clang/test/SemaObjC/arc-repeated-weak.mm

// RUN: %clang_cc1 -fsyntax-only -fobjc-runtime-has-weak -fobjc-arc -fblocks -Wno-objc-root-class -Warc-repeated-use-of-weak -verify %s

@interface Test {
@public
  Test *ivar;
}
@property(weak) Test *weakProp;
@property(strong) Test *strongProp;

- (__weak id)implicitProp;

+ (__weak id)weakProp;
@end

extern void use(id);
extern id get();
extern bool condition();
#define nil ((id)0)

void sanity(Test *a) {
  use(a.weakProp); // expected-warning{{weak property is accessed multiple times in this function but may be unpredictably set to nil; assign to a strong variable to keep the object alive}}
  use(a.weakProp); // expected-note{{also accessed here}}

  use(a.strongProp);
  use(a.strongProp); // no-warning

  use(a.weakProp); // expected-note{{also accessed here}}
}

void singleUse(Test *a) {
  use(a.weakProp); // no-warning
  use(a.strongProp); // no-warning
}

void assignsOnly(Test *a) {
  a.weakProp = get(); // no-warning

  id next = get();
  if (next)
    a.weakProp = next; // no-warning
}

void assignThenRead(Test *a) {
  a.weakProp = get(); // expected-note{{also accessed here}}
  use(a.weakProp); // expected-warning{{weak property is accessed multiple times}}
}

void twoVariables(Test *a, Test *b) {
  use(a.weakProp); // no-warning
  use(b.weakProp); // no-warning
}

void doubleLevelAccess(Test *a) {
  use(a.strongProp.weakProp); // expected-warning{{weak property may be accessed multiple times in this function but may be unpredictably set to nil; assign to a strong variable to keep the object alive}}
  use(a.strongProp.weakProp); // expected-note{{also accessed here}}
}

void doubleLevelAccessIvar(Test *a) {
  use(a.strongProp.weakProp); // expected-warning{{weak property may be accessed multiple times}}
  use(a.strongProp.weakProp); // expected-note{{also accessed here}}
}

void implicitProperties(Test *a) {
  use(a.implicitProp); // expected-warning{{weak property is accessed multiple times}}
  use(a.implicitProp); // expected-note{{also accessed here}}
}

void classProperties() {
  use(Test.weakProp); // expected-warning{{weak property is accessed multiple times}}
  use(Test.weakProp); // expected-note{{also accessed here}}
}

void classPropertiesAreDifferent(Test *a) {
  use(Test.weakProp); // no-warning
  use(a.weakProp); // no-warning
  use(a.strongProp.weakProp); // no-warning
}


void assignToStrongWrongInit(Test *a) {
  id val = a.weakProp; // expected-note{{also accessed here}}
  use(a.weakProp); // expected-warning{{weak property is accessed multiple times}}
}

void assignToStrongWrong(Test *a) {
  id val;
  val = a.weakProp; // expected-note{{also accessed here}}
  use(a.weakProp); // expected-warning{{weak property is accessed multiple times}}
}

void assignToStrongOK(Test *a) {
  if (condition()) {
    id val = a.weakProp; // no-warning
    (void)val;
  } else {
    id val;
    val = a.weakProp; // no-warning
    (void)val;
  }
}

void assignToStrongConditional(Test *a) {
  id val = (condition() ? a.weakProp : a.weakProp); // no-warning
  id val2 = a.implicitProp ?: a.implicitProp; // no-warning
}

void testBlock(Test *a) {
  use(a.weakProp); // no-warning

  use(^{
    use(a.weakProp); // expected-warning{{weak property is accessed multiple times in this block}}
    use(a.weakProp); // expected-note{{also accessed here}}
  });
}


@interface Test (Methods)
@end

@implementation Test (Methods)
- (void)sanity {
  use(self.weakProp); // expected-warning{{weak property is accessed multiple times in this method but may be unpredictably set to nil; assign to a strong variable to keep the object alive}}
  use(self.weakProp); // expected-note{{also accessed here}}
}

- (void)doubleLevelAccessForSelf {
  use(self.strongProp.weakProp); // expected-warning{{weