diff --git a/CHANGELOG.md b/CHANGELOG.md
index fcdf8236a6..637f479aad 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,7 @@
 
 - In type errors, recommend stdlib over Belt functions for converting between float/int/string. https://github.com/rescript-lang/rescript/pull/7453
 - Remove unused type `Jsx.ref`. https://github.com/rescript-lang/rescript/pull/7459
+- Add `@notUndefined` attribute to all relevant abstract types in `Stdlib`. https://github.com/rescript-lang/rescript/pull/7464
 
 # 12.0.0-alpha.12
 
diff --git a/runtime/Stdlib_ArrayBuffer.res b/runtime/Stdlib_ArrayBuffer.res
index 2b0cf3a36b..4b672e196d 100644
--- a/runtime/Stdlib_ArrayBuffer.res
+++ b/runtime/Stdlib_ArrayBuffer.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 @new external make: int => t = "ArrayBuffer"
diff --git a/runtime/Stdlib_AsyncIterator.res b/runtime/Stdlib_AsyncIterator.res
index 03504dafc0..b62128c821 100644
--- a/runtime/Stdlib_AsyncIterator.res
+++ b/runtime/Stdlib_AsyncIterator.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t<'a>
 
 type value<'a> = {
diff --git a/runtime/Stdlib_AsyncIterator.resi b/runtime/Stdlib_AsyncIterator.resi
index 50db4fdf3b..5d2e9b6dcf 100644
--- a/runtime/Stdlib_AsyncIterator.resi
+++ b/runtime/Stdlib_AsyncIterator.resi
@@ -6,6 +6,7 @@ See [async iterator protocols](https://developer.mozilla.org/en-US/docs/Web/Java
 /**
 The type representing an async iterator.
 */
+@notUndefined
 type t<'a>
 
 type value<'a> = {
diff --git a/runtime/Stdlib_DataView.res b/runtime/Stdlib_DataView.res
index 8ab0025336..2c0ccd91bf 100644
--- a/runtime/Stdlib_DataView.res
+++ b/runtime/Stdlib_DataView.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 @new external fromBuffer: Stdlib_ArrayBuffer.t => t = "DataView"
diff --git a/runtime/Stdlib_Intl_Collator.res b/runtime/Stdlib_Intl_Collator.res
index f457c247f7..4329a6f1c5 100644
--- a/runtime/Stdlib_Intl_Collator.res
+++ b/runtime/Stdlib_Intl_Collator.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 type usage = [#sort | #search]
diff --git a/runtime/Stdlib_Intl_DateTimeFormat.res b/runtime/Stdlib_Intl_DateTimeFormat.res
index 9c2be84b11..00992bee49 100644
--- a/runtime/Stdlib_Intl_DateTimeFormat.res
+++ b/runtime/Stdlib_Intl_DateTimeFormat.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 type dateStyle = [#full | #long | #medium | #short]
diff --git a/runtime/Stdlib_Intl_ListFormat.res b/runtime/Stdlib_Intl_ListFormat.res
index 3dd0b280e6..3f4b0cb41f 100644
--- a/runtime/Stdlib_Intl_ListFormat.res
+++ b/runtime/Stdlib_Intl_ListFormat.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 type listType = [
diff --git a/runtime/Stdlib_Intl_Locale.res b/runtime/Stdlib_Intl_Locale.res
index 45c9388e29..f250413f53 100644
--- a/runtime/Stdlib_Intl_Locale.res
+++ b/runtime/Stdlib_Intl_Locale.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 type options = {
diff --git a/runtime/Stdlib_Intl_NumberFormat.res b/runtime/Stdlib_Intl_NumberFormat.res
index f69d7f1148..4962de43d4 100644
--- a/runtime/Stdlib_Intl_NumberFormat.res
+++ b/runtime/Stdlib_Intl_NumberFormat.res
@@ -1,5 +1,6 @@
 module Grouping = Stdlib_Intl_NumberFormat_Grouping
 
+@notUndefined
 type t
 
 /**
@@ -211,7 +212,7 @@ external formatBigIntRangeToParts: (t, ~start: bigint, ~end: bigint) => array<nu
 external formatStringToParts: (t, string) => array<numberFormatRangePart> = "formatToParts"
 
 /**
-  `ignore(numberGrouping)` ignores the provided numberGrouping and returns unit.
+  `ignore(numberFormat)` ignores the provided numberFormat and returns unit.
 
