[Issue 16465] Template alias does not get unwrapped in templated functions

via Digitalmars-d-bugs digitalmars-d-bugs at puremagic.com
Sun Sep 11 06:27:46 PDT 2016


https://issues.dlang.org/show_bug.cgi?id=16465

b2.temp at gmx.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Hardware|x86_64                      |All
                 OS|Windows                     |All

--- Comment #1 from b2.temp at gmx.com ---
1. I don't see the first function working.
(https://dpaste.dzfl.pl/2b462faf70b0). WHen you try to instantiate both gives
the same error.

2. If you don't do partial instantiation then your alias can be declared more
simply as 'alias TestAlias = TestType;'

3. The real problem you encounter here is that TestType template argument
cannot be deduced from the value passed to the constructor:

    struct TestType(T)
    {
        T data;
    }

    void main()
    {
        auto a = TestType(0); // same error
    }

This is exactly what happens when you call TestFunctionA.
For example you can replace the declaration by:

    void testFunctionB(T)(T arg) {}

and if you call

    testFunction(TestType(0));

you get exactly the same error.

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