same name enum type in inner scope can produce incorrect diagnostic

[nishanths]

Input like this currently produce an incorrect diagnostic.

package example

type T int

const (
	A T = iota
	B
)

func f() {
	type T int

	const (
		C T = iota
		D
	)
	
	var v T
	switch v {
	case C, D:
	}
}

The incorrect diagnostic is:

missing cases in switch of type T: A, B

Background

The analyzer only supports enum types that are at the package level. To lookup an enum type, it looks up a map using a string key equal to the enum type name. If an inner scope has a type of the same name, like in this example, it results in an incorrect diagnostic.

Next steps

It may be best to address this together with #11.