diff --git a/src/lib/es2018.intl.d.ts b/src/lib/es2018.intl.d.ts
index 9fe8f63c28620..9395f43903554 100644
--- a/src/lib/es2018.intl.d.ts
+++ b/src/lib/es2018.intl.d.ts
@@ -37,9 +37,12 @@ declare namespace Intl {
         supportedLocalesOf(locales: string | string[], options?: { localeMatcher?: "lookup" | "best fit" }): string[];
     };
 
+    // We can only have one definition for 'type' in TypeScript, and so you can learn where the keys come from here:
     type ES2018NumberFormatPartType = "literal" | "nan" | "infinity" | "percent" | "integer" | "group" | "decimal" | "fraction" | "plusSign" | "minusSign" | "percentSign" | "currency" | "code" | "symbol" | "name";
+    type ES2020NumberFormatPartType = "compact" | "exponentInteger" | "exponentMinusSign" | "exponentSeparator" | "unit" | "unknown";
+
     interface NumberFormatPart {
-        type: ES2018NumberFormatPartType;
+        type: ES2018NumberFormatPartType | ES2020NumberFormatPartType;
         value: string;
     }
 
diff --git a/src/lib/es2020.intl.d.ts b/src/lib/es2020.intl.d.ts
index 3a5c4958aa5e0..f351ee3c0cee6 100644
--- a/src/lib/es2020.intl.d.ts
+++ b/src/lib/es2020.intl.d.ts
@@ -197,16 +197,11 @@ declare namespace Intl {
         ): UnicodeBCP47LocaleIdentifier[];
     };
 
-    type ES2020NumberFormatPartType = ES2018NumberFormatPartType | "compact" | "exponentInteger" | "exponentMinusSign" | "exponentSeparator" | "unit" | "unknown";
-    interface NumberFormatPart {
-        type: ES2020NumberFormatPartType
-    }
-
     interface NumberFormatOptions {
         compactDisplay?: "short" | "long" | undefined;
         notation?: "standard" | "scientific" | "engineering" | "compact" | undefined;
         signDisplay?: "auto" | "never" | "always" | undefined;
-        unit?: NumberFormatUnit | undefined;
+        unit?: string | undefined;
         unitDisplay?: "short" | "long" | "narrow" | undefined;
     }
 
@@ -214,7 +209,7 @@ declare namespace Intl {
         compactDisplay?: "short" | "long";
         notation?: "standard" | "scientific" | "engineering" | "compact";
         signDisplay?: "auto" | "never" | "always";
-        unit?: NumberFormatUnit;
+        unit?: string;
         unitDisplay?: "short" | "long" | "narrow";
     }
 
diff --git a/tests/baselines/reference/libCompileChecks.js b/tests/baselines/reference/libCompileChecks.js
new file mode 100644
index 0000000000000..d36f70bb440d0
--- /dev/null
+++ b/tests/baselines/reference/libCompileChecks.js
@@ -0,0 +1,7 @@
+//// [libCompileChecks.ts]
+// This test is effectively the 'lib check' for all our .d.ts files because we use skipLibCheck
+// as false everywhere.
+
+//// [libCompileChecks.js]
+// This test is effectively the 'lib check' for all our .d.ts files because we use skipLibCheck
+// as false everywhere.
diff --git a/tests/baselines/reference/libCompileChecks.symbols b/tests/baselines/reference/libCompileChecks.symbols
new file mode 100644
index 0000000000000..2bed52247c080
--- /dev/null
+++ b/tests/baselines/reference/libCompileChecks.symbols
@@ -0,0 +1,4 @@
+=== tests/cases/compiler/libCompileChecks.ts ===
+// This test is effectively the 'lib check' for all our .d.ts files because we use skipLibCheck
+No type information for this code.// as false everywhere.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/libCompileChecks.types b/tests/baselines/reference/libCompileChecks.types
new file mode 100644
index 0000000000000..2bed52247c080
--- /dev/null
+++ b/tests/baselines/reference/libCompileChecks.types
@@ -0,0 +1,4 @@
+=== tests/cases/compiler/libCompileChecks.ts ===
+// This test is effectively the 'lib check' for all our .d.ts files because we use skipLibCheck
+No type information for this code.// as false everywhere.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/cases/compiler/libCompileChecks.ts b/tests/cases/compiler/libCompileChecks.ts
new file mode 100644
index 0000000000000..36f17f009e0a3
--- /dev/null
+++ b/tests/cases/compiler/libCompileChecks.ts
@@ -0,0 +1,7 @@
+// @lib: esnext, dom
+// @target: esnext
+// @skipLibCheck: false
+// @skipDefaultLibCheck: false
+
+// This test is effectively the 'lib check' for all our .d.ts files because we use skipLibCheck
+// as false everywhere.
\ No newline at end of file