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// RUN: %target-swift-frontend -emit-sil -disable-objc-attr-requires-foundation-module -verify %s
// High-level tests that DI rejects passing let constants to
// mutating witness methods
// Mark: General Definitions
protocol TestProtocol {
var foo: Int { get set }
}
struct TestStruct: TestProtocol {
var foo: Int
}
// Mark: - Case1: Illegally mutating let property of class in initializer
class TestClass {
let testObject: TestProtocol // expected-note {{change 'let' to 'var' to make it mutable}}
init() {
testObject = TestStruct(foo: 42)
testObject.foo = 666 // expected-error {{cannot mutate property 'foo' of immutable value 'self.testObject'}}
}
}
// Mark: - Case2: Illegally mutating global let constant
let testObject: TestProtocol // expected-note {{change 'let' to 'var' to make it mutable}}
testObject = TestStruct(foo: 42)
testObject.foo = 666 // expected-error {{cannot mutate property 'foo' of immutable value 'testObject'}}
extension TestProtocol {
mutating func messThingsUp() {
foo = 666
}
mutating func messThingsUpAndThenThrow() throws {
foo = 616
}
}
// Mark: - Case3: Illegally mutating let constant in a function scope
let testObject2: TestProtocol // expected-note 2 {{change 'let' to 'var' to make it mutable}}
testObject2 = TestStruct(foo: 42)
testObject2.messThingsUp() // expected-error {{mutating method 'messThingsUp' may not be used on immutable value 'testObject2'}}
try! testObject2.messThingsUpAndThenThrow() // expected-error {{mutating method 'messThingsUpAndThenThrow' may not be used on immutable value 'testObject2'}}
func testFunc() {
let testObject: TestProtocol // expected-note {{change 'let' to 'var' to make it mutable}}
testObject = TestStruct(foo: 42)
testObject.foo = 666 // expected-error {{cannot mutate property 'foo' of immutable value 'testObject'}}
}
// Mark: - Case4: Illegally passing a let constants property as an inout parameter
let testObject3: TestProtocol // expected-note {{change 'let' to 'var' to make it mutable}}
testObject3 = TestStruct(foo: 42)
func mutateThis(mutatee: inout Int) {
mutatee = 666
}
mutateThis(mutatee: &testObject3.foo) // expected-error {{cannot mutate property 'foo' of immutable value 'testObject3'}}
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