diff --git a/src/core/corelib.c b/src/core/corelib.c
index 52d445f3..9c03f51c 100644
--- a/src/core/corelib.c
+++ b/src/core/corelib.c
@@ -653,22 +653,15 @@ JANET_CORE_FN(janet_core_check_int,
               "(int? x)",
               "Check if x can be exactly represented as a 32 bit signed two's complement integer.") {
     janet_fixarity(argc, 1);
-    if (!janet_checktype(argv[0], JANET_NUMBER)) goto ret_false;
-    double num = janet_unwrap_number(argv[0]);
-    return janet_wrap_boolean(num == (double)((int32_t)num));
-ret_false:
-    return janet_wrap_false();
+    return janet_wrap_boolean(janet_checkint(argv[0]));
 }
 
 JANET_CORE_FN(janet_core_check_nat,
               "(nat? x)",
               "Check if x can be exactly represented as a non-negative 32 bit signed two's complement integer.") {
     janet_fixarity(argc, 1);
-    if (!janet_checktype(argv[0], JANET_NUMBER)) goto ret_false;
-    double num = janet_unwrap_number(argv[0]);
-    return janet_wrap_boolean(num >= 0 && (num == (double)((int32_t)num)));
-ret_false:
-    return janet_wrap_false();
+    if (!janet_checkint(argv[0])) return janet_wrap_false();
+    return janet_wrap_boolean(janet_unwrap_integer(argv[0]) >= 0);
 }
 
 JANET_CORE_FN(janet_core_is_bytes,
diff --git a/src/core/ev.c b/src/core/ev.c
index d0fbca56..78fe96dd 100644
--- a/src/core/ev.c
+++ b/src/core/ev.c
@@ -671,11 +671,9 @@ static DWORD WINAPI janet_timeout_body(LPVOID ptr) {
     JanetThreadedTimeout tto = *(JanetThreadedTimeout *)ptr;
     janet_free(ptr);
     SleepEx((DWORD)(tto.sec * 1000), TRUE);
-    if (janet_fiber_can_resume(tto.fiber)) {
-        janet_interpreter_interrupt(tto.vm);
-        JanetEVGenericMessage msg = {0};
-        janet_ev_post_event(tto.vm, janet_timeout_cb, msg);
-    }
+    janet_interpreter_interrupt(tto.vm);
+    JanetEVGenericMessage msg = {0};
+    janet_ev_post_event(tto.vm, janet_timeout_cb, msg);
     return 0;
 }
 #else
@@ -696,11 +694,9 @@ static void *janet_timeout_body(void *ptr) {
                  ? (long)((tto.sec - ((uint32_t)tto.sec)) * 1000000000)
                  : 0;
     nanosleep(&ts, &ts);
-    if (janet_fiber_can_resume(tto.fiber)) {
-        janet_interpreter_interrupt(tto.vm);
-        JanetEVGenericMessage msg = {0};
-        janet_ev_post_event(tto.vm, janet_timeout_cb, msg);
-    }
+    janet_interpreter_interrupt(tto.vm);
+    JanetEVGenericMessage msg = {0};
+    janet_ev_post_event(tto.vm, janet_timeout_cb, msg);
     return NULL;
 }
 #endif