https://issues.dlang.org/show_bug.cgi?id=13619

          Issue ID: 13619
           Summary: std.container.array capacity not updated when length
                    increases
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: trivial
          Priority: P1
         Component: Phobos
          Assignee: nobody@puremagic.com
          Reporter: dlang@thedeemon.com

import std.container;

void main() {
  Array!int a; // empty Array
  a.length = 10;
  // now payload is allocated, length is set to 10, but capacity is still 0!

  // try to append a value
  a ~= 1; // runtime error (assertion: capacity < length !)
}

Fix is trivial, Array.Payload.length setter must update _capacity field when it reallocates data.

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