Codegen targets

Faber has one language and many compilation contracts. Not every feature must lower to every target. This page documents which features each target supports, erases, warns on, or rejects.

Policy verbs

Verb	Meaning
Support	Lowers with intended semantics
Erase	Typechecks; codegen drops target-specific semantics
Warn	Legal Faber; no effect or degraded behaviour on target
Reject	Check or emit fails with explicit diagnostic
Defer	Parses/binds; lowering not implemented for any target
Limited	Stable contract with explicit subset gates

Target table

Target	Lane	Build	Run	Package	Policy
`rust`	HIR	yes	yes	yes	Support
`fmir-text`	MIR	yes	yes	yes	Support
`fmir`	MIR	yes	yes	yes	Support
`fmir-bin`	MIR	yes	yes	yes	Support
`faber`	HIR	yes	no	no	Support
`ts`	HIR	yes	no	no	Probe
`go`	HIR	yes	no	no	Erase
`wasm`	MIR	yes	no	no	Limited
`wasm-text`	MIR	yes	no	no	Limited
`llvm-text`	MIR	yes	no	no	Limited
`metal-text`	MIR	yes	no	no	Limited
`wgsl-text`	MIR	yes	no	no	Limited
`sexp`	MIR	yes	no	no	Limited

Pipeline routing

Source → Lex → Parse → Collect → Resolve → Lower → Typecheck → Analysis
                                                              ↓
                                    ┌─────────────────────────┴──────────┐
                                    │                                    │
                              HIR backends                        MIR backends
                                    │                                    │
            Rust · Faber · TS · Go            fmir · wasm · llvm · metal · wgsl · sexp

Application lane (HIR)

Target	Measured floor
Rust	Production path. Borrow modes, CLI generation, failable Result lowering.
Faber	Canonical source view / round-trip. Not an execution backend.
TypeScript	288/318 analysed · 268/318 typecheck-valid · 262/318 runnable
Go	146/216 pass. Borrow modes erased; `ad` rejected.

Systems lane (MIR)

Target	Measured floor
fmir*	Package MIR images; runner proves source independence.
wasm	200/289 emitted · 195/289 validate · 171/289 stub-host runnable
llvm-text	249/289 emitted · 232/289 verifier-valid · 65/289 runnable
metal-text	Device-safe kernel subset; 88 focused tests. Campaign paused.
wgsl-text	Validates with naga 30.x. 87 focused tests. Reflection sidecar.
sexp	193 emitted · 190 Racket-compiled · 190 Racket-run. Validation target.

For live capability flags, run faber targets.