[Issue 24567] New: In interpolation token strings: "$(expression)" is not treated as interpolation expression

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24567

          Issue ID: 24567
           Summary: In interpolation token strings: "$(expression)" is not
                    treated as interpolation expression
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: weltensturm at gmail.com

The following is supposed to fill the members of `test` with the content of
`assocarray`:


import std;

void main(){

    struct Test {
        int a;
    }
    Test test;
    auto assocarray = [
        "a": 1
    ];

    static foreach(member; __traits(allMembers, Test)) {
        mixin(iq{
            writeln("$(member)");
            test.$(member) = assocarray.get("$(member)", -1);
        }.text);
    }

    writeln(test.a);
    assert(test.a == 1);

}


Output:

$(member)
-1
core.exception.AssertError at .\test_token_interpolation.d(22): Assertion failure


It looks like token strings are "tokenized" before interpolation and not after,
which results in "string" tokens being completely ignored for interpolation.

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