[Issue 14720] New: Template function reported non-template

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14720

          Issue ID: 14720
           Summary: Template function reported non-template
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: yshuiv7 at gmail.com

I'm not sure if this is a bug or just really confusing error messages:

This piece of code:

import std.traits;
template ReturnTypeEx(alias A, B) {
    alias ReturnTypeEx = ReturnType!(A!B);
}
template a(R) {
    void a(S)(auto ref S i) { }
}
template b(alias R) {
    void b(S)(S i) {
        alias Ra = ReturnTypeEx!(R, S);
    }
}
void main() {
    alias bb = b!(a!ulong);
    alias bbb =  ReturnTypeEx!(bb, int);
}

Generate error saying the nested template function a.a is not a template
function.

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