Exported generator returns wrong values under -shared: __decls prints the boxed generator object as a value tuple #314

Problem

A generator exported from a shared library returns garbage when called from a program compiled against that library with -shared:

// export_gendecl.ts
export function* gd() { yield 1; yield 2; }

// import_gendecl.ts
import './export_gendecl'
function main() {
    let sum = 0;
    for (const v of gd()) sum += v;
    assert(sum == 3, "gendecl");
    print("done.");
}

export const gd = function* () { yield 1; yield 2; }; fails the same way.

Observed (release build, Windows)

Cause

The declaration text embedded in the library (__decls) prints the generator's return type as a plain value tuple:

@dllimport
let gen : () => {.step:s32, next(): {value:s32, done:boolean}};

The importer reads that back as !ts.tuple<{"step",si32},{"next",...}>, a value. The library's generator wrapper returns a boxed object (!ts.object<!ts.tuple<...>>, see the generator object-wrapper change in #245). The two sides disagree on the return value's layout.

The printed field name also keeps the internal .step dot.

Notes

• Found while working on Exported const arrow function is unresolved across modules (undefined symbol / JIT crash) #311 (branch fix-const-function-values). It is not caused by that work: the older debug build fails the same export function* case.
• Likely fix area: MLIRDeclarationPrinter, printing an ObjectType wrapping a tuple as a reference type that reads back boxed. The static and JIT paths don't go through __decls, which is why they pass.

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