructor of B using uniform initialization syntax. See the sample code below.
struct B;
struct A
{
int & x;
B * b;
A (B * b_, int & x_) : x (x_), b (b_) {}
A (A const &) = delete;
A & operator = (A const &) = delete;
};
struct B
{
A a [3];
int foo;
B ()
: a {{this,foo},{this,foo},{nullptr,foo}} // <-- THE CULPRIT!
, foo (2)
{ // <-- This is where the compiler says the error occurs
}
};
int main ()
{
B b;
return 0;
}
I can't use std::array because I need to construct the elements in their final place (can't copy.) I can't use std::vector because I need B to contain the As.
Note that if I don't use an array and use individual variables (e.g. A a0, a1, a2;, which I can do because the array is small and fixed in size) the ICE goes away. But this is not what I want since I'll lose ability to get to them by index, which I need. I can use a union of the loose variables over the array to solve my ICE problem and get indexing (construct using the variables, access using the array,) but I think that would result in "undefined behavior" and seems convoluted.
The obvious differences between the above sample and my actual code (aside from the scale) is that A and B are classes instead of structs, each is declared/defined in its own source/header file pair, and none of the constructors is inline. (I duplicated these and still couldn't reproduce the ICE.)
For my actual project, I've tried cleaning the built files and rebuild, to no avail. Any suggestions, etc.?
P.S. I'm not sure if my title is suitable. Any suggestions on that?!?!
UPDATE 1: This is the compiler file referenced in the C1001 fatal error message: (compiler file 'f:\dd\vctools\compiler\utc\src\p2\main.c', line 230).
UPDATE 2: Since I had forgotten to mention, the codebase compiles cleanly (and correctly) under GCC 4.9.2 in C++14 mode.
Also, I'm compiling with all optimizations disabled.
UPDATE 3: I have found out that if I rearrange the member data in B and put the array at the very end, the code compiles. I've tried several other permutations and it sometimes does compile and sometimes doesn't. I can't see any patterns regarding what other members coming before the array make the compiler go full ICE! (being UDTs or primitives, having constructors or not, POD or not, reference or pointer or value type, ...)
This means that I have sort of a solution for my problem, although my internal class layout is important to me and this application, I can tolerate the performance hit (due to cache misses resulting from putting some hot data apart from the rest) in order to get past this thing.
However, I still really like a minimal repro of the ICE to be able to submit to Microsoft. I don't want to be stuck with this for the next two years (at least!)
UPDATE 4: I have tried VS2015 RC and the ICE is still there (although the error message refers to a different internal line of code, line 247 in the same "main.c" file.)
And I have opened a bug report on Microsoft Connect.
I did report this to Microsoft, and after sharing some of my project code with them, it seems that the problem has been tracked down and fixed. They said that the fix will be included in the final VC14 release.
Thanks for the comments and pointers.