wcc: reject module-scope alloc/call let initializers at check time

A module-scope let whose rhs runs code (alloc, call — peeled through
cast/?/! wrappers) emitted no DATAW slot: emit_lets' fold-fail
silently skipped the definition and every reference died at LINK
time with 'undefined reference', the one unacceptable failure mode
(rule 7). Hare's model rejects at check time (ref/harec/src/
check.c:4360 'Unable to evaluate initializer at compile time') and
routes runtime init through @init, which ww does not have — so both
frontends now reject at the declaration with identical wording.

alias_infptr_global flips compile->error as the alloc pin (its
letvartnode N_TPTR-over-N_TSTRUCT coverage lives on in the local
alias_infptr_{nest,slicecap} siblings); callinit_global_reject pins
the call shape. Corpus pin 1741/345/21/209/1166/3482.

cmd/wcc/check.c

@@ -3126,6 +3126,26 @@ check_file(Checker *c, Node *file)
 			if (t)
 				require_sized(c, t, d->pos, "a variable");
 			d->type = t;
+			/* A module-scope initializer must be link-time data:
+			 * an alloc/call rhs runs code, emit_lets' fold-fail
+			 * skipped the DATAW slot silently, and every
+			 * reference died at LINK time ("undefined reference")
+			 * — reject at the declaration instead (rule 7).
+			 * Hare rejects at check time too (ref/harec/src/
+			 * check.c:4360 "Unable to evaluate initializer at
+			 * compile time"); ww has no @init path. */
+			{
+				Node *r = d->rhs;
+				while (r != NULL && (r->kind == N_CAST
+				    || r->kind == N_TRYPROP
+				    || r->kind == N_TRYUNW))
+					r = r->lhs;
+				if (r != NULL && (r->kind == N_ALLOC
+				    || r->kind == N_CALL))
+					err(c, d->pos, "module-scope let %s: "
+					    "runtime initializer unsupported "
+					    "(alloc/call; rule 7)", d->str);
+			}
 			if (d->str && d->str[0]) {
 				Sym *prev = scope_lookup_local(c->cur, d->str);
 				const char *mod = decl_mod(file, d);

internal/wwfixture/types.ww

@@ -1,13 +1,13 @@
 package wwfixture;
 
 def protocolversion: i32 = 1;
-def corpuscount: i32 = 1740;
-def errorcount: i32 = 343;
-def compilecount: i32 = 22;
+def corpuscount: i32 = 1741;
+def errorcount: i32 = 345;
+def compilecount: i32 = 21;
 def runcount: i32 = 209;
 def runexitcount: i32 = 1166;
-def nativecount: i32 = 3480;
-def corpushash: str = "a2f2514f07ca4e20457331e30f051394da3e59fcfa8f5f6ec3b33d9c14490354";
+def nativecount: i32 = 3482;
+def corpushash: str = "bad5b37d555f3f4d742f7a6fcfa857ff46315757233819a19eb9bc1da2800ce7";
 
 type directive = enum i32 {
 	ERROR = 0,

selfhost/cmd/wcc/check.ww

@@ -343,7 +343,32 @@ fn installdecl(c: *checker, file: *syntax.node, d: *syntax.node) void = {
 	if (k == syntax.nkind.N_DEF)      { installtop(c, d, nm, mod, syntax.skind.SK_DEF,  "def");  return; };
 	if (k == syntax.nkind.N_TYPEDECL) { installtop(c, d, nm, mod, syntax.skind.SK_TYPE, "type"); return; };
 	if (k == syntax.nkind.N_FNDECL)   { installtop(c, d, nm, mod, syntax.skind.SK_FN,   "fn");   return; };
-	if (k == syntax.nkind.N_LET)      { installtop(c, d, nm, mod, syntax.skind.SK_VAR,  "let");  return; };
+	if (k == syntax.nkind.N_LET) {
+		// A module-scope initializer must be link-time data: an
+		// alloc/call rhs runs code, emitletdataw's fold-fail
+		// skipped the DATAW slot silently, and every reference
+		// died at LINK time ("undefined reference") — reject at
+		// the declaration instead (rule 7). Hare rejects at check
+		// time too (ref/harec/src/check.c:4360); ww has no @init
+		// path. Mirrors cstage check_file N_LET.
+		let rr: *syntax.node = d.rhs;
+		for (rr != nil) {
+			if (rr.kind == syntax.nkind.N_CAST) { rr = rr.lhs; continue; };
+			if (rr.kind == syntax.nkind.N_TRYPROP) { rr = rr.lhs; continue; };
+			if (rr.kind == syntax.nkind.N_TRYUNW) { rr = rr.lhs; continue; };
+			break;
+		};
+		if (rr != nil) {
+			if (rr.kind == syntax.nkind.N_ALLOC || rr.kind == syntax.nkind.N_CALL) {
+				cerr(d.file); cerr(": error: module-scope let ");
+				cerr(nm);
+				cerr(": runtime initializer unsupported (alloc/call; rule 7)\n");
+				c.errs += 1;
+			};
+		};
+		installtop(c, d, nm, mod, syntax.skind.SK_VAR, "let");
+		return;
+	};
 };
 
 // installtop — install a top-level decl name into c.top, rejecting a

test/wcc/data/alias_infptr_global/case.ww

@@ -1,6 +1,10 @@
-//ww:compile
-// INFERRED-global *struct root: the letvartnode gate must accept the
-// checker-synthesized N_TPTR-over-N_TSTRUCT exactly as the local arm.
+//ww:error "runtime initializer unsupported (alloc/call; rule 7)"
+// Module-scope alloc initializer: no DATAW slot exists for a
+// runtime-computed global, so pre-reject every reference died at
+// LINK time ("undefined reference to 'main.gp'") — the checker now
+// rejects at the declaration on both frontends (Hare model:
+// ref/harec/src/check.c:4360 rejects non-compile-time-evaluable
+// global initializers; ww has no @init path).
 package main;
 type box = struct { s: str, n: int };
 let gp = alloc(box { s = "hi", n = 1 })!;

test/wcc/data/callinit_global_reject/case.ww

@@ -0,0 +1,7 @@
+//ww:error "runtime initializer unsupported (alloc/call; rule 7)"
+// The call sibling of alias_infptr_global's alloc reject: a
+// module-scope call initializer has no link-time data either.
+package main;
+fn mk() i64 = { return 7; };
+let gc: i64 = mk();
+export fn main() i32 = { return gc: i32; };