wcc: array-init accept-if-fits coercion (#130, merges #146)

Align bare-int array-init assignability to Hare's literal-fits rule
(ref/harec/src/types.c promote_flexible): accept untyped-int array
elements that FIT the element type, reject out-of-range loud. cstage
(rejected all bare-int arrays, over-strict) and wwstage (accepted +
silently truncated out-of-range, over-loose) converge to the same
accept-if-fits rule. Per-element: foldable int literal range-checked
against element type [min,max] via def_cast_fits (rule-13 type-table
widths); non-foldable element falls back to type_assignable.

cstage: new arrlit_init_fits, N_LET decl-check fallback after whole-
array type_assignable fails. wwstage: checkletassign array branch +
route top-level lets through checkletassign (were unchecked — only
function-body lets ran assignability; closes #146 wwstage str->u8
over-accept).

Scalar-init range-check (let X:u8=300 truncates, both stages,
pre-existing) deferred to #148 — language-wide, needs bootstrap audit
+ explicit-cast conversion. def-array accept-if-fits deferred to #151
(def constfold machinery, different risk). Both bootstrap-NEUTRAL.

Test 920 (14 rows — accept: in-range u8/u32/u64/i32 + u8/i8 boundary +
typed regression + non-foldable-body; reject: over-range + over-256 +
i8-over + neg-for-unsigned + str->u8 + non-foldable-wider). Non-
foldable else-branch cs==ww verified (matching-type accept + byte-id;
wider-runtime-int reject both stages). Make test: 183/183 incl 990-997
byte-id + combined_ww_fresh.

selfhost/cmd/wwdump/main.combined.ww

@@ -10673,6 +10673,66 @@ fn checkletassign(c: *checker, n: *node) void = {
 			};
 		};
 	};
+	// #130: array-init accept-if-fits. When lhs is [N]T and rhs is an
+	// array literal, per-element check: foldable int literal →
+	// defcastfits range-check (reject out-of-range loud, rule-7/Drew —
+	// Hare range-checks at literal-value level); non-foldable →
+	// isassignable to the element type. This BOTH accepts in-range
+	// bare-int (the #130 headline, matching cstage) AND closes the
+	// wwstage over-accept where str→u8 / out-of-range silently passed
+	// (#146 merged). Mirrors cstage check.c arrlit_init_fits. Scoped
+	// to the array path; scalar-init range-check is a separate
+	// language-wide gap (#148).
+	if (n.lhs.kind == nkind.N_TARRAY) {
+		if (n.rhs.kind == nkind.N_ARRLIT) {
+			let elemtn: *node = n.lhs.lhs;
+			let at: *tinfo = tinfofornode(c, n.lhs);
+			let et: *tinfo = nil;
+			if (at != nil) { et = at.sub; };
+			for (et != nil && et.kind == tykind.TY_NAMED) { et = et.under; };
+			let e: *node = n.rhs.list;
+			for (e != nil) {
+				let skip: bool = false;
+				if (e.kind == nkind.N_FIELD) {
+					if (streq(e.str, "...")) { skip = true; };
+				};
+				if (!skip) {
+					let ev: *node = e;
+					for (ev != nil && ev.kind == nkind.N_CAST) { ev = ev.lhs; };
+					let v: u64 = 0u64;
+					let folded: bool = false;
+					if (et != nil) {
+						if (typeisint(et)) {
+							if (ev != nil) {
+								folded = foldintliteral(ev, &v);
+							};
+						};
+					};
+					if (folded) {
+						if (!defcastfits(et, v)) {
+							let m: str = "let: array element out of range\n";
+							os.write(2, m.ptr, m.len: u64);
+							c.errs += 1;
+							return;
+						};
+					} else {
+						let est: *node = exprtype(c, ev, elemtn);
+						let conf2: bool = false;
+						if (est != nil) {
+							if (!isassignable(c, elemtn, est, &conf2)) {
+								if (conf2) {
+									errnotassign(c, elemtn, est, "let");
+									return;
+								};
+							};
+						};
+					};
+				};
+				e = e.next;
+			};
+			return;
+		};
+	};
 	let conf: bool = false;
 	let ok: bool = isassignable(c, n.lhs, src, &conf);
 	if (!conf) { return; };
@@ -11052,6 +11112,13 @@ export fn checkfile(c: *checker, file: *node) void = {
 		} else { if (k == nkind.N_LET) {
 			if (d.lhs != nil) { resolvewalk(c, d.lhs); };
 			if (d.rhs != nil) { resolvewalk(c, d.rhs); };
+			// #130: top-level let assignability — the subtree
+			// resolvewalk above stamps types but never runs the
+			// init-assignability check (function-body lets get it
+			// via resolvewalk's post-order L247; top-level lets
+			// were missed). Needed for the array accept-if-fits
+			// range-check to fire on module-level `let A:[N]u8=[..]`.
+			checkletassign(c, d);
 		};};};};
 		d = d.next;
 	};