diff --git a/tsc/internal/checker/checker.go b/tsc/internal/checker/checker.go
index 415c8ecdf73f2..1508cd7f6a726 100644
--- a/tsc/internal/checker/checker.go
+++ b/tsc/internal/checker/checker.go
@@ -24268,6 +24268,7 @@ func (c *Checker) getInferTypeParameters(node *ast.Node) []*Type {
 			result = append(result, c.getDeclaredTypeOfSymbol(symbol))
 		}
 	}
+	slices.SortFunc(result, CompareTypes)
 	return result
 }
 
diff --git a/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.js b/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.js
new file mode 100644
index 0000000000000..b952fd27365b5
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.js
@@ -0,0 +1,54 @@
+//// [tests/cases/compiler/stableTypeMapperOrdering.ts] ////
+
+//// [stableTypeMapperOrdering.ts]
+// https://github.com/microsoft/TypeScript/issues/64589
+
+interface Endpoint<Name, Params, Middleware, Services> {
+  readonly name: Name;
+  readonly params: Params;
+  readonly middleware: Middleware;
+  readonly services: Services;
+}
+
+type Same<A, R> = R;
+
+type AddMiddleware<E, I> =
+  E extends Endpoint<infer N, infer P, infer M, infer S>
+    ? Endpoint<N, P, M | I, Same<I, S>>
+    : never;
+
+interface Group<Endpoints> {
+  add<N extends string, P = never>(
+    name: N,
+    params?: P,
+  ): Group<Endpoints | Endpoint<N, P, never, never>>;
+  middleware<I>(id: I): Group<AddMiddleware<Endpoints, I>>;
+}
+
+declare const group: Group<never>;
+
+export const result = group.add("a", { id: "" }).add("c").middleware("m" as const);
+
+
+//// [stableTypeMapperOrdering.js]
+// https://github.com/microsoft/TypeScript/issues/64589
+export const result = group.add("a", { id: "" }).add("c").middleware("m");
+
+
+//// [stableTypeMapperOrdering.d.ts]
+interface Endpoint<Name, Params, Middleware, Services> {
+    readonly name: Name;
+    readonly params: Params;
+    readonly middleware: Middleware;
+    readonly services: Services;
+}
+type Same<A, R> = R;
+type AddMiddleware<E, I> = E extends Endpoint<infer N, infer P, infer M, infer S> ? Endpoint<N, P, M | I, Same<I, S>> : never;
+interface Group<Endpoints> {
+    add<N extends string, P = never>(name: N, params?: P): Group<Endpoints | Endpoint<N, P, never, never>>;
+    middleware<I>(id: I): Group<AddMiddleware<Endpoints, I>>;
+}
+export declare const result: Group<Endpoint<"a", {
+    id: string;
+}, "m", never> | Endpoint<"c", never, "m", never>>;
+export {};
diff --git a/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.symbols b/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.symbols
new file mode 100644
index 0000000000000..3a60fd1d4ce2a
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.symbols
@@ -0,0 +1,111 @@
+//// [tests/cases/compiler/stableTypeMapperOrdering.ts] ////
+
+=== stableTypeMapperOrdering.ts ===
+// https://github.com/microsoft/TypeScript/issues/64589
+
+interface Endpoint<Name, Params, Middleware, Services> {
+>Endpoint : Symbol(Endpoint, Decl(stableTypeMapperOrdering.ts, 0, 0))
+>Name : Symbol(Name, Decl(stableTypeMapperOrdering.ts, 2, 19))
