https://issues.dlang.org/show_bug.cgi?id=13658

          Issue ID: 13658
           Summary: Array length type is not size_t
           Product: D
           Version: D2
          Hardware: All
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: markisaa@umich.edu

According to the language reference at: http://dlang.org/arrays, the .length property of an array is meant to return a value with type size_t. That is not the case on Windows with dmd 2.066.

This issue is more widespread than just the .length property; I discovered this by trying to index an array with a ulong (same type as size_t) and found dmd yelling about implicit conversions to uint. The problematic code was of the form:

myArray[thingThatReturnsULong() - 1 - 1];

For reference, the precise line of code that breaks: https://github.com/facebook/flint/blob/master/Checks.d#L3016

I confirmed the types of size_t, myArray.length, and a few other things using
pragma(msg, typeof(thing));



For what it's worth, if you pointed me at roughly the write part of the code that needed fixing, I would gladly make the change; I wasn't able to find the relevant code in druntime and the dmd repo is a mystery to me.

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