Cstage's check.c:981-1006/1052-1082 builds a real (*T|nomem) /
([]T|nomem) return type for the alloc builtin; wwstage was returning
nil from exprtype's N_CALL arm (alloc is SK_FN with decl=nil under
seedprimitives), and checkletassign early-returned on nil src,
silently accepting `let p: *T = alloc(v);` without `!`. Stage
asymmetry that #30 papered over until now.
Three coordinated edits in check.ww:
- exprtype N_CALL: synthesize N_TTAGGED{N_TPTR{argt}, nomem} or
{N_TSLICE{u8}, nomem} for bare alloc (same-module gated, mirrors
cstage check.c:981-985 / task #23).
- exprtype N_TRYUNW: project the success variant so `let p:*T =
alloc(v)!;` resolves rhs to *T.
- isassignable: tagged → non-tagged is unconditionally not
assignable, forcing match/?/!.
950_selfcheck.c rows pin both ptr and slice forms.
Hojun-Cho
6f10c832a4