https://issues.dlang.org/show_bug.cgi?id=9792

Nathan S. <n8sh.secondary@hotmail.com> changed:

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                 CC|                            |n8sh.secondary@hotmail.com
           See Also|                            |https://issues.dlang.org/sh
                   |                            |ow_bug.cgi?id=7521

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https://issues.dlang.org/show_bug.cgi?id=9792

Ali Cehreli <acehreli@yahoo.com> changed:

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                 CC|                            |acehreli@yahoo.com

--- Comment #3 from Ali Cehreli <acehreli@yahoo.com> ---
I ran into this in a post condition code:

import std.algorithm;

auto foo()
out (result; result.length == 1) { // <-- ERROR
  return [ 0 ].sort;
}

void main() {
}

Error: mutable method `std.range.SortedRange!(int[], "a <
b").SortedRange.length` is not callable using a `const` object
Consider adding `const` or `inout` to std.range.SortedRange!(int[], "a <
b").SortedRange.length

Ali

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https://issues.dlang.org/show_bug.cgi?id=9792

Witold Baryluk <witold.baryluk+d@gmail.com> changed:

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                 CC|                            |witold.baryluk+d@gmail.com

--- Comment #4 from Witold Baryluk <witold.baryluk+d@gmail.com> ---
I got similar issues with constness, in other cirumstances. `opIndex` and `opSlice` could be made const too, if they return const range or SortedRange, and underlying Range is const.

I have a method like this:

void search(Range, T)(in T[] needles, in SortedRange!(Range) haystack, long[]
ret, const long index_offset) {

it is called as search(needles, assumeSorted(kaystack), ret, 0);


but the body of this function does pose issues:

search.d:67:7: error: mutable method std.range.SortedRange!(const(int)[], "a <
b").SortedRange.length is not callable using a const object
   67 |   if (haystack.length == 0) {
      |       ^
search.d:83:17: error: mutable method std.range.SortedRange!(const(int)[], "a <
b").SortedRange.opIndex is not callable using a const object
   83 |     if (haystack[i] == needles[j]) {


This is with gdc 9.3.0-11 and libgphobos76 9.3.0-11.



It looks like automatic inference of const methods, or specialization of const and non-const (at the cost of repeating the same code twice) is required to make it work.

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https://issues.dlang.org/show_bug.cgi?id=9792

--- Comment #5 from Witold Baryluk <witold.baryluk+d@gmail.com> ---
Same issue with `SortedRange.trisect` too.

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https://issues.dlang.org/show_bug.cgi?id=9792

Iain Buclaw <ibuclaw@gdcproject.org> changed:

           What    |Removed                     |Added
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           Priority|P2                          |P3

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