V := test.T
		T := test.V
		want := false
		if _, ok := T.Underlying().(*Interface); (ok || Implements(T, V)) && T != Bad {
			want = true
		}
		if got := AssertableTo(V, T); got != want {
			t.Errorf("AssertableTo(%s, %s) = %t, want %t", V, T, got, want)
		}
	}
}

func TestMissingMethodAlternative(t *testing.T) {
	const src = `
package p
type T interface {
	m()
}

		V := test.T
		T := test.V
		want := false
		if _, ok := T.Underlying().(*Interface); (ok || Implements(T, V)) && T != Bad {
			want = true
		}
		if got := AssertableTo(V, T); got != want {
			t.Errorf("AssertableTo(%s, %s) = %t, want %t", V, T, got, want)
		}
	}
}

func TestMissingMethodAlternative(t *testing.T) {
	const src = `
package p
type T interface {
	m()
}

	}
	return x
}

// typeAssertion checks x.(T). The type of x must be an interface.
func (check *Checker) typeAssertion(e ast.Expr, x *operand, T Type, typeSwitch bool) {
	var cause string
	if check.assertableTo(x.typ, T, &cause) {
		return // success
	}

	if typeSwitch {
		check.errorf(e, ImpossibleAssert, "impossible type switch case: %s\n\t%s cannot have dynamic type %s %s", e, x, T, cause)
		return
	}

	}
	return x
}

// typeAssertion checks x.(T). The type of x must be an interface.
func (check *Checker) typeAssertion(e syntax.Expr, x *operand, T Type, typeSwitch bool) {
	var cause string
	if check.assertableTo(x.typ, T, &cause) {
		return // success
	}

	if typeSwitch {
		check.errorf(e, ImpossibleAssert, "impossible type switch case: %s\n\t%s cannot have dynamic type %s %s", e, x, T, cause)
		return
	}