prefer-method/remove-method/remove-all-methods/get-method/methods become
overlay macros over ctx-capturing *-setup fns (a multimethod's method table
lives on its VAR, so the name passes quoted — the defmulti/defmethod shape).
instance? likewise (class names don't evaluate to values); satisfies? is a
plain ctx-capturing fn (evaluated args). locking and defonce become overlay
macros — locking now also evaluates the monitor expr (the old arm skipped it
and any body form past the first); defonce keeps the existing-root check.
read-string and macroexpand-1 are ctx-capturing fns.
Removed all eleven from the evaluator special arms + special-symbol?,
host_iface special-names, and compiler uncompilable-heads. evaluator-test's
locking/instance? cases use init now (overlay macros need the full env).
Surfaced pre-existing (filed): multimethod dispatch records prefer-method
preferences on the var but never consults them in ambiguous isa dispatch.
Gate: conformance 296x3 (+11 tier-6c cases), fallback-zero 73/3, fixpoint,
self-host, sci, staged, suite 4049>=4034, all specs+unit.
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