c_function_pointers.swift

// RUN: %target-swift-frontend -typecheck -verify -module-name main %s
func global()->Int{return0}

structS{
staticfunc staticMethod()->Int{return0}
}

classC{
staticfunc staticMethod()->Int{return0}
classfunc classMethod()->Int{return0}
}

iftrue{
func local()->Int{return0}

leta:@convention(c)()->Int= global
let _:@convention(c)()->Int= main.global
let _:@convention(c)()->Int={0}
let _:@convention(c)()->Int= local

 // Can't convert a closure value to a C function pointer
letglobal2= global
let _:@convention(c)()->Int= global2 // expected-error{{can only be formed from a reference to a 'func' or a literal closure}}
letglobalBlock:@convention(block)()->Int= global
let _:@convention(c)()->Int= globalBlock // expected-error{{can only be formed from a reference to a 'func' or a literal closure}}

 // Can convert a function pointer to a block or closure, or assign to another
 // C function pointer
let _:@convention(c)()->Int= a
let _:@convention(block)()->Int= a
let _:()->Int= a

 // Can't convert a C function pointer from a method.
 // TODO: Could handle static methods.
let _:@convention(c)()->Int=S.staticMethod // expected-error{{}}
let _:@convention(c)()->Int=C.staticMethod // expected-error{{}}
let _:@convention(c)()->Int=C.classMethod // expected-error{{}}

 // <rdar://problem/22181714> Crash when typing "signal"
letiuo_global:(()->Int)!= global
let _:(@convention(c)()->Int)!= iuo_global // expected-error{{a C function pointer can only be formed from a reference to a 'func' or a literal closure}}

func handler(_ callback:(@convention(c)()->Int)!){}
handler(iuo_global) // expected-error{{a C function pointer can only be formed from a reference to a 'func' or a literal closure}}
}

func genericFunc<T>(_ t:T)->T{return t }

letf:@convention(c)(Int)->Int= genericFunc // expected-error{{cannot be formed from a reference to a generic function}}

func ct1()->(){print("")}

letct1ref0:@convention(c, cType:"void (*)(void)")()->()= ct1
letct1ref1:@convention(c, cType:"void (*)(void)")= ct1 // expected-error{{expected type}}
letct1ref2:@convention(c,)()->()= ct1 // expected-error{{expected 'cType' label in 'convention' attribute}}
letct1ref3:@convention(c, cType)()->()= ct1 // expected-error{{expected ':' after 'cType' for 'convention' attribute}}
letct1ref4:@convention(c, cType:)()->()= ct1 // expected-error{{expected string literal containing clang type for 'cType' in 'convention' attribute}}