Fix issue with custom types shadowing basic types

[dedalusj]

Fix an issue when a custom type has a name matching one of the basic type and the generated mock method has a var name shadowing the type of the basic type, e.g. the following interface

package something

import (
	"gopkg.in/guregu/null.v4"
)

type NullString interface {
	NullString(string, null.String)
}

generates

// ...

type NullStringMock struct {
	// NullStringFunc mocks the NullString method.
	NullStringFunc func(s string, string null.String)
       
       // ...
}

// NullString calls NullStringFunc.
func (mock *NullStringMock) NullString(s string, string null.String) {
	if mock. NullStringFunc == nil {
		panic("NullStringMock.NullStringFunc: method is nil but NullString.NullString was just called")
	}
	callInfo := struct {
		S      string
		String null.String
	}{
		S:      s,
		String: string,
	}
	// ...
}

where the second argument shadow the builtin type string causing a compilation error.

[sudo-suhas]

Could you convert this to a test case under TestMockGolden?

You can generate the golden file using go test -v -run '^<Test-Name>$' github.com/matryer/moq/pkg/moq -update

[dedalusj]

Done. Let me know if it looks OK.

[sudo-suhas]

Thank you very much @dedalusj for the fix! Changes have been released in moq v0.2.5 🎉