[Issue 15110] New: pragma(inline) rarely works how I want it to

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15110

          Issue ID: 15110
           Summary: pragma(inline) rarely works how I want it to
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: turkeyman at gmail.com

pragma(inline, true)
R normalisedSubtract(T, U, R = ResultType!(T, U))(T a, U b)
{
    R x = cast(R)a;//convertNormInt!R(a);
    R y = cast(R)b;//convertNormInt!R(b);
    static if(isUnsigned!R)
    {
        if(x <= y)
            return 0;
        return cast(R)(x - y);
    }
    else
    {
        auto r = x - y;
        if(r < R.min)
            r = R.min;
        else static if(isSigned!R)
        {
            if(r > R.max)
                r = R.max;
        }
        return cast(R)r;
    }
}


src\std\experimental\color\internal\normint.d(90): Error: function
std.experimental.color.internal.normint.normalisedSubtract!(ubyte, ubyte,
ubyte).normalisedSubtract cannot inline function


This function is literally nothing more than a single integer subtract.
I have no idea why this won't inline. I experience this general problem quite a
bit.
Strangely, the addition compliment to this function doesn't complain.

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