[Issue 20717] New: Unsilenced bogus "undefined identifier" error from speculative collision

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20717

          Issue ID: 20717
           Summary: Unsilenced bogus "undefined identifier" error from
                    speculative collision
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: regression
          Priority: P3
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: dlang-bugzilla at thecybershadow.net

//////// test.d ////////
pragma(msg, is(typeof({
    struct S {
        struct Foo {}
        struct Bar() {}
        alias Bar = Foo;
    }
})));
////////////////////////

Compiler output:
test.d(5): Error: undefined identifier `Foo`
false

Introduced in https://github.com/dlang/dmd/pull/10078

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