Accept clamp() and env() wherever calc() is accepted

[davesnx]

clamp() and env() were fully implemented as grammar functions but no property could reach them: the shared Extended_length and Extended_percentage value types listed calc(), min() and max() as their math alternatives and nothing else, so width: clamp(10px, 5vw, 100px) and padding-top: env(safe-area-inset-top) were rejected with "invalid value". The Ahrefs monorepo works around it with an inline style. Both functions are now alternatives wherever calc() already is: clamp() on length, percentage, angle, time and frequency; env() on length and percentage, the only types it produces. Fixing this exposed a second defect: env()'s own grammar demanded a comma even without a fallback, so the common env(safe-area-inset-top) form failed; the grammar now reads env( <custom-ident> [ ',' <declaration-value> ]? ).

width: clamp(10px, 5vw, 100px)          -> .css-zpelvd{width:clamp(10px, 5vw, 100px);}
padding-top: env(safe-area-inset-top)   -> .css-2ju9ys{padding-top:env(safe-area-inset-top);}
width: calc(clamp(1px, 2vw, 3px) + 1px) -> .css-1vs0z9k{width:calc(clamp(1px, 2vw, 3px) + 1px);}

Evidence at e1c6df5:

• New cram test packages/ppx/test/css-support/clamp-env-functions.t: six declarations, all rejected before with the "Expected 'length', 'percentage', 'calc()', … 'min()'" message, all rendered after as passthrough text like calc().
• Types.ml gains the matching variant arms; the runtime witnesses are unchanged because these values render as text.
• make format-check, make build, make test: all exit 0.

Risk: two-way door. Only previously rejected values change behaviour; no existing output or hash changes.

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1 Skipped Deployment

Project	Deployment	Actions	Updated
styled-ppx	Ignored	Preview	Sep 23, 2026 6:40am UTC