[Issue 23360] New: Template alias to tuple member variable doesn't expand

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23360

          Issue ID: 23360
           Summary: Template alias to tuple member variable doesn't expand
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: snarwin+bugzilla at gmail.com

As of DMD 2.100.2, the following program fails to compile:

---
alias AliasSeq(Args...) = Args;

struct Foo {    
    AliasSeq!(int) tuple;    
    alias slice() = tuple;    
}

void main() {    
    Foo foo;
    AliasSeq!(int) t = foo.slice!();
}
---

The error message is:

---
bug.d(10): Error: cannot implicitly convert expression
`foo.tuple(__tuple_field_0)` of type `(int)` to `int`
---

In other words, the tuple expression on the right-hand side is not expanded,
which causes a type mismatch.

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