KOS_OP_MATCH_SAME

• Style: EXTRA (LABEL, RAW, RAW): label, mark depth, slot index.

• Stack: [..., e] -> [..., e]; jump to a0 on a miss, e left either way.

• Semantics: e must equal the value in slot a2 of the mark at depth a1, both read through Datum: the same object, or equal under ==. An empty slot is a miss, and so is a DatumFrame on either side.

• Compiler form: Emitted by the match compiler for a back-reference (SAME) to a name a scope of the pattern captures. A back-reference whose name no enclosing scope binds always misses.