Update native emission fixtures for direct joins

- Exercise the current scalar join helper and verify reuse.
- Preserve native and Node emission and refusal contracts.

tests/fixtures/self-hosting/llvm-layouts.ts

@@ -16,7 +16,6 @@ interface Request {
   classObjects: string[];
   sources: { file: string; text: string }[];
   writers?: IrType[];
-  textUnions?: string[];
   joinUnions?: string[];
   indent?: boolean;
 }
@@ -69,7 +68,6 @@ try {
   const walkers = new LlWalkers(host);
   const helpers: string[] = [];
   for (const type of request.writers ?? []) helpers.push(walkers.jsonWriteHelper(type));
-  for (const union of request.textUnions ?? []) helpers.push(walkers.unionToStrHelper(union));
   for (const union of request.joinUnions ?? []) helpers.push(walkers.unionJoinHelper(union));
   if (request.indent) helpers.push(walkers.jsonIndentHelper());
   const classes = [...graph.values()].map((meta) => ({

tests/harness/self-hosting-emission-cases.ts

@@ -20,7 +20,6 @@ export interface EmissionRequest {
   classObjects: string[];
   sources: { file: string; text: string }[];
   writers?: IrType[];
-  textUnions?: string[];
   joinUnions?: string[];
   indent?: boolean;
 }
@@ -322,12 +321,11 @@ export function emissionCases(): EmissionCase[] {
   textUnion.unions = [{ id: "text", arms: [BOOL, F64, STRING, { kind: "nullT" }, UNDEFINED_T] }];
   const textRequest = emissionRequest();
   textRequest.writers = [{ kind: "union", unionId: "text" }];
-  textRequest.textUnions = ["text", "text"];
-  textRequest.joinUnions = ["text"];
+  textRequest.joinUnions = ["text", "text"];
   add(
-    "union JSON, string and join helpers",
+    "union JSON and direct join helpers",
     textUnion,
-    ["switch i32", "@scr_str_retain"],
+    ["switch i32", "@scr_arr_peek_ref", "@scr_jb_put_number"],
     textRequest,
   );
 

tests/harness/self-hosting-emission.test.ts

@@ -119,6 +119,9 @@ for (const backend of ["llvm"] as const) {
           emitted.debug,
         ].join("\n");
         for (const expected of item.contains) expect(definitions, item.name).toContain(expected);
+        if ((item.request.joinUnions?.length ?? 0) > 1) {
+          expect(definitions.match(/define internal ptr @sc_uj_/g), item.name).toHaveLength(1);
+        }
         if (item.name.startsWith("class forest")) {
           expect(
             emitted.classes.map((meta) => [meta.name, meta.root, meta.pre, meta.post]),
@@ -167,10 +170,6 @@ for (const backend of ["llvm"] as const) {
           request: { ...emissionRequest(), writers: [{ kind: "union", unionId: "Missing" }] },
           message: "jsonStringify of unknown union Missing",
         },
-        {
-          request: { ...emissionRequest(), textUnions: ["Missing"] },
-          message: "ToString of unknown union Missing",
-        },
         {
           request: { ...emissionRequest(), joinUnions: ["Missing"] },
           message: "join of unknown union Missing",
@@ -189,11 +188,11 @@ for (const backend of ["llvm"] as const) {
       expect(
         run(
           unsupported,
-          { ...emissionRequest(), textUnions: ["containers"] },
-          "unsupported union stringification",
+          { ...emissionRequest(), joinUnions: ["containers"] },
+          "unsupported union join",
           1,
         ),
-      ).toContain("unionToStr:array");
+      ).toContain("unionJoin:array");
 
       for (const source of [
         "711-inheritance-dispatch.ts",