issue with each specifically for x86

[Ali Çehreli]

On 03/07/2018 10:57 AM, Matt Gamble wrote:
> This is a record for me with two 32bit vs 64bit issues in one day. Seems 
> to be a problem with using "each" under 32bit which can be fixed by 
> using foreach or switching to x64. Am I doing something wrong or is this 
> the second bug I've found today?
> 
> Below is a silly case, that replicates an error. (i.e. I know I could 
> use iota(0,9,2).array), but that does not demonstrate the potential bug 
> and would not fix my actual program.)
> 
> import std.range;
> import std.algorithm;
> import std.stdio;
> 
> unittest
> {
>      auto a = new double[9];
>      a[0] = 0;
>      iota(1,a.length).each!(i => a[i] = a[i-1] + 2);
>      writeln(a);
> }
> 
> //x86, wrong, error
> //[-nan, 2, 4, 6, 8, 10, 12, 14, 16]
> //First-chance exception: std.format.FormatException Unterminated format 
> specifier: "%" at C:\D\dmd2\windows\bin\..\..\src\phobos\std\format.d(1175)
> 
> //x64, correct
> //[0, 2, 4, 6, 8, 10, 12, 14, 16]
> 
> unittest
> {
>      auto a = new double[9];
>      a[0] = 0;
>      foreach(i; 1..a.length) a[i] = a[i - 1] + 2;
>      writeln(a);
> }
> 
> //x86, correct
> //[0, 2, 4, 6, 8, 10, 12, 14, 16]
> 
> //x64, correct
> //[0, 2, 4, 6, 8, 10, 12, 14, 16]
> 
> This is windows 10, DMD v2.076.1
> 

Confirmed on Linux with dmd 2.078.1

It's somehow related to the unused return value of the lambda. The 
following code has the same error:

     iota(1,a.length).each!((i) {
             a[i] = a[i-1] + 2;
             return a[i];
         });

The error disappears when that return statement is commented-out.

Please file a dmd bug after making sure that 2.079 still has it. (Too 
lazy to install right now.)

An ldc that I have handy does not have this bug:

   based on DMD v2.073.2 and LLVM 4.0.0

Ali