Three adjacent cells of the shared count surface still diverged from the
rest; all now route through the same leaf+fold+narrow+diagnose path.
1. Aliased integer constraint bypassed the value-param range gate — only
builtin constraint names matched intTypeRange, so Box(5_000_000_000)
with `$K: Count` (Count :: u32) compiled and bound a truncated value.
resolveValueParamArg (shared by both the struct AND type-fn binder) now
resolves the constraint to its underlying builtin via
canonicalIntConstraintName (Count -> u32, Small -> s8) before
range-checking, so an aliased integer constraint behaves exactly like
the builtin it names.
2. A named const with an expression RHS (M :: 2; N :: M + 1) did not fold
as a count — moduleConstInt read only a literal RHS node. It now folds
every const's RHS through the shared evalConstIntExpr, cycle-guarded
(mutual / self cycles fold to null, not a stack overflow), and pass-0
pre-registers expression-RHS consts. N :: M + 1 == 3 at every consumer:
dim (direct + alias), Vector lane, value-param (struct + type-fn),
inline for.
3. Stateful resolveArrayLen still fabricated length 0 after a failed fold;
it now returns null -> the .unresolved sentinel (no fabrication). The
binding's lowering never reaches sizeOf (alloca defers it; hasErrors
aborts first) and a field access on an already-diagnosed .unresolved
value is poison-suppressed (emitFieldError), so a failed-fold dim emits
ONE clean diagnostic with no panic.
Regressions: examples/0146 (full positive matrix — every consumer x leaf
form), 1135 (aliased u32 + s8 overflow), 1136 (direct non-const dim halts
cleanly). The cascade cleanup also tightened 1502/1503 to one diagnostic.
Unit test added for moduleConstInt expression-folding + cycle detection.
Two remaining siblings in F0.4's comptime-int path.
1. Type-returning function with a value param used as a TYPE annotation
(`b : Make(N, s64)` where `Make :: ($K: u32, $T: Type) -> Type`):
- `isValueParamPosition` (semantic_diagnostics) now also skips a value
param of a `fn_ast_map` type-returning function, so `N` is not walked
as the type name "N" ("unknown type 'N'").
- `resolveParameterizedWithBindings` routes a type-returning-function
name to `instantiateTypeFunction` (the `.call` path already did).
- `instantiateTypeFunction` resolves a general return-type expression
(`return [K]T`) with bindings active — not just struct/union returns.
`Make(N, s64)`, `Make(M + 1, s64)`, `Make(3, s64)` all resolve to one
`[3]s64`.
2. Oversized dim/lane fold panicked the compiler (0087): an array dim /
Vector lane folded to a valid i64 (5e9) then narrowed to u32 with an
unchecked `@intCast`. New single gate `program_index.foldDimU32` folds
via `evalConstIntExpr` then range-checks `[min, maxInt(u32)]`; the three
narrowing sites (resolveArrayLen stateful + stateless, resolveVectorLane)
all route through it and emit a clean diagnostic + halt instead of
panicking. Value-param args stay i64 until used as a dim/lane, where the
same gate checks them.
Regressions: examples/0208 (value-param type function), examples/1130
(oversized array dim clean halt), examples/1503 (oversized Vector lane
clean halt). Marks issue 0087 RESOLVED.
Gate: zig build, zig build test, bash tests/run_examples.sh — 398 passed,
0 failed, 0 timed out.
