Spreading a falsy primitive copies nothing, so `...(cond && { k: v })` is
the optional-field idiom `...(cond ? { k: v } : {})`. The `&&` spelling
(the @edge-runtime/cookies parseSetCookie shape) was refused with a record
shape mismatch (SC2002).
When the spread's type mixes the record with primitive arms, the literal
lowering now uses the existing conditional-spread desugar: cond evaluates
once, v only when taken, and the absent arm leaves the optional field
undefined. Record and record-or-unit spreads keep the source-copy path.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