   This helper is useful when you want to discard a value (for example, the result of an operation with side effects)
   without having to store or process it further.
diff --git a/runtime/Stdlib_Intl_NumberFormat_Grouping.res b/runtime/Stdlib_Intl_NumberFormat_Grouping.res
index 47227b6e7f..f0b0c82a4a 100644
--- a/runtime/Stdlib_Intl_NumberFormat_Grouping.res
+++ b/runtime/Stdlib_Intl_NumberFormat_Grouping.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 type parsed = [#bool(bool) | #always | #auto | #min2]
diff --git a/runtime/Stdlib_Intl_PluralRules.res b/runtime/Stdlib_Intl_PluralRules.res
index 8e52f7d98a..49348b9aac 100644
--- a/runtime/Stdlib_Intl_PluralRules.res
+++ b/runtime/Stdlib_Intl_PluralRules.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 type localeType = [#cardinal | #ordinal]
diff --git a/runtime/Stdlib_Intl_RelativeTimeFormat.res b/runtime/Stdlib_Intl_RelativeTimeFormat.res
index f3173520d7..2454473e36 100644
--- a/runtime/Stdlib_Intl_RelativeTimeFormat.res
+++ b/runtime/Stdlib_Intl_RelativeTimeFormat.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 type numeric = [#always | #auto]
diff --git a/runtime/Stdlib_Intl_Segmenter.res b/runtime/Stdlib_Intl_Segmenter.res
index fd79657ef0..16bf7a2c07 100644
--- a/runtime/Stdlib_Intl_Segmenter.res
+++ b/runtime/Stdlib_Intl_Segmenter.res
@@ -1,6 +1,4 @@
-/***
-Not supported in Firefox
-*/
+@notUndefined
 type t
 
 type granularity = [#grapheme | #word | #sentence]
diff --git a/runtime/Stdlib_Intl_Segments.res b/runtime/Stdlib_Intl_Segments.res
index 32b0d4cb0e..39f2ff7269 100644
--- a/runtime/Stdlib_Intl_Segments.res
+++ b/runtime/Stdlib_Intl_Segments.res
@@ -2,6 +2,7 @@
  A Segments instance is an object that represents the segments of a specific string, subject to the locale and options of its constructing Intl.Segmenter instance.
 https://tc39.es/ecma402/#sec-segments-objects
 */
+@notUndefined
 type t
 
 type segmentData = {
diff --git a/runtime/Stdlib_Iterator.res b/runtime/Stdlib_Iterator.res
index f631b604d1..01d14aa5a1 100644
--- a/runtime/Stdlib_Iterator.res
+++ b/runtime/Stdlib_Iterator.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t<'a>
 
 type value<'a> = {
diff --git a/runtime/Stdlib_Iterator.resi b/runtime/Stdlib_Iterator.resi
index 359039a588..91e43fe00e 100644
--- a/runtime/Stdlib_Iterator.resi
+++ b/runtime/Stdlib_Iterator.resi
@@ -7,6 +7,7 @@ See [`iterator protocols`](https://developer.mozilla.org/en-US/docs/Web/JavaScri
 /**
 The type representing an iterator.
 */
+@notUndefined
 type t<'a>
 
 /**
diff --git a/runtime/Stdlib_JsError.res b/runtime/Stdlib_JsError.res
index 17ff192439..0622973178 100644
--- a/runtime/Stdlib_JsError.res
+++ b/runtime/Stdlib_JsError.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 @get external stack: t => option<string> = "stack"
diff --git a/runtime/Stdlib_JsError.resi b/runtime/Stdlib_JsError.resi
index 9f55fd7a82..2304cf9569 100644
--- a/runtime/Stdlib_JsError.resi
+++ b/runtime/Stdlib_JsError.resi
@@ -5,6 +5,7 @@ See [`Error`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/
 */
 
 /** Represents a JavaScript error. */
+@notUndefined
 type t
 
 /**
diff --git a/runtime/Stdlib_Map.res b/runtime/Stdlib_Map.res
index 2a4ea8d8ca..7d534aa7d8 100644
--- a/runtime/Stdlib_Map.res
+++ b/runtime/Stdlib_Map.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t<'k, 'v>
 
 @new external make: unit => t<'k, 'v> = "Map"
diff --git a/runtime/Stdlib_Map.resi b/runtime/Stdlib_Map.resi
index 3fc56d3f1a..3df63191e3 100644
--- a/runtime/Stdlib_Map.resi
+++ b/runtime/Stdlib_Map.resi
@@ -7,6 +7,7 @@ See [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Gl
 /**
 Type representing an instance of `Map`.
 */
+@notUndefined
 type t<'k, 'v>
 
 /**
diff --git a/runtime/Stdlib_Pair.res b/runtime/Stdlib_Pair.res
index 767ad280ff..745bad6557 100644
--- a/runtime/Stdlib_Pair.res
+++ b/runtime/Stdlib_Pair.res
@@ -27,7 +27,7 @@ Pair.second((1, 2))->assertEqual(2)
 external second: (('a, 'b)) => 'b = "%field1"
 
 /**
-  `ignore(option)` ignores the provided pair and returns unit.
+  `ignore(pair)` ignores the provided pair and returns unit.
 
