https://issues.dlang.org/show_bug.cgi?id=13479

          Issue ID: 13479
           Summary: Templates not emitted when instantiated in mixins
                    mixed in functions
           Product: D
           Version: D2
          Hardware: All
                OS: Windows
            Status: NEW
          Keywords: link-failure
          Severity: regression
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: thecybershadow@gmail.com

///// test.d /////
mixin template F()
{
    void t()()
    {
    }

    alias t!() a;
}

void main()
{
    mixin F!();
    a();
}
//////////////////

Linker complains:
Symbol Undefined _D4test4mainFZ8__mixin16__T1tZ1tMFNaNbNiNfZv

Introduced in https://github.com/D-Programming-Language/dmd/pull/3948.

Possibly related to issue 13478?

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