An expression-bodied lambda `f :: (x: s32) => x * 2;` without an explicit
return type reaches emit_llvm declareFunction with func.ret = .unresolved and
trips the emission guard panic. Explicit `-> s32` works; the same lambda inside
a large module (the old 50-smoke.sx) resolves fine — so inferred-return
resolution for => lambdas runs only conditionally. Repro co-located.
Surfaced while splitting 50-smoke.sx (test-layout migration); the functions
section uses this exact construct, so the split is paused per the impassable
rule (no workaround).
70b4341682