[tqchen]

Relax and TIRx dependent type fields need symbolic integer variables to be declared in a function signature without persisting parser-only metadata in IR.

• Accept standard module-level TypeVar declarations on Python 3.10+ and bare or int-bound PEP 695 parameters on Python 3.12+.
• Treat declarations as syntax sugar for fresh int64 TIR variables used by dependent signature fields; unused declarations disappear and no function attrs, type-parameter fields, or runtime parameters are added.
• Parse both versioned forms through shared signature plumbing while retaining dialect-specific annotation and body handling.

Representative TIRx Python 3.12+ output uses PEP 695 and postponed annotations, so dependent expressions are unquoted:

from __future__ import annotations

@T.prim_func(private=True)
def main[M](A: T.Buffer((M, M * T.int64(2)), "float32")):
    A[0, 0] = T.float32(1.0)

Before Python 3.12, the portable TIRx output uses a module-level TypeVar and quotes compound dependent expressions:

M = TypeVar("M")
@T.prim_func(private=True)
def main(A: T.Buffer((M, "M * T.int64(2)"), "float32")):
    A[0, 0] = T.float32(1.0)

The same declaration and printing rules apply to Relax tensor signatures.

Validation:

• Latest-main native build completed successfully.
• Consolidated Relax and TIRx TypeVar round-trip tests passed.
• Related Relax/TIRx parser, printer, and well-formedness suites passed 661 tests with 4 expected failures.
• Touched-file pre-commit hooks and diff checks passed.
• The implementation does not change Relax well-formedness analysis.