+>Params : Symbol(Params, Decl(stableTypeMapperOrdering.ts, 2, 24))
+>Middleware : Symbol(Middleware, Decl(stableTypeMapperOrdering.ts, 2, 32))
+>Services : Symbol(Services, Decl(stableTypeMapperOrdering.ts, 2, 44))
+
+  readonly name: Name;
+>name : Symbol(Endpoint.name, Decl(stableTypeMapperOrdering.ts, 2, 56))
+>Name : Symbol(Name, Decl(stableTypeMapperOrdering.ts, 2, 19))
+
+  readonly params: Params;
+>params : Symbol(Endpoint.params, Decl(stableTypeMapperOrdering.ts, 3, 22))
+>Params : Symbol(Params, Decl(stableTypeMapperOrdering.ts, 2, 24))
+
+  readonly middleware: Middleware;
+>middleware : Symbol(Endpoint.middleware, Decl(stableTypeMapperOrdering.ts, 4, 26))
+>Middleware : Symbol(Middleware, Decl(stableTypeMapperOrdering.ts, 2, 32))
+
+  readonly services: Services;
+>services : Symbol(Endpoint.services, Decl(stableTypeMapperOrdering.ts, 5, 34))
+>Services : Symbol(Services, Decl(stableTypeMapperOrdering.ts, 2, 44))
+}
+
+type Same<A, R> = R;
+>Same : Symbol(Same, Decl(stableTypeMapperOrdering.ts, 7, 1))
+>A : Symbol(A, Decl(stableTypeMapperOrdering.ts, 9, 10))
+>R : Symbol(R, Decl(stableTypeMapperOrdering.ts, 9, 12))
+>R : Symbol(R, Decl(stableTypeMapperOrdering.ts, 9, 12))
+
+type AddMiddleware<E, I> =
+>AddMiddleware : Symbol(AddMiddleware, Decl(stableTypeMapperOrdering.ts, 9, 20))
+>E : Symbol(E, Decl(stableTypeMapperOrdering.ts, 11, 19))
+>I : Symbol(I, Decl(stableTypeMapperOrdering.ts, 11, 21))
+
+  E extends Endpoint<infer N, infer P, infer M, infer S>
+>E : Symbol(E, Decl(stableTypeMapperOrdering.ts, 11, 19))
+>Endpoint : Symbol(Endpoint, Decl(stableTypeMapperOrdering.ts, 0, 0))
+>N : Symbol(N, Decl(stableTypeMapperOrdering.ts, 12, 26))
+>P : Symbol(P, Decl(stableTypeMapperOrdering.ts, 12, 35))
+>M : Symbol(M, Decl(stableTypeMapperOrdering.ts, 12, 44))
+>S : Symbol(S, Decl(stableTypeMapperOrdering.ts, 12, 53))
+
+    ? Endpoint<N, P, M | I, Same<I, S>>
+>Endpoint : Symbol(Endpoint, Decl(stableTypeMapperOrdering.ts, 0, 0))
+>N : Symbol(N, Decl(stableTypeMapperOrdering.ts, 12, 26))
+>P : Symbol(P, Decl(stableTypeMapperOrdering.ts, 12, 35))
+>M : Symbol(M, Decl(stableTypeMapperOrdering.ts, 12, 44))
+>I : Symbol(I, Decl(stableTypeMapperOrdering.ts, 11, 21))
+>Same : Symbol(Same, Decl(stableTypeMapperOrdering.ts, 7, 1))
+>I : Symbol(I, Decl(stableTypeMapperOrdering.ts, 11, 21))
+>S : Symbol(S, Decl(stableTypeMapperOrdering.ts, 12, 53))
+
+    : never;
+
+interface Group<Endpoints> {
+>Group : Symbol(Group, Decl(stableTypeMapperOrdering.ts, 14, 12))
+>Endpoints : Symbol(Endpoints, Decl(stableTypeMapperOrdering.ts, 16, 16))
+
+  add<N extends string, P = never>(
+>add : Symbol(Group.add, Decl(stableTypeMapperOrdering.ts, 16, 28))
+>N : Symbol(N, Decl(stableTypeMapperOrdering.ts, 17, 6))
+>P : Symbol(P, Decl(stableTypeMapperOrdering.ts, 17, 23))
+
+    name: N,
+>name : Symbol(name, Decl(stableTypeMapperOrdering.ts, 17, 35))
+>N : Symbol(N, Decl(stableTypeMapperOrdering.ts, 17, 6))
+
+    params?: P,
+>params : Symbol(params, Decl(stableTypeMapperOrdering.ts, 18, 12))
