diff --git a/src/lib/es2020.intl.d.ts b/src/lib/es2020.intl.d.ts
index c74f0566ca0..bae2790eecb 100644
--- a/src/lib/es2020.intl.d.ts
+++ b/src/lib/es2020.intl.d.ts
@@ -1,3 +1,4 @@
+/// <reference lib="es2018.intl" />
 declare namespace Intl {
 
     /**
diff --git a/tests/baselines/reference/es2020IntlAPIs.errors.txt b/tests/baselines/reference/es2020IntlAPIs.errors.txt
index cdd0156581a..de13c37357d 100644
--- a/tests/baselines/reference/es2020IntlAPIs.errors.txt
+++ b/tests/baselines/reference/es2020IntlAPIs.errors.txt
@@ -53,22 +53,22 @@ tests/cases/conformance/es2020/es2020IntlAPIs.ts(50,29): error TS2345: Argument
     new Intl.Locale(); // should error
     ~~~~~~~~~~~~~~~~~
 !!! error TS2554: Expected 1-2 arguments, but got 0.
-!!! related TS6210 /.ts/lib.es2020.intl.d.ts:335:14: An argument for 'tag' was not provided.
+!!! related TS6210 /.ts/lib.es2020.intl.d.ts:336:14: An argument for 'tag' was not provided.
     new Intl.Locale(new Intl.Locale('en-US'));
     
     new Intl.DisplayNames(); // TypeError: invalid_argument
     ~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2554: Expected 2 arguments, but got 0.
-!!! related TS6210 /.ts/lib.es2020.intl.d.ts:414:13: An argument for 'locales' was not provided.
+!!! related TS6210 /.ts/lib.es2020.intl.d.ts:415:13: An argument for 'locales' was not provided.
     new Intl.DisplayNames('en'); // TypeError: invalid_argument
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2554: Expected 2 arguments, but got 1.
-!!! related TS6210 /.ts/lib.es2020.intl.d.ts:414:39: An argument for 'options' was not provided.
+!!! related TS6210 /.ts/lib.es2020.intl.d.ts:415:39: An argument for 'options' was not provided.
     new Intl.DisplayNames('en', {}); // TypeError: invalid_argument
                                 ~~
 !!! error TS2345: Argument of type '{}' is not assignable to parameter of type 'DisplayNamesOptions'.
 !!! error TS2345:   Property 'type' is missing in type '{}' but required in type 'DisplayNamesOptions'.
-!!! related TS2728 /.ts/lib.es2020.intl.d.ts:357:9: 'type' is declared here.
+!!! related TS2728 /.ts/lib.es2020.intl.d.ts:358:9: 'type' is declared here.
     console.log((new Intl.DisplayNames(undefined, {type: 'language'})).of('en-GB')); // "British English"
     
     const localesArg = ["es-ES", new Intl.Locale("en-US")];
diff --git a/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.js b/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.js
new file mode 100644
index 00000000000..46674cdc4ee
--- /dev/null
+++ b/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.js
@@ -0,0 +1,8 @@
+//// [esnext.bigintIncludesNumberFormatPartTypes.ts]
+/// <reference lib="esnext.bigint" />
+var t: Intl.NumberFormatPartTypes
+
+
+//// [esnext.bigintIncludesNumberFormatPartTypes.js]
+/// <reference lib="esnext.bigint" />
+var t;
diff --git a/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.symbols b/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.symbols
new file mode 100644
index 00000000000..7a2e0fa6069
--- /dev/null
+++ b/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.symbols
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/esnext.bigintIncludesNumberFormatPartTypes.ts ===
+/// <reference lib="esnext.bigint" />
+var t: Intl.NumberFormatPartTypes
+>t : Symbol(t, Decl(esnext.bigintIncludesNumberFormatPartTypes.ts, 1, 3))
+>Intl : Symbol(Intl, Decl(lib.es5.d.ts, --, --), Decl(lib.es2018.intl.d.ts, --, --), Decl(lib.es2020.bigint.d.ts, --, --), Decl(lib.es2020.intl.d.ts, --, --))
+>NumberFormatPartTypes : Symbol(Intl.NumberFormatPartTypes, Decl(lib.es2018.intl.d.ts, --, --))
+
diff --git a/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.types b/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.types
new file mode 100644
index 00000000000..b1cd31d0b10
--- /dev/null
+++ b/tests/baselines/reference/esnext.bigintIncludesNumberFormatPartTypes.types
@@ -0,0 +1,6 @@
+=== tests/cases/compiler/esnext.bigintIncludesNumberFormatPartTypes.ts ===
+/// <reference lib="esnext.bigint" />
+var t: Intl.NumberFormatPartTypes
+>t : Intl.NumberFormatPartTypes
+>Intl : any
+
diff --git a/tests/cases/compiler/esnext.bigintIncludesNumberFormatPartTypes.ts b/tests/cases/compiler/esnext.bigintIncludesNumberFormatPartTypes.ts
new file mode 100644
index 00000000000..7e2aae31ea4
--- /dev/null
+++ b/tests/cases/compiler/esnext.bigintIncludesNumberFormatPartTypes.ts
@@ -0,0 +1,3 @@
+// @lib: es6
+/// <reference lib="esnext.bigint" />
+var t: Intl.NumberFormatPartTypes