   This helper is useful when you want to discard a value (for example, the result of an operation with side effects)
   without having to store or process it further.
diff --git a/runtime/Stdlib_Set.res b/runtime/Stdlib_Set.res
index 724058afb1..61040dc863 100644
--- a/runtime/Stdlib_Set.res
+++ b/runtime/Stdlib_Set.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t<'a>
 
 @new external make: unit => t<'a> = "Set"
diff --git a/runtime/Stdlib_Set.resi b/runtime/Stdlib_Set.resi
index 9437fe85e1..4945add4d1 100644
--- a/runtime/Stdlib_Set.resi
+++ b/runtime/Stdlib_Set.resi
@@ -7,6 +7,7 @@ See [`Set`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Gl
 /**
 Type representing an instance of `Set`.
 */
+@notUndefined
 type t<'a>
 
 /**
diff --git a/runtime/Stdlib_Symbol.res b/runtime/Stdlib_Symbol.res
index 195f82cfe9..bbdb978313 100644
--- a/runtime/Stdlib_Symbol.res
+++ b/runtime/Stdlib_Symbol.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t
 
 @val external make: string => t = "Symbol"
diff --git a/runtime/Stdlib_Symbol.resi b/runtime/Stdlib_Symbol.resi
index 5dceef04c3..3a2bf3bf17 100644
--- a/runtime/Stdlib_Symbol.resi
+++ b/runtime/Stdlib_Symbol.resi
@@ -7,6 +7,7 @@ Compiles to a regular JavaScript Symbol.
 /**
 Type representing a Symbol.
 */
+@notUndefined
 type t
 
 /**
@@ -28,7 +29,7 @@ external make: string => t = "Symbol"
 /**
 `getFor(key)`
 
-Searches for existing registered Symbols in the global Symbol registry with the given key and returns it if found. 
+Searches for existing registered Symbols in the global Symbol registry with the given key and returns it if found.
 Otherwise a new Symbol gets created and registered with key.
 
 ## Examples
diff --git a/runtime/Stdlib_TypedArray.res b/runtime/Stdlib_TypedArray.res
index 2d9a5add76..759f81cb18 100644
--- a/runtime/Stdlib_TypedArray.res
+++ b/runtime/Stdlib_TypedArray.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t<'a>
 
 @get_index external get: (t<'a>, int) => option<'a> = ""
diff --git a/runtime/Stdlib_WeakMap.res b/runtime/Stdlib_WeakMap.res
index f6846eb17a..9fd4e99c82 100644
--- a/runtime/Stdlib_WeakMap.res
+++ b/runtime/Stdlib_WeakMap.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t<'k, 'v>
 
 @new external make: unit => t<'k, 'v> = "WeakMap"
diff --git a/runtime/Stdlib_WeakSet.res b/runtime/Stdlib_WeakSet.res
index 6d6deefdfd..5316552323 100644
--- a/runtime/Stdlib_WeakSet.res
+++ b/runtime/Stdlib_WeakSet.res
@@ -1,3 +1,4 @@
+@notUndefined
 type t<'a>
 
 @new external make: unit => t<'a> = "WeakSet"
diff --git a/tests/tests/src/core/intl/Core_Intl_NumberFormatTest.mjs b/tests/tests/src/core/intl/Core_Intl_NumberFormatTest.mjs
index 988d5795bb..132cd9709b 100644
--- a/tests/tests/src/core/intl/Core_Intl_NumberFormatTest.mjs
+++ b/tests/tests/src/core/intl/Core_Intl_NumberFormatTest.mjs
@@ -1,6 +1,5 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
-import * as Primitive_option from "rescript/lib/es6/Primitive_option.js";
 import * as Stdlib_Intl_NumberFormat_Grouping from "rescript/lib/es6/Stdlib_Intl_NumberFormat_Grouping.js";
 
 console.log("---");
@@ -26,7 +25,7 @@ let roundingFormatter = new Intl.NumberFormat(undefined, {
 });
 
 let groupingFormatter1 = new Intl.NumberFormat(undefined, {
-  useGrouping: Primitive_option.some(true)
+  useGrouping: true
 });
 
 let groupingFormatter2 = new Intl.NumberFormat(undefined, {
diff --git a/tests/tests/src/internal_unused_test.res b/tests/tests/src/internal_unused_test.res
index 437c3cf754..23a11190e0 100644
--- a/tests/tests/src/internal_unused_test.res
+++ b/tests/tests/src/internal_unused_test.res
@@ -17,7 +17,7 @@ module P1 = {
 }
 open! P1
 
-let f = () => raise(A)
+let f = () => throw(A)
 
