diff --git a/tests/baselines/reference/conditionalTypesASI.js b/tests/baselines/reference/conditionalTypesASI.js
new file mode 100644
index 00000000000..0399d30f153
--- /dev/null
+++ b/tests/baselines/reference/conditionalTypesASI.js
@@ -0,0 +1,18 @@
+//// [conditionalTypesASI.ts]
+// Repro from #21637
+
+interface JSONSchema4 {
+  a?: number
+  extends?: string | string[]
+}
+
+
+//// [conditionalTypesASI.js]
+// Repro from #21637
+
+
+//// [conditionalTypesASI.d.ts]
+interface JSONSchema4 {
+    a?: number;
+    extends?: string | string[];
+}
diff --git a/tests/baselines/reference/conditionalTypesASI.symbols b/tests/baselines/reference/conditionalTypesASI.symbols
new file mode 100644
index 00000000000..00480cba82b
--- /dev/null
+++ b/tests/baselines/reference/conditionalTypesASI.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/conditionalTypesASI.ts ===
+// Repro from #21637
+
+interface JSONSchema4 {
+>JSONSchema4 : Symbol(JSONSchema4, Decl(conditionalTypesASI.ts, 0, 0))
+
+  a?: number
+>a : Symbol(JSONSchema4.a, Decl(conditionalTypesASI.ts, 2, 23))
+
+  extends?: string | string[]
+>extends : Symbol(JSONSchema4.extends, Decl(conditionalTypesASI.ts, 3, 12))
+}
+
diff --git a/tests/baselines/reference/conditionalTypesASI.types b/tests/baselines/reference/conditionalTypesASI.types
new file mode 100644
index 00000000000..b0ee4502cfc
--- /dev/null
+++ b/tests/baselines/reference/conditionalTypesASI.types
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/conditionalTypesASI.ts ===
+// Repro from #21637
+
+interface JSONSchema4 {
+>JSONSchema4 : JSONSchema4
+
+  a?: number
+>a : number
+
+  extends?: string | string[]
+>extends : string | string[]
+}
+