diff --git a/base/task.jl b/base/task.jl
index bfb105accef14..e84c344c28d17 100644
--- a/base/task.jl
+++ b/base/task.jl
@@ -721,6 +721,7 @@ A fast, unfair-scheduling version of `schedule(t, arg); yield()` which
 immediately yields to `t` before calling the scheduler.
 """
 function yield(t::Task, @nospecialize(x=nothing))
+    (t._state === task_state_runnable && t.queue === nothing) || error("yield: Task not runnable")
     t.result = x
     enq_work(current_task())
     set_next_task(t)
@@ -736,6 +737,13 @@ call to `yieldto`. This is a low-level call that only switches tasks, not consid
 or scheduling in any way. Its use is discouraged.
 """
 function yieldto(t::Task, @nospecialize(x=nothing))
+    # TODO: these are legacy behaviors; these should perhaps be a scheduler
+    # state error instead.
+    if t._state === task_state_done
+        return x
+    elseif t._state === task_state_failed
+        throw(t.result)
+    end
     t.result = x
     set_next_task(t)
     return try_yieldto(identity)
diff --git a/src/task.c b/src/task.c
index 24081dfc6c4b3..43ab8db89cfee 100644
--- a/src/task.c
+++ b/src/task.c
@@ -475,12 +475,8 @@ JL_DLLEXPORT void jl_switch(void)
     if (t == ct) {
         return;
     }
-    if (t->_state != JL_TASK_STATE_RUNNABLE || (t->started && t->stkbuf == NULL)) {
-        ct->_isexception = t->_isexception;
-        ct->result = t->result;
-        jl_gc_wb(ct, ct->result);
-        return;
-    }
+    if (t->started && t->stkbuf == NULL)
+        jl_error("attempt to switch to exited task");
     if (ptls->in_finalizer)
         jl_error("task switch not allowed from inside gc finalizer");
     if (ptls->in_pure_callback)
diff --git a/test/misc.jl b/test/misc.jl
index 2305b78250ef2..37c5397b4948f 100644
--- a/test/misc.jl
+++ b/test/misc.jl
@@ -182,6 +182,17 @@ end
 
 @test_throws ErrorException("deadlock detected: cannot wait on current task") wait(current_task())
 
+# issue #41347
+let t = @async 1
+    wait(t)
+    @test_throws ErrorException yield(t)
+end
+
+let t = @async error(42)
+    Base._wait(t)
+    @test_throws ErrorException("42") yieldto(t)
+end
+
 # test that @sync is lexical (PR #27164)
 
 const x27164 = Ref(0)