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swift-mirror/test/decl/var/usage.swift
Slava Pestov 4f1ab9d8e5 ASTScope: Directly calculate end location of GuardStmtScope and PatternEntryDeclScope
Today, the reported source range of a GuardStmtScope is just that of
the statement itself, ending after the 'else' block. Similarly, a
PatternEntryDeclScope ends immediately after the initializer
expression.

Since these scopes introduce names until the end of the parent
BraceStmt (meaning they change the insertion point), we were
relying on the addition of child scopes to extend the source
range.

While we still need the hack for extending source ranges to deal
with string interpolation, at least in the other cases we can
get rid of it.

Note that this fixes a bug where a GuardStmtScope would end
before an inactive '#if' block if the inactive '#if' block was
the last element of a BraceStmt.
2020-10-02 23:49:59 -04:00

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// RUN: %target-typecheck-verify-swift
// <rdar://problem/20872721> QoI: warn about unused variables
// <rdar://problem/15975935> warning that you can use 'let' not 'var'
// <rdar://problem/18876585> Compiler should warn me if I set a parameter as 'var' but never modify it
func basicTests() -> Int {
let x = 42 // expected-warning {{immutable value 'x' was never used; consider replacing with assignment to '_' or removing it}} {{3-8=_}}
var y = 12 // expected-warning {{variable 'y' was never mutated; consider changing to 'let' constant}} {{3-6=let}}
_ = 42 // ok
_ = 42 // ok
return y
}
func mutableParameter(_ a : Int, h : Int, var i : Int, j: Int, g: Int) -> Int { // expected-warning {{'var' in this position is interpreted as an argument label}} {{43-46=`var`}}
i += 1 // expected-error {{left side of mutating operator isn't mutable: 'i' is a 'let' constant}}
var j = j
swap(&i, &j) // expected-error {{cannot pass immutable value as inout argument: 'i' is a 'let' constant}}
return i+g
}
struct X {
func f() {}
mutating func g() {}
}
func testStruct() {
let a = X()
a.f()
var b = X()
b.g()
var c = X() // expected-warning {{variable 'c' was never mutated; consider changing to 'let' constant}} {{3-6=let}}
c.f()
}
func takeClosure(_ fn : () -> ()) {}
class TestClass {
func f() {
takeClosure { [weak self] in // self is mutable but never mutated. Ok because it is weak
self?.f()
}
}
}
enum TestEnum {
case Test(Int, Int, Int)
}
func testEnum() -> Int {
let ev = TestEnum.Test(5, 6, 7)
switch ev {
case .Test(var i, var j, var k): // expected-warning {{variable 'i' was never mutated; consider changing to 'let' constant}} {{14-17=let}}
// expected-warning@-1 {{variable 'j' was never mutated; consider changing to 'let' constant}} {{21-24=let}}
// expected-warning@-2 {{variable 'k' was never mutated; consider changing to 'let' constant}} {{28-31=let}}
return i + j + k
default:
return 0
}
}
func nestedFunction() -> Int {
var x = 42 // No warning about being never-set.
func g() {
x = 97
var q = 27 // expected-warning {{variable 'q' was never used}} {{5-10=_}}
}
g()
return x
}
func neverRead() {
var x = 42 // expected-warning {{variable 'x' was written to, but never read}}
x = 97
x = 123
}
func property() -> Int {
var p : Int { // everything ok
return 42
}
return p
}
func testInOut(_ x : inout Int) { // Ok.
}
struct TestStruct {
var property = 42
var mutatingProperty: Int {
mutating get { return 0 }
mutating set {}
}
var nonmutatingProperty: Int {
nonmutating get { return 0 }
nonmutating set {}
}
subscript(mutating index: Int) -> Int {
mutating get { return 0 }
mutating set {}
}
subscript(nonmutating index: Int) -> Int {
nonmutating get { return 0 }
nonmutating set {}
}
}
func testStructMember() -> TestStruct {
var x = TestStruct() // ok
x.property = 17
return x
}
func testMutatingProperty_get() -> TestStruct {
var x = TestStruct() // ok
_ = x.mutatingProperty
return x
}
func testMutatingProperty_set() -> TestStruct {
var x = TestStruct() // ok
x.mutatingProperty = 17
return x
}
func testNonmutatingProperty_get() -> TestStruct {
var x = TestStruct() // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
_ = x.nonmutatingProperty
return x
}
func testNonmutatingProperty_set() -> TestStruct {
var x = TestStruct() // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
x.nonmutatingProperty = 17
return x
}
func testMutatingSubscript_get() -> TestStruct {
var x = TestStruct() // ok
_ = x[mutating: 4]
return x
}
func testMutatingSubscript_set() -> TestStruct {
var x = TestStruct() // ok
x[mutating: 4] = 17
return x
}
func testNonmutatingSubscript_get() -> TestStruct {
var x = TestStruct() // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
_ = x[nonmutating: 4]
return x
}
func testNonmutatingSubscript_set() -> TestStruct {
var x = TestStruct() // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
x[nonmutating: 4] = 17
return x
}
func testSubscript() -> [Int] {
var x = [1,2,3] // ok
x[1] = 27
return x
}
func testSubscriptNeverMutated() -> [Int] {
var x = [1,2,3] // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
_ = x[1]
return x
}
func testTuple(_ x : Int) -> Int {
var x = x
var y : Int // Ok, stored by a tuple
(x, y) = (1,2)
_ = x
_ = y
return y
}
struct TestComputedPropertyStruct {
var x : Int {
get {}
nonmutating set {}
}
}
func test() {
let v = TestComputedPropertyStruct()
v.x = 42
var v2 = TestComputedPropertyStruct() // expected-warning {{variable 'v2' was never mutated; consider changing to 'let' constant}} {{3-6=let}}
v2.x = 42
}
func test4() {
// expected-warning @+1 {{variable 'dest' was never mutated; consider changing to 'let' constant}} {{3-6=let}}
var dest = UnsafeMutablePointer<Int>(bitPattern: 0)!
dest[0] = 0
}
func testTuple() {
var tup : (x:Int, y:Int) // expected-warning {{variable 'tup' was written to, but never read}}
tup.x = 1
// <rdar://problem/20927707> QoI: 'variable was never mutated' noisy when only part of a destructured tuple is mutated
var (tupA, tupB) = (1,2) // don't warn about tupB being changeable to a 'let'.
tupA += tupB
}
/// <rdar://problem/20911927> False positive in the "variable was never mutated" warning with IUO
func testForceValueExpr() {
var a: X! = nil // no warning, mutated through the !
a!.g()
}
// <rdar://problem/20894455> "variable was never mutated" diagnostic does not take #if into account
func testBuildConfigs() {
let abc = 42 // no warning.
var mut = 18 // no warning.
#if false
mut = abc // These uses prevent abc/mut from being unused/unmutated.
#endif
}
// same as above, but with a guard statement
func testGuardWithPoundIf(x: Int?) {
guard let x = x else { return }
#if false
_ = x
#endif
}
// <rdar://problem/21091625> Bogus 'never mutated' warning when protocol variable is mutated only by mutating method
protocol Fooable {
mutating func mutFoo()
func immutFoo()
var mutatingProperty: Int { mutating get mutating set }
var nonmutatingProperty: Int { nonmutating get nonmutating set }
}
func testOpenExistential(_ x: Fooable,
y: Fooable) {
var x = x
let y = y
x.mutFoo()
y.immutFoo()
}
func testOpenExistential_mutatingProperty_get(p: Fooable) {
var x = p
_ = x.mutatingProperty
}
func testOpenExistential_mutatingProperty_set(p: Fooable) {
var x = p
x.mutatingProperty = 4
}
func testOpenExistential_nonmutatingProperty_get(p: Fooable) {
var x = p // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
_ = x.nonmutatingProperty
}
func testOpenExistential_nonmutatingProperty_set(p: Fooable) {
var x = p // expected-warning {{variable 'x' was never mutated; consider changing to 'let' constant}}
x.nonmutatingProperty = 4
}
func couldThrow() throws {}
func testFixitsInStatementsWithPatterns(_ a : Int?) {
if var b = a, // expected-warning {{variable 'b' was never mutated; consider changing to 'let' constant}} {{6-9=let}}
var b2 = a { // expected-warning {{variable 'b2' was never mutated; consider changing to 'let' constant}} {{7-10=let}}
_ = b
_ = b2
}
for var b in [42] { // expected-warning {{variable 'b' was never mutated; consider removing 'var' to make it constant}} {{7-11=}}
_ = b
}
do {
try couldThrow()
} catch var err { // expected-warning {{variable 'err' was never mutated; consider changing to 'let' constant}} {{11-14=let}}
_ = err
}
switch a {
case var b: _ = b // expected-warning {{variable 'b' was never mutated; consider changing to 'let' constant}} {{10-13=let}}
}
}
// <rdar://22774938> QoI: "never used" in an "if let" should rewrite expression to use != nil
func test(_ a : Int?, b : Any) {
if true == true, let x = a { // expected-warning {{immutable value 'x' was never used; consider replacing with '_' or removing it}} {{20-25=_}}
}
if let x = a, let y = a { // expected-warning {{immutable value 'x' was never used; consider replacing with '_' or removing it}} {{6-11=_}}
_ = y
}
// Simple case, insert a comparison with nil.
if let x = a { // expected-warning {{value 'x' was defined but never used; consider replacing with boolean test}} {{6-14=}} {{15-15= != nil}}
}
// General case, need to insert parentheses.
if let x = a ?? a {} // expected-warning {{value 'x' was defined but never used; consider replacing with boolean test}} {{6-14=(}} {{20-20=) != nil}}
// Special case, we can turn this into an 'is' test.
if let x = b as? Int { // expected-warning {{value 'x' was defined but never used; consider replacing with boolean test}} {{6-14=}} {{16-19=is}}
}
// SR-1112
let xxx: Int? = 0
if let yyy = xxx { } // expected-warning{{with boolean test}} {{6-16=}} {{19-19= != nil}}
var zzz: Int? = 0
zzz = 1
if let yyy = zzz { } // expected-warning{{with boolean test}} {{6-16=}} {{19-19= != nil}}
if let yyy = zzz ?? xxx { } // expected-warning{{with boolean test}} {{6-16=(}} {{26-26=) != nil}}
}
func test2() {
let a = 4 // expected-warning {{initialization of immutable value 'a' was never used; consider replacing with assignment to '_' or removing it}} {{3-8=_}}
var ( b ) = 6 // expected-warning {{initialization of variable 'b' was never used; consider replacing with assignment to '_' or removing it}} {{3-12=_}}
var c: Int = 4 // expected-warning {{variable 'c' was never used; consider replacing with '_' or removing it}} {{7-8=_}}
let (d): Int = 9 // expected-warning {{immutable value 'd' was never used; consider replacing with '_' or removing it}} {{8-9=_}}
}
let optionalString: String? = "check"
if let string = optionalString {} // expected-warning {{value 'string' was defined but never used; consider replacing with boolean test}} {{4-17=}} {{31-31= != nil}}
let optionalAny: Any? = "check"
if let string = optionalAny as? String {} // expected-warning {{value 'string' was defined but never used; consider replacing with boolean test}} {{4-17=(}} {{39-39=) != nil}}
// Due to the complexities of global variable tracing, these will not generate warnings
let unusedVariable = ""
var unNeededVar = false
if unNeededVar {}
guard let foo = optionalAny else {}
for i in 0..<10 { // expected-warning {{immutable value 'i' was never used; consider replacing with '_' or removing it}} {{5-6=_}}
print("")
}
// Tests fix to SR-2421
func sr2421() {
let x: Int // expected-warning {{immutable value 'x' was never used; consider removing it}}
x = 42
}
// Tests fix to SR-964
func sr964() {
var noOpSetter: String {
get { return "" }
set { } // No warning
}
var suspiciousSetter: String {
get { return "" }
set {
print(suspiciousSetter) // expected-warning {{setter argument 'newValue' was never used, but the property was accessed}} expected-note {{did you mean to use 'newValue' instead of accessing the property's current value?}} {{13-29=newValue}}
}
}
struct MemberGetterStruct {
var suspiciousSetter: String {
get { return "" }
set {
print(suspiciousSetter) // expected-warning {{setter argument 'newValue' was never used, but the property was accessed}} expected-note {{did you mean to use 'newValue' instead of accessing the property's current value?}} {{15-31=newValue}}
}
}
}
class MemberGetterClass {
var suspiciousSetter: String {
get { return "" }
set {
print(suspiciousSetter) // expected-warning {{setter argument 'newValue' was never used, but the property was accessed}} expected-note {{did you mean to use 'newValue' instead of accessing the property's current value?}} {{15-31=newValue}}
}
}
}
var namedSuspiciousSetter: String {
get { return "" }
set(parameter) {
print(namedSuspiciousSetter) // expected-warning {{setter argument 'parameter' was never used, but the property was accessed}} expected-note {{did you mean to use 'parameter' instead of accessing the property's current value?}} {{13-34=parameter}}
}
}
var okSetter: String {
get { return "" }
set { print(newValue) } // No warning
}
var multiTriggerSetter: String {
get { return "" }
set {
print(multiTriggerSetter) // expected-warning {{setter argument 'newValue' was never used, but the property was accessed}} expected-note {{did you mean to use 'newValue' instead of accessing the property's current value?}} {{13-31=newValue}}
print(multiTriggerSetter)
}
}
}
struct MemberGetterExtension {}
extension MemberGetterExtension {
var suspiciousSetter: String {
get { return "" }
set {
print(suspiciousSetter) // expected-warning {{setter argument 'newValue' was never used, but the property was accessed}} expected-note {{did you mean to use 'newValue' instead of accessing the property's current value?}} {{13-29=newValue}}
}
}
}
func testLocalFunc() {
var unusedVar = 0
// expected-warning@-1 {{initialization of variable 'unusedVar' was never used; consider replacing with assignment to '_' or removing it}}
var notMutatedVar = 0
// expected-warning@-1 {{variable 'notMutatedVar' was never mutated; consider changing to 'let' constant}}
var mutatedVar = 0
// expected-warning@-1 {{variable 'mutatedVar' was written to, but never read}}
func localFunc() {
_ = notMutatedVar
mutatedVar = 1
}
}
// False positive "'var' was never mutated" warning - rdar://60563962
func testForwardReferenceCapture() {
func innerFunc() {
x = 10
}
var x: Int = 1
innerFunc()
print(x)
}
// rdar://47240768 Expand the definition of "simple" pattern to variables bound in patterns
func testVariablesBoundInPatterns() {
enum StringB {
case simple(b: Bool)
case tuple(b: (Bool, Bool))
case optional(b: Bool?)
}
// Because Swift enables all kinds of creative binding forms, make sure that
// variable patterns occuring directly under a `let` or `var` have that
// introducer stripped by the fixit. All other cases are currently too
// complicated for the VarDeclUsageChecker.
switch StringB.simple(b: true) {
case .simple(b: let b) where false: // expected-warning {{immutable value 'b' was never used; consider replacing with '_' or removing it}} {{19-24=_}}
break
case .simple(b: var b) where false: // expected-warning {{variable 'b' was never used; consider replacing with '_' or removing it}} {{19-24=_}}
break
case var .simple(b: b): // expected-warning {{variable 'b' was never used; consider replacing with '_' or removing it}} {{23-24=_}}
break
case .tuple(b: let (b1, b2)) where false:
// expected-warning@-1 {{immutable value 'b1' was never used; consider replacing with '_' or removing it}} {{23-25=_}}
// expected-warning@-2 {{immutable value 'b2' was never used; consider replacing with '_' or removing it}} {{27-29=_}}
break
case .tuple(b: (let b1, let b2)) where false:
// expected-warning@-1 {{immutable value 'b1' was never used; consider replacing with '_' or removing it}} {{19-25=_}}
// expected-warning@-2 {{immutable value 'b2' was never used; consider replacing with '_' or removing it}} {{27-33=_}}
break
case .tuple(b: (var b1, var b2)) where false:
// expected-warning@-1 {{variable 'b1' was never used; consider replacing with '_' or removing it}} {{19-25=_}}
// expected-warning@-2 {{variable 'b2' was never used; consider replacing with '_' or removing it}} {{27-33=_}}
break
case var .tuple(b: (b1, b2)) where false:
// expected-warning@-1 {{variable 'b1' was never used; consider replacing with '_' or removing it}} {{23-25=_}}
// expected-warning@-2 {{variable 'b2' was never used; consider replacing with '_' or removing it}} {{27-29=_}}
break
case .tuple(b: let b): // expected-warning {{immutable value 'b' was never used; consider replacing with '_' or removing it}} {{18-23=_}}
break
case .optional(b: let x?) where false: // expected-warning {{immutable value 'x' was never used; consider replacing with '_' or removing it}} {{25-26=_}}
break
case .optional(b: let .some(x)) where false: // expected-warning {{immutable value 'x' was never used; consider replacing with '_' or removing it}} {{31-32=_}}
break
case let .optional(b: x?): // expected-warning {{immutable value 'x' was never used; consider replacing with '_' or removing it}} {{25-26=_}}
break
case let .optional(b: .none): // expected-warning {{'let' pattern has no effect; sub-pattern didn't bind any variables}} {{8-12=}}
break
}
}