Fix runtime eval temp variable collision

runtime/index.js

@@ -18,8 +18,9 @@ function uid() {
 
 function safeEval(code, inputs, __setEcho__) {
   const create = (code) => {
+    const resultVar = `__recho_v_${uid()}`;
     // Ensure the current echo function is bound for the executing cell.
-    const body = `__setEcho__(echo); const __foo__ = ${code}; const v = __foo__(${inputs.join(",")}); __setEcho__(null); return v;`;
+    const body = `__setEcho__(echo); const __foo__ = ${code}; const ${resultVar} = __foo__(${inputs.join(",")}); __setEcho__(null); return ${resultVar};`;
     const fn = new Function("__setEcho__", ...inputs, body);
     return (...args) => fn(__setEcho__, ...args);
   };

test/js/index-tests.js

@@ -19,3 +19,4 @@ export {echoInRecursiveFunction} from "./echo-in-recursive-function.js";
 export {echoInBracket} from "./echo-in-bracket.js";
 export {echoAsParams} from "./echo-as-params.js";
 export {echoKey} from "./echo-key.js";
+export {vCollision} from "./v-collision.js";

test/js/index.js

@@ -32,3 +32,4 @@ export {echoInBlock} from "./echo-in-block.js";
 export {echoInAsyncCallback} from "./echo-in-async-callback.js";
 export {echoInBracket} from "./echo-in-bracket.js";
 export {echoAsParams} from "./echo-as-params.js";
+export {vCollision} from "./v-collision.js";

test/js/v-collision.js

@@ -0,0 +1,4 @@
+export const vCollision = `const v = 123;
+
+echo(v);
+`;

test/output/vCollision.js

@@ -0,0 +1,4 @@
+const v = 123;
+
+//➜ 123
+echo(v);