functions.swift

// RUN: %target-typecheck-verify-swift -enable-objc-interop

infix operator ====
infix operator <<<<
infix operator <><>

// <rdar://problem/13782566>
// Check that func op<T>() parses without a space between the name and the
// generic parameter list.
func ====<T>(x: T, y: T) {}
func <<<<<T>(x: T, y: T) {}
func <><><T>(x: T, y: T) {}

//===--- Check that we recover when the parameter tuple is missing.

func recover_missing_parameter_tuple_1 { // expected-error {{expected '(' in argument list of function declaration}} {{39-39=()}}
}

func recover_missing_parameter_tuple_1a // expected-error {{expected '(' in argument list of function declaration}} {{40-40=()}}
{
}

func recover_missing_parameter_tuple_2<T> { // expected-error {{expected '(' in argument list of function declaration}} {{42-42=()}} expected-error {{generic parameter 'T' is not used in function signature}}
}

func recover_missing_parameter_tuple_3 -> Int { // expected-error {{expected '(' in argument list of function declaration}} {{39-39=()}}
}

func recover_missing_parameter_tuple_4<T> -> Int { // expected-error {{expected '(' in argument list of function declaration}} {{42-42=()}} expected-error {{generic parameter 'T' is not used in function signature}}
}

//===--- Check that we recover when the function return type is missing.

// Note: Don't move braces to a different line here.
func recover_missing_return_type_1() -> // expected-error {{expected type for function result}}
{
}

func recover_missing_return_type_2() -> // expected-error {{expected type for function result}} expected-error{{expected '{' in body of function declaration}}

// Note: Don't move braces to a different line here.
func recover_missing_return_type_3 -> // expected-error {{expected '(' in argument list of function declaration}} {{35-35=()}} expected-error {{expected type for function result}}
{
}

//===--- Check that we recover if ':' was used instead of '->' to specify the return type.

func recover_colon_arrow_1() : Int { } // expected-error {{expected '->' after function parameter tuple}} {{30-31=->}}
func recover_colon_arrow_2() : { }     // expected-error {{expected '->' after function parameter tuple}} {{30-31=->}} expected-error {{expected type for function result}}
func recover_colon_arrow_3 : Int { }   // expected-error {{expected '->' after function parameter tuple}} {{28-29=->}} expected-error {{expected '(' in argument list of function declaration}}
func recover_colon_arrow_4 : { }       // expected-error {{expected '->' after function parameter tuple}} {{28-29=->}} expected-error {{expected '(' in argument list of function declaration}} expected-error {{expected type for function result}}
func recover_colon_arrow_5():Int { }   // expected-error {{expected '->' after function parameter tuple}} {{29-30= -> }}
func recover_colon_arrow_6(): Int { }  // expected-error {{expected '->' after function parameter tuple}} {{29-30= ->}}
func recover_colon_arrow_7() :Int { }  // expected-error {{expected '->' after function parameter tuple}} {{30-31=-> }}

//===--- Check that we recover if the function does not have a body, but the
//===--- context requires the function to have a body.

func recover_missing_body_1() // expected-error {{expected '{' in body of function declaration}}
func recover_missing_body_2() // expected-error {{expected '{' in body of function declaration}}
    -> Int

// Ensure that we don't skip over the 'func g' over to the right paren in
// function g, while recovering from parse error in f() parameter tuple.  We
// should produce the error about missing right paren.
//
// FIXME: The errors are awful.  We should produce just the error about paren.
func f_recover_missing_tuple_paren(_ a: Int // expected-note {{to match this opening '('}} expected-error{{expected '{' in body of function declaration}} expected-error {{expected ')' in parameter}}
func g_recover_missing_tuple_paren(_ b: Int) {
}

//===--- Parse errors.

func parseError1a(_ a: ) {} // expected-error {{expected parameter type following ':'}} {{23-23= <#type#>}}

func parseError1b(_ a: // expected-error {{expected parameter type following ':'}} {{23-23= <#type#>}}
                  ) {}

func parseError2(_ a: Int, b: ) {} // expected-error {{expected parameter type following ':'}} {{30-30= <#type#>}}

func parseError3(_ a: unknown_type, b: ) {} // expected-error {{cannot find type 'unknown_type' in scope}}  expected-error {{expected parameter type following ':'}} {{39-39= <#type#>}}

func parseError4(_ a: , b: ) {} // expected-error 2{{expected parameter type following ':'}}

func parseError5(_ a: b: ) {} // expected-error {{cannot find type 'b' in scope}}  expected-error {{expected ',' separator}} {{24-24=,}} expected-error {{expected parameter name followed by ':'}}

func parseError6(_ a: unknown_type, b: ) {} // expected-error {{cannot find type 'unknown_type' in scope}}  expected-error {{expected parameter type following ':'}} {{39-39= <#type#>}}

func parseError7(_ a: Int, goo b: unknown_type) {} // expected-error {{cannot find type 'unknown_type' in scope}}

public func foo(_ a: Bool = true) -> (b: Bar, c: Bar) {} // expected-error 2{{cannot find type 'Bar' in scope}}

func parenPatternInArg((a): Int) -> Int { // expected-error {{expected parameter name followed by ':'}}
  return a  // expected-error {{cannot find 'a' in scope}}
}
parenPatternInArg(0)  // expected-error {{argument passed to call that takes no arguments}}

var nullaryClosure: (Int) -> Int = {_ in 0}
_ = nullaryClosure(0)


// rdar://16737322 - This argument is an unnamed argument that has a labeled
// tuple type as the type.  Because the labels are in the type, they are not
// parameter labels, and they are thus not in scope in the body of the function.
// expected-error@+1{{unnamed parameters must be written}} {{27-27=_: }}
func destructureArgument( (result: Int, error: Bool) ) -> Int {
  return result  // expected-error {{cannot find 'result' in scope}}
}

// The former is the same as this:
func destructureArgument2(_ a: (result: Int, error: Bool) ) -> Int {
  return result  // expected-error {{cannot find 'result' in scope}}
}


class ClassWithObjCMethod {
  @objc
  func someMethod(_ x : Int) {}
}

func testObjCMethodCurry(_ a : ClassWithObjCMethod) -> (Int) -> () {
  return a.someMethod
}

// We used to crash on this.
func rdar16786220(inout let c: Int) -> () { // expected-warning {{'let' in this position is interpreted as an argument label}} {{25-28=`let`}}
// expected-error @-1 {{'inout' before a parameter name is not allowed, place it before the parameter type instead}}{{19-24=}}{{32-32=inout }}

  c = 42
}

func multipleSpecifiers(a: inout __owned Int) {} // expected-error {{parameter may have at most one of the 'inout', 'borrowing', or 'consuming' specifiers}} {{28-34=}}

// <rdar://problem/17763388> ambiguous operator emits same candidate multiple times
infix operator !!!

func !!!<T>(lhs: Array<T>, rhs: Array<T>) -> Bool { return false }
func !!!<T>(lhs: UnsafePointer<T>, rhs: UnsafePointer<T>) -> Bool { return false }
_ = [1] !!! [1]   // unambiguously picking the array overload.


// <rdar://problem/16786168> Functions currently permit 'var inout' parameters
func inout_error(inout var x : Int) {} // expected-warning {{'var' in this position is interpreted as an argument label}} {{24-27=`var`}}
// expected-error @-1 {{'inout' before a parameter name is not allowed, place it before the parameter type instead}} {{18-23=}}{{32-32=inout }}

// Unnamed parameters require the name "_":
func unnamed(Int) { } // expected-error{{unnamed parameters must be written with the empty name '_'}}{{14-14=_: }}

func typeAttrBeforeParamDecl(@convention(c) _: () -> Void) {} // expected-error{{attribute can only be applied to types, not declarations}}

// FIXME: Bad diagnostics
func bareTypeWithAttr(@convention(c) () -> Void) {} // expected-error{{attribute can only be applied to types, not declarations}}
// expected-error @-1 {{unnamed parameters must be written with the empty name '_'}} {{38-38=_: }}

// Test fixits on curried functions.
func testCurryFixits() {
  func f1(_ x: Int)(y: Int) {} // expected-error{{cannot have more than one parameter list}}
  func f1a(_ x: Int, y: Int) {}
  func f2(_ x: Int)(y: Int)(z: Int) {} // expected-error{{cannot have more than one parameter list}}
  func f2a(_ x: Int, y: Int, z: Int) {}
  func f3(_ x: Int)() {} // expected-error{{cannot have more than one parameter list}}
  func f3a(_ x: Int) {}
  func f4()(x: Int) {} // expected-error{{cannot have more than one parameter list}}
  func f4a(_ x: Int) {}
  func f5(_ x: Int)()(y: Int) {} // expected-error{{cannot have more than one parameter list}}
  func f5a(_ x: Int, y: Int) {}
}

// Bogus diagnostic talking about a 'var' where there is none
func invalidInOutParam(x: inout XYZ) {}
// expected-error@-1{{cannot find type 'XYZ' in scope}}

// Parens around the 'inout'
func parentheticalInout(_ x: ((inout Int))) {}

var value = 0
parentheticalInout(&value)

func parentheticalInout2(_ fn: (((inout Int)), Int) -> ()) {
  var value = 0
  fn(&value, 0)
}

// https://github.com/apple/swift/issues/54133
// FIXME: None of these diagnostics is particularly good.
func bogusDestructuring() {
  struct Bar {}

  struct Foo {
    func registerCallback(_ callback: @escaping ([Bar]) -> Void) {}
    func registerCallback(_ callback: @escaping ([String: Bar]) -> Void) {}
    func registerCallback(_ callback: @escaping (Bar?) -> Void) {}
  }

  Foo().registerCallback { ([Bar]) in } // expected-warning {{unnamed parameters must be written with the empty name '_'; this is an error in the Swift 6 language mode}} {{29-29=_: }}
  Foo().registerCallback { ([String: Bar]) in }// expected-warning {{unnamed parameters must be written with the empty name '_'; this is an error in the Swift 6 language mode}} {{29-29=_: }}
  Foo().registerCallback { (Bar?) in } // expected-error {{unnamed parameters must be written with the empty name '_'}}

}