Implement deterministic collapse of 'await' in 'await using' (#262)

Author: rbuckton

tslib.es6.js

@@ -327,17 +327,22 @@ export function __disposeResources(env) {
         env.error = env.hasError ? new _SuppressedError(e, env.error, "An error was suppressed during disposal.") : e;
         env.hasError = true;
     }
+    var r, s = 0;
     function next() {
-        while (env.stack.length) {
-            var rec = env.stack.pop();
+        while (r = env.stack.pop()) {
             try {
-                var result = rec.dispose && rec.dispose.call(rec.value);
-                if (rec.async) return Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                if (!r.async && s === 1) return s = 0, env.stack.push(r), Promise.resolve().then(next);
+                if (r.dispose) {
+                    var result = r.dispose.call(r.value);
+                    if (r.async) return s |= 2, Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                }
+                else s |= 1;
             }
             catch (e) {
                 fail(e);
             }
         }
+        if (s === 1) return env.hasError ? Promise.reject(env.error) : Promise.resolve();
         if (env.hasError) throw env.error;
     }
     return next();

tslib.es6.mjs

@@ -326,17 +326,22 @@ export function __disposeResources(env) {
     env.error = env.hasError ? new _SuppressedError(e, env.error, "An error was suppressed during disposal.") : e;
     env.hasError = true;
   }
+  var r, s = 0;
   function next() {
-    while (env.stack.length) {
-      var rec = env.stack.pop();
+    while (r = env.stack.pop()) {
       try {
-        var result = rec.dispose && rec.dispose.call(rec.value);
-        if (rec.async) return Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+        if (!r.async && s === 1) return s = 0, env.stack.push(r), Promise.resolve().then(next);
+        if (r.dispose) {
+          var result = r.dispose.call(r.value);
+          if (r.async) return s |= 2, Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+        }
+        else s |= 1;
       }
       catch (e) {
-          fail(e);
+        fail(e);
       }
     }
+    if (s === 1) return env.hasError ? Promise.reject(env.error) : Promise.resolve();
     if (env.hasError) throw env.error;
   }
   return next();

tslib.js

@@ -374,17 +374,22 @@ var __disposeResources;
             env.error = env.hasError ? new _SuppressedError(e, env.error, "An error was suppressed during disposal.") : e;
             env.hasError = true;
         }
+        var r, s = 0;
         function next() {
-            while (env.stack.length) {
-                var rec = env.stack.pop();
+            while (r = env.stack.pop()) {
                 try {
-                    var result = rec.dispose && rec.dispose.call(rec.value);
-                    if (rec.async) return Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                    if (!r.async && s === 1) return s = 0, env.stack.push(r), Promise.resolve().then(next);
+                    if (r.dispose) {
+                        var result = r.dispose.call(r.value);
+                        if (r.async) return s |= 2, Promise.resolve(result).then(next, function(e) { fail(e); return next(); });
+                    }
+                    else s |= 1;
                 }
                 catch (e) {
                     fail(e);
                 }
             }
+            if (s === 1) return env.hasError ? Promise.reject(env.error) : Promise.resolve();
             if (env.hasError) throw env.error;
         }
         return next();