https://issues.dlang.org/show_bug.cgi?id=12961

          Issue ID: 12961
           Summary: Removing private import for std.conv from std.traits
                    causes dmd test suite failure
           Product: D
           Version: unspecified
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: jmdavisProg@gmx.com

In https://github.com/D-Programming-Language/phobos/pull/2260 I'm removing the deprecated

alias unsigned = std.conv.unsigned;

from std.traits, and that works fine. However, if I remove the import for std.conv (which was there just to enable that alias), then the dmd test suit fails

../src/dmd -m64 -Irunnable   -odtest_results/runnable -oftest_results/runnable/testaa2_0 runnable/testaa2.d runnable/testaa2.d(242): Error: associative array key type S does not have 'const int opCmp(ref const S)' member function

The are no imports for std.conv or std.traits in that file. The only module-level import is std.math. std.math _does_ import std.traits, but it does so privately. Adding an import to std.conv in test3825x (the failing test) makes it so that it passes again (in spite of the fact that it isn't using anything from std.conv).

I'm going to leave the import for std.conv in std.traits for the moment, since I have no idea what other impacts removing it will have, but there's definitely something bizarre going on here. Removing the import for std.conv from std.traits should have no impact on anything outside of std.traits.

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