+>P : Symbol(P, Decl(stableTypeMapperOrdering.ts, 17, 23))
+
+  ): Group<Endpoints | Endpoint<N, P, never, never>>;
+>Group : Symbol(Group, Decl(stableTypeMapperOrdering.ts, 14, 12))
+>Endpoints : Symbol(Endpoints, Decl(stableTypeMapperOrdering.ts, 16, 16))
+>Endpoint : Symbol(Endpoint, Decl(stableTypeMapperOrdering.ts, 0, 0))
+>N : Symbol(N, Decl(stableTypeMapperOrdering.ts, 17, 6))
+>P : Symbol(P, Decl(stableTypeMapperOrdering.ts, 17, 23))
+
+  middleware<I>(id: I): Group<AddMiddleware<Endpoints, I>>;
+>middleware : Symbol(Group.middleware, Decl(stableTypeMapperOrdering.ts, 20, 53))
+>I : Symbol(I, Decl(stableTypeMapperOrdering.ts, 21, 13))
+>id : Symbol(id, Decl(stableTypeMapperOrdering.ts, 21, 16))
+>I : Symbol(I, Decl(stableTypeMapperOrdering.ts, 21, 13))
+>Group : Symbol(Group, Decl(stableTypeMapperOrdering.ts, 14, 12))
+>AddMiddleware : Symbol(AddMiddleware, Decl(stableTypeMapperOrdering.ts, 9, 20))
+>Endpoints : Symbol(Endpoints, Decl(stableTypeMapperOrdering.ts, 16, 16))
+>I : Symbol(I, Decl(stableTypeMapperOrdering.ts, 21, 13))
+}
+
+declare const group: Group<never>;
+>group : Symbol(group, Decl(stableTypeMapperOrdering.ts, 24, 13))
+>Group : Symbol(Group, Decl(stableTypeMapperOrdering.ts, 14, 12))
+
+export const result = group.add("a", { id: "" }).add("c").middleware("m" as const);
+>result : Symbol(result, Decl(stableTypeMapperOrdering.ts, 26, 12))
+>group.add("a", { id: "" }).add("c").middleware : Symbol(Group.middleware, Decl(stableTypeMapperOrdering.ts, 20, 53))
+>group.add("a", { id: "" }).add : Symbol(Group.add, Decl(stableTypeMapperOrdering.ts, 16, 28))
+>group.add : Symbol(Group.add, Decl(stableTypeMapperOrdering.ts, 16, 28))
+>group : Symbol(group, Decl(stableTypeMapperOrdering.ts, 24, 13))
+>add : Symbol(Group.add, Decl(stableTypeMapperOrdering.ts, 16, 28))
+>id : Symbol(id, Decl(stableTypeMapperOrdering.ts, 26, 38))
+>add : Symbol(Group.add, Decl(stableTypeMapperOrdering.ts, 16, 28))
+>middleware : Symbol(Group.middleware, Decl(stableTypeMapperOrdering.ts, 20, 53))
+>const : Symbol(const)
+
diff --git a/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.types b/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.types
new file mode 100644
index 0000000000000..1ced1bacefd75
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/stableTypeMapperOrdering.types
@@ -0,0 +1,68 @@
+//// [tests/cases/compiler/stableTypeMapperOrdering.ts] ////
+
+=== stableTypeMapperOrdering.ts ===
+// https://github.com/microsoft/TypeScript/issues/64589
+
+interface Endpoint<Name, Params, Middleware, Services> {
+  readonly name: Name;
+>name : Name
+
+  readonly params: Params;
+>params : Params
+
+  readonly middleware: Middleware;
+>middleware : Middleware
+
+  readonly services: Services;
+>services : Services
+}
+
+type Same<A, R> = R;
+>Same : R
+
+type AddMiddleware<E, I> =
+>AddMiddleware : AddMiddleware<E, I>
+
+  E extends Endpoint<infer N, infer P, infer M, infer S>
+    ? Endpoint<N, P, M | I, Same<I, S>>
+    : never;
+
+interface Group<Endpoints> {
+  add<N extends string, P = never>(
+>add : <N extends string, P = never>(name: N, params?: P) => Group<Endpoints | Endpoint<N, P, never, never>>
+
+    name: N,
+>name : N
+
+    params?: P,
+>params : P | undefined
+
+  ): Group<Endpoints | Endpoint<N, P, never, never>>;
+  middleware<I>(id: I): Group<AddMiddleware<Endpoints, I>>;
+>middleware : <I>(id: I) => Group<AddMiddleware<Endpoints, I>>
+>id : I
+}
+
+declare const group: Group<never>;
+>group : Group<never>
+
+export const result = group.add("a", { id: "" }).add("c").middleware("m" as const);
+>result : Group<Endpoint<"a", { id: string; }, "m", never> | Endpoint<"c", never, "m", never>>
+>group.add("a", { id: "" }).add("c").middleware("m" as const) : Group<Endpoint<"a", { id: string; }, "m", never> | Endpoint<"c", never, "m", never>>
+>group.add("a", { id: "" }).add("c").middleware : <I>(id: I) => Group<Endpoint<"a", { id: string; }, I, never> | Endpoint<"c", never, I, never>>
+>group.add("a", { id: "" }).add("c") : Group<Endpoint<"a", { id: string; }, never, never> | Endpoint<"c", never, never, never>>
+>group.add("a", { id: "" }).add : <N extends string, P = never>(name: N, params?: P | undefined) => Group<Endpoint<"a", { id: string; }, never, never> | Endpoint<N, P, never, never>>
+>group.add("a", { id: "" }) : Group<Endpoint<"a", { id: string; }, never, never>>
+>group.add : <N extends string, P = never>(name: N, params?: P | undefined) => Group<Endpoint<N, P, never, never>>
+>group : Group<never>
+>add : <N extends string, P = never>(name: N, params?: P | undefined) => Group<Endpoint<N, P, never, never>>
+>"a" : "a"
+>{ id: "" } : { id: string; }
+>id : string
+>"" : ""
+>add : <N extends string, P = never>(name: N, params?: P | undefined) => Group<Endpoint<"a", { id: string; }, never, never> | Endpoint<N, P, never, never>>
+>"c" : "c"
+>middleware : <I>(id: I) => Group<Endpoint<"a", { id: string; }, I, never> | Endpoint<"c", never, I, never>>
+>"m" as const : "m"
+>"m" : "m"
+
diff --git a/tsc/testdata/tests/cases/compiler/stableTypeMapperOrdering.ts b/tsc/testdata/tests/cases/compiler/stableTypeMapperOrdering.ts
new file mode 100644
index 0000000000000..624003b554aa0
--- /dev/null
+++ b/tsc/testdata/tests/cases/compiler/stableTypeMapperOrdering.ts
@@ -0,0 +1,29 @@
+// @declaration: true
+
+// https://github.com/microsoft/TypeScript/issues/64589
+
+interface Endpoint<Name, Params, Middleware, Services> {
+  readonly name: Name;
+  readonly params: Params;
+  readonly middleware: Middleware;
+  readonly services: Services;
+}
+
+type Same<A, R> = R;
+
+type AddMiddleware<E, I> =
+  E extends Endpoint<infer N, infer P, infer M, infer S>
+    ? Endpoint<N, P, M | I, Same<I, S>>
+    : never;
+
+interface Group<Endpoints> {
+  add<N extends string, P = never>(
+    name: N,
+    params?: P,
+  ): Group<Endpoints | Endpoint<N, P, never, never>>;
+  middleware<I>(id: I): Group<AddMiddleware<Endpoints, I>>;
+}
+
+declare const group: Group<never>;
+
+export const result = group.add("a", { id: "" }).add("c").middleware("m" as const);