diff --git a/compiler/semmacrosanity.nim b/compiler/semmacrosanity.nim
index 02c56c0354..3056f5d721 100644
--- a/compiler/semmacrosanity.nim
+++ b/compiler/semmacrosanity.nim
@@ -88,7 +88,7 @@ proc annotateType*(n: PNode, t: PType; conf: ConfigRef) =
     else:
       globalError(conf, n.info, "string literal must be of some string type")
   of nkNilLit:
-    if x.kind in NilableTypes:
+    if x.kind in NilableTypes+{tyString, tySequence}:
       n.typ = t
     else:
       globalError(conf, n.info, "nil literal must be of some pointer type")
diff --git a/lib/system.nim b/lib/system.nim
index 4b69a80673..c730167ede 100644
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -2344,8 +2344,12 @@ proc `==`*[T](x, y: seq[T]): bool {.noSideEffect.} =
   ## Generic equals operator for sequences: relies on a equals operator for
   ## the element type `T`.
   when nimvm:
-    if x.isNil and y.isNil:
-      return true
+    when not defined(nimNoNil):
+      if x.isNil and y.isNil:
+        return true
+    else:
+      if x.len == 0 and y.len == 0:
+        return true
   else:
     when not defined(JS):
       proc seqToPtr[T](x: seq[T]): pointer {.inline, nosideeffect.} =
diff --git a/tests/cpp/tasync_cpp.nim b/tests/cpp/tasync_cpp.nim
index a5e3374b6a..50bc1853ce 100644
--- a/tests/cpp/tasync_cpp.nim
+++ b/tests/cpp/tasync_cpp.nim
@@ -1,6 +1,7 @@
 discard """
   targets: "cpp"
   output: "hello"
+  cmd: "nim cpp --nilseqs:on $file"
 """
 
 # bug #3299
diff --git a/tests/distinct/tnil.nim b/tests/distinct/tnil.nim
index 759a14657a..16de38f603 100644
--- a/tests/distinct/tnil.nim
+++ b/tests/distinct/tnil.nim
@@ -9,7 +9,6 @@ discard """
 type
   MyPointer = distinct pointer
   MyString = distinct string
-  MyStringNotNil = distinct (string not nil)
   MyInt = distinct int
 
 proc foo(a: MyPointer) =
@@ -26,20 +25,6 @@ p = cast[MyPointer](nil)
 p = nil.MyPointer
 p = nil
 
-var c: MyString
-c = "Test".MyString
-c = nil.MyString
-c = nil
-
-p = nil
-doAssert(compiles(c = p) == false)
-
-var n: MyStringNotNil = "Test".MyStringNotNil # Cannot prove warning ...
-n = "Test".MyStringNotNil
-doAssert(compiles(n = nil.MyStringNotNil) == false)
-doAssert(compiles(n = nil.MyStringNotNil) == false)
-doAssert(compiles(n = nil) == false)
-
 var i: MyInt
 i = 1.MyInt
 doAssert(compiles(i = nil) == false)
diff --git a/tests/notnil/tmust_compile.nim b/tests/notnil/tmust_compile.nim
index a32c6c7ecd..d09dda0575 100644
--- a/tests/notnil/tmust_compile.nim
+++ b/tests/notnil/tmust_compile.nim
@@ -44,16 +44,16 @@ import json
 type
 
   foo = object
-    thing: string not nil
+    thing: ptr int not nil
 
   CTS = ref object
     subs_by_sid: Table[int, foo]
 
 
 proc parse(cts: CTS, jn: JsonNode) =
-
+  var y = jn.getInt(4523)
   let ces = foo(
-    thing: jn.getStr("thing")
+    thing: addr y
   )
 
   cts.subs_by_sid[0] = ces
@@ -63,17 +63,3 @@ proc parse(cts: CTS, jn: JsonNode) =
 
 proc p(x: proc(){.closure.} not nil) = discard
 p(proc(){.closure.} = discard)
-
-# bug #3993
-
-type
-  List[T] = seq[T] not nil
-
-proc `^^`[T](v: T, lst: List[T]): List[T] =
-  result = @[v]
-  result.add(lst)
-
-proc Nil[T](): List[T] = @[]
-
-when isMainModule:
-  let lst = 1 ^^ 2 ^^ Nil[int]()
diff --git a/tests/notnil/tnotnil1.nim b/tests/notnil/tnotnil1.nim
index 7f9d022958..60666d64d4 100644
--- a/tests/notnil/tnotnil1.nim
+++ b/tests/notnil/tnotnil1.nim
@@ -1,6 +1,6 @@
 discard """
   errormsg: "'y' is provably nil"
-  line:38
+  line:25
 """
 
 import strutils
@@ -10,19 +10,6 @@ type
   TObj = object
     x, y: int
 
-type
-  superstring = string not nil
-
-
-proc q(s: superstring) =
-  echo s
-
-proc p2() =
-  var a: string = "I am not nil"
-  q(a) # but this should and does not
-
-p2()
-
 proc q(x: pointer not nil) =
   discard
 
diff --git a/tests/notnil/tnotnil_in_objconstr.nim b/tests/notnil/tnotnil_in_objconstr.nim
index d33709906b..f0d5c1ae20 100644
--- a/tests/notnil/tnotnil_in_objconstr.nim
+++ b/tests/notnil/tnotnil_in_objconstr.nim
@@ -6,9 +6,9 @@ discard """
 # bug #2355
 type
   Foo = object
-    foo: string not nil
-    bar: string not nil
-
+    foo: ref int
+    bar: ref int not nil
+var x: ref int = new(int)
 # Create instance without initializaing the `bar` field
-var f = Foo(foo: "foo")
+var f = Foo(foo: x)
 echo f.bar.isNil # true
diff --git a/tests/vm/tseq_badinit.nim b/tests/vm/tseq_badinit.nim
index 15889d60ec..5fa223c85b 100644
--- a/tests/vm/tseq_badinit.nim
+++ b/tests/vm/tseq_badinit.nim
@@ -22,14 +22,14 @@ template test(typename, default: untyped) =
     result = newSeq[typename]()
     result.add(default)
     result.setLen(3)
-    for i in 0 .. <2:
+    for i in 0 ..< 2:
       result[i] = default
 
   const constval = `abc typename`()
   doAssert(constval == `abc typename`())
 
   proc `arr typename`(): array[4, typename] =
-    for i in 0 .. <2:
+    for i in 0 ..< 2:
       result[i] = default
   const constarr = `arr typename`()
   doAssert(constarr == `arr typename`())