Less fragile test

src/__tests__/compiler.test.ts

@@ -1,8 +1,9 @@
 import { e2eVoidText, gcVoidText, tcoText } from "./fixtures/e2e-file.js";
 import { compile } from "../compiler.js";
-import { describe, expect, test } from "vitest";
+import { describe, expect, test, vi } from "vitest";
 import assert from "node:assert";
 import { getWasmFn, getWasmInstance } from "../lib/wasm.js";
+import * as rCallUtil from "../assembler/return-call.js";
 
 describe("E2E Compiler Pipeline", () => {
   test("Compiler can compile and run a basic void program", async (t) => {
@@ -37,8 +38,8 @@ describe("E2E Compiler Pipeline", () => {
   });
 
   test("Compiler can do tco", async (t) => {
-    const mod = await compile(tcoText);
-    mod.optimize();
-    t.expect(mod.emitText()).toMatchSnapshot();
+    const spy = vi.spyOn(rCallUtil, "returnCall");
+    await compile(tcoText);
+    t.expect(spy).toHaveBeenCalledTimes(1);
   });
 });

src/assembler.ts

@@ -21,6 +21,7 @@ import { HeapTypeRef } from "./lib/binaryen-gc/types.js";
 import { getExprType } from "./semantics/resolution/get-expr-type.js";
 import { Match, MatchCase } from "./syntax-objects/match.js";
 import { initExtensionHelpers } from "./assembler/extension-helpers.js";
+import { returnCall } from "./assembler/return-call.js";
 
 export const assemble = (ast: Expr) => {
   const mod = new binaryen.Module();
@@ -182,7 +183,7 @@ const compileCall = (opts: CompileExprOpts<Call>): number => {
   const returnType = mapBinaryenType(opts, expr.fn!.returnType!);
 
   if (isReturnExpr && id === expr.parentFn?.id) {
-    return mod.return_call(id, args, returnType);
+    return returnCall(mod, id, args, returnType);
   }
 
   return mod.call(id, args, returnType);

src/assembler/return-call.ts

@@ -0,0 +1,11 @@
+import binaryen from "binaryen";
+import { ExpressionRef, TypeRef } from "../lib/binaryen-gc/types.js";
+
+export const returnCall = (
+  mod: binaryen.Module,
+  fnId: string,
+  args: ExpressionRef[],
+  returnType: TypeRef
+) => {
+  return mod.return_call(fnId, args, returnType);
+};