Inline expansion loses early-return semantics when branch conditions are non-exhaustive

[adust09]

Summary

leanMultisig/TODO.md

Line 87 in 43205ce

### Non exhaustive conditions in inlined functions

What I’ve tried

• Active flag approach: Introduced a guard variable that gets set to 0 after a return, expecting later statements to be skipped. This failed because the VM forbids overwriting the same memory slot (SSA), so the guard cannot be toggled from 1 to 0.
• Jump/Label approach: Replaced each inlined return with jump end_label. Although this preserves control flow in theory, we still assign directly into the caller’s result variable on every return path; the SSA invariant breaks when different paths try to write different values,
  and runtime fails with Computation invalid.