KOS_OP_MATCH_TYPE_VAR / KOS_OP_MATCH_TYPE_FAST

• Style: EXTRA (LABEL, VAR) on MATCH_TYPE_VAR, (LABEL, FASTVAR) on MATCH_TYPE_FAST: label, type.

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

• Semantics: e read through Datum must be an instance of the type in the variable a1, read by name on the _VAR form and by fast index on the _FAST form.

• Compiler form: Emitted by the match compiler for a type test and for the instance check of a class pattern with no positional fields; the _VAR form pre-compile, the _FAST twin once convert_fast has lowered the variable.