 %%private(let b = 3)
 
diff --git a/tests/tests/src/option_wrapping_test.mjs b/tests/tests/src/option_wrapping_test.mjs
index 4efe8a0437..1f04be7cd7 100644
--- a/tests/tests/src/option_wrapping_test.mjs
+++ b/tests/tests/src/option_wrapping_test.mjs
@@ -1,6 +1,8 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
+import * as Stdlib_Lazy from "rescript/lib/es6/Stdlib_Lazy.js";
 import * as Primitive_option from "rescript/lib/es6/Primitive_option.js";
+import * as Stdlib_AsyncIterator from "rescript/lib/es6/Stdlib_AsyncIterator.js";
 
 let x6 = {
   x: 42
@@ -24,6 +26,54 @@ let x21 = new Date();
 
 let x22 = /test/;
 
+let x23 = new Map();
+
+let x24 = new Set();
+
+let x25 = new WeakMap();
+
+let x26 = new WeakSet();
+
+let x27 = new Float32Array([1.0]);
+
+let x28 = Symbol("");
+
+let x29 = new Error("");
+
+let x30 = new ArrayBuffer(0);
+
+let x31 = new DataView(new ArrayBuffer(0));
+
+let x32 = new Map().values();
+
+let x33 = Stdlib_AsyncIterator.make(() => Promise.resolve(Stdlib_AsyncIterator.value(true)));
+
+let x34 = new Intl.ListFormat();
+
+let x35 = new Intl.Segmenter();
+
+let x36 = new Intl.Segmenter().segment("");
+
+let x37 = new Intl.DateTimeFormat();
+
+let x38 = new Intl.NumberFormat();
+
+let x39 = true;
+
+let x40 = new Intl.Collator();
+
+let x41 = new Intl.RelativeTimeFormat();
+
+let x42 = new Intl.PluralRules();
+
+let x43 = new Intl.Locale("en");
+
+let x45 = Promise.resolve(true);
+
+let x47 = {};
+
+let x48 = Stdlib_Lazy.make(() => true);
+
 let x1 = "hello";
 
 let x2 = 1;
@@ -41,6 +91,13 @@ let x5 = {
 
 let x12 = "test";
 
+let x44 = [
+  1,
+  2
+];
+
+let x46 = /* [] */0;
+
 export {
   x1,
   x2,
@@ -56,5 +113,31 @@ export {
   x20,
   x21,
   x22,
+  x23,
+  x24,
+  x25,
+  x26,
+  x27,
+  x28,
+  x29,
+  x30,
+  x31,
+  x32,
+  x33,
+  x34,
+  x35,
+  x36,
+  x37,
+  x38,
+  x39,
+  x40,
+  x41,
+  x42,
+  x43,
+  x44,
+  x45,
+  x46,
+  x47,
+  x48,
 }
 /* x20 Not a pure module */
diff --git a/tests/tests/src/option_wrapping_test.res b/tests/tests/src/option_wrapping_test.res
index d9d7040d84..57e03476f2 100644
--- a/tests/tests/src/option_wrapping_test.res
+++ b/tests/tests/src/option_wrapping_test.res
@@ -16,3 +16,31 @@ let x12 = Some(Nullable.Value("test"))
 let x20 = Some(Jsx.null)
 let x21 = Some(Date.make())
 let x22 = Some(/test/)
+let x23 = Some((Map.make(): Map.t<string, string>))
+let x24 = Some((Set.make(): Set.t<string>))
+let x25 = Some((WeakMap.make(): WeakMap.t<string, string>))
+let x26 = Some((WeakSet.make(): WeakSet.t<string>))
+let x27 = Some(Float32Array.fromArray([1.0]))
+let x28 = Some(Symbol.make(""))
+let x29 = Some(JsError.make(""))
+let x30 = Some(ArrayBuffer.make(0))
+let x31 = Some(ArrayBuffer.make(0)->DataView.fromBuffer)
+let x32 = Some((Map.make(): Map.t<string, string>)->Map.values)
+let x33 = Some(AsyncIterator.make(_ => AsyncIterator.value(true)->Promise.resolve))
+
+let x34 = Some(Intl.ListFormat.make())
+let x35 = Some(Intl.Segmenter.make())
+let x36 = Some(Intl.Segmenter.make()->Intl.Segmenter.segment(""))
+let x37 = Some(Intl.DateTimeFormat.make())
+let x38 = Some(Intl.NumberFormat.make())
+let x39 = Some(Intl.NumberFormat.Grouping.fromBool(true))
+let x40 = Some(Intl.Collator.make())
+let x41 = Some(Intl.RelativeTimeFormat.make())
+let x42 = Some(Intl.PluralRules.make())
+let x43 = Some(Intl.Locale.make("en"))
+
+let x44 = Some((1, 2))
+let x45 = Some(Promise.resolve(true))
+let x46 = Some(list{})
+let x47 = Some((Dict.make(): dict<string>))
+let x48 = Some(Lazy.make(_ => true))