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// RUN: %target-typecheck-verify-swift
var t = true
var f = false
func markUsed<T>(_ t: T) {}
markUsed(t != nil) // expected-warning {{comparing non-optional value of type 'Bool' to 'nil' always returns true}}
markUsed(f != nil) // expected-warning {{comparing non-optional value of type 'Bool' to 'nil' always returns true}}
markUsed(t != Optional.none) // expected-warning {{comparing non-optional value of type 'Bool' to 'Optional.none' always returns true}}
markUsed(f != Optional.none) // expected-warning {{comparing non-optional value of type 'Bool' to 'Optional.none' always returns true}}
class C : Equatable {}
func == (lhs: C, rhs: C) -> Bool {
return true
}
func test(_ c: C) {
if c == nil {} // expected-warning {{comparing non-optional value of type 'C' to 'nil' always returns false}}
if c == .none {} // expected-warning {{comparing non-optional value of type 'C' to 'Optional.none' always returns false}}
if c == Optional.none {} // expected-warning {{comparing non-optional value of type 'C' to 'Optional.none' always returns false}}
if c == C?.none {} // expected-warning {{comparing non-optional value of type 'C' to 'Optional.none' always returns false}}
}
class D {}
var d = D()
var dopt: D? = nil
var diuopt: D! = nil
func produceD() -> D! { D() }
_ = d! // expected-error {{cannot force unwrap value of non-optional type 'D'}}
_ = dopt == nil
_ = diuopt == nil
_ = diuopt is ExpressibleByNilLiteral // expected-warning {{'is' test is always true}}
_ = produceD() is ExpressibleByNilLiteral // expected-warning {{'is' test is always true}}
enum E {
case none
}
func test(_ e: E) {
_ = e == .none
_ = e == E.none
_ = e == Optional.none // expected-warning {{comparing non-optional value of type 'E' to 'Optional.none' always returns false}}
_ = e == E?.none // expected-warning {{comparing non-optional value of type 'E' to 'Optional.none' always returns false}}
}
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