diff --git a/lib/pure/asyncmacro.nim b/lib/pure/asyncmacro.nim
index 0ba99cfadabf..5783bde23071 100644
--- a/lib/pure/asyncmacro.nim
+++ b/lib/pure/asyncmacro.nim
@@ -456,15 +456,15 @@ macro multisync*(prc: untyped): untyped =
   result.add(sync)
 
 macro toFutureEx*(prc: typed): untyped =
-  # XXX error instead of asserts
-  #echo repr getRaisesList(prc[0])
-  #assert prc.kind == nnkCall
+  template check(cond: untyped): untyped =
+    if not cond:
+      error("async proc call expected", prc)
+  check prc.kind == nnkCall
+  check prc[0].kind == nnkSym
+  check isAsyncPrc(prc[0].getImpl)
   let procImpl = getTypeImpl(prc[0])
-  #assert procImpl.kind == nnkProcTy
+  check procImpl.kind == nnkProcTy
   let retTyp = procImpl.params[0]
-  #assert retTyp.kind == nnkBracketExpr
-  #let fut = repr(retTyp[0])
-  #assert fut == "FutureUntracked", fut
   let baseTyp = retTyp[1]
   let raisesList = getRaisesList(prc[0])
   let exTyp = if raisesList.len == 0:
diff --git a/tests/async/tasync_error_tracking.nim b/tests/async/tasync_error_tracking.nim
index 929d107c420c..54e5e8cf1867 100644
--- a/tests/async/tasync_error_tracking.nim
+++ b/tests/async/tasync_error_tracking.nim
@@ -45,7 +45,9 @@ block:
     discard
 
 block:
-  # XXX raises: []
+  # we cannot tell if fcb is an async proc
+  # or a closure that returns a user created newFuture()
+  # that can raise anything
   type FooBar = object
     fcb: proc(): Future[void] {.closure, gcsafe.}
 
@@ -123,3 +125,21 @@ block:
       await fut()
   doAssert compiles(good())
   doAssert not compiles(bad())
+
+block:
+  proc bar() {.async.} =
+    err(false)
+
+  # XXX We could check all returns are from async procs
+  #     and if so use the inferred proc raises
+  proc foo(): Future[void] =
+    bar()
+
+  template good =
+    proc main {.async, raises: [Exception].} =
+      await foo()
+  template bad =
+    proc main {.async, raises: [MyError].} =
+      await foo()
+  doAssert compiles(good())
+  doAssert not compiles(bad())