fix(types): improve type of unref()

fix #3954

Author: yyx990803

packages/reactivity/src/ref.ts

@@ -85,7 +85,7 @@ export function triggerRef(ref: Ref) {
   trigger(toRaw(ref), TriggerOpTypes.SET, 'value', __DEV__ ? ref.value : void 0)
 }
 
-export function unref<T>(ref: T): T extends Ref<infer V> ? V : T {
+export function unref<T>(ref: T | Ref<T>): T {
   return isRef(ref) ? (ref.value as any) : ref
 }
 

test-dts/ref.test-d.ts

@@ -203,3 +203,10 @@ switch (data.state.value) {
     data.state.value = 'state1'
     break
 }
+
+// #3954
+function testUnrefGenerics<T>(p: T | Ref<T>) {
+  expectType<T>(unref(p))
+}
+
+testUnrefGenerics(1)