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Issue Description:

The following (minimized) example fails to compile in the new 5.2 release, but worked fine in Swift 5.1:

@dynamicCallable
@dynamicMemberLookup
public struct Foo {
    subscript(dynamicMember memberName: String) -> Foo {
        get { return self }
        set { self = newValue }
    }

    func think() -> [Foo] { [self] }
    
    @discardableResult
    func dynamicallyCall(
      withKeywordArguments args:
        KeyValuePairs<String, Int> = [:]
    ) -> Foo {
        return self
    }
}


var f = Foo()
print(f.think(arg: 1)) // error here

In Swift 5.1, this would do a dynamic member lookup to find think, then call it dynamically with [arg:1]. In Swift 5.2, this finds the non-dynamic think method and tries to call that. It doesn't work because that method has no arguments.

The errors output are as follows:

dynamic-error.swift:22:20: error: argument passed to call that takes no arguments
print(f.think(arg: 1))
                   ^

The fact that this used to work is definitely a little odd, but it makes usecases like PythonKit much harder to use. In the code this example came from, Foo was PythonObject and think was a method called filter.

The workaround is to replace the