错误信息是正确的。Model 指的是函数参数的值，你应该使用 typeof 来指代它的类型。请参阅 https://www.typescriptlang.org/docs/handbook/2/typeof-types.html 。

错误信息是正确的。Model 指的是函数参数的值，你应该使用 typeof 来指代它的类型。参见 https://www.typescriptlang.org/docs/handbook/2/typeof-types.html 。
我知道 typeof 是“正确的语法”，但如果我按照那样修改，Parameter Decorator 将无法获取发出的类：

const register: MethodDecorator = () => { }

const validate: ParameterDecorator = () => { }

function mixin<T>(Model: new (...data: any[]) => T) {
    class Trait {
        @register
-        method(@validate input: Model) { }
+        method(@validate input: typeof Model) { }
    }
    return Trait;
}

class TestModel {
    id = 0
}

class TestController extends mixin(TestModel) { }

function mixin(Model) {
    var _a;
    class Trait {
        method(input) { }
    }
    __decorate([
        register,
        __param(0, validate),
        __metadata("design:type", Function),
-        __metadata("design:paramtypes", [typeof (_a = typeof Model !== "undefined" && Model) === "function" ? _a : Object]),
+        __metadata("design:paramtypes", [Object]),
        __metadata("design:returntype", void 0)
    ], Trait.prototype, "method", null);
    return Trait;
}

我认为这个解决方法应该可行：

function mixin<T>(Model: new (...data: any[]) => T) {
+    type Model = typeof Model;
    
    class Trait {
        @register
        method(@validate input: Model) { }
    }
    return Trait;
}

感谢你的hack代码，但我想知道class语法既是类型又是值，为什么在mixins中我要使用typeof?

如果同时使用类的类型和值，您的hack代码在我的VS Code 1.71.0中显示类型错误：

- const register: MethodDecorator = () => { }
+ const register: (Model: new (...data: any[]) => any) => MethodDecorator =
    () => () => { }

const validate: ParameterDecorator = () => { }

function mixin<T>(Model: new (...data: any[]) => T) {
+    type Model = typeof Model;

    class Trait {
-        @register
+        @register(Model)
        method(@validate input: Model) { }
    }
    return Trait;
}

class TestModel {
    id = 0
}

class TestController extends mixin(TestModel) { }

ts[2502] Model is referenced directly or indirectly in its own type annotation.

但是，tsc 在 typescript@4.8.3 中编译时与相同的 node_modules 一起工作正常...
TS playground 和 GitPod 的VS Code 1.69.2也运行正常...

@TechQuery
why should I use typeof in mixins?
A class declaration does create value and type entities but a variable only create the value one. In your case Model is just a variable refers to the class, so it doesn't create a type entity.
If I use both type & value of classes, your hack code shows a type error in my VS Code 1.71.0
I believe this is a bug, which is similar to #50191 and #50161 . I have reported it in #50795 .

最小复制品。

const A: new() => any = class B {}
function validate(...a: any[]) {}
class B {
    @validate test(a: typeof A) {}
}

编译为

看起来 typeof Expr 的行为在装饰器元数据中没有得到妥善处理。

感谢你的解释和问题报告。
当我再次打开GitPod的VS Code时，出现了相同的错误提示...
就像#50161所说的：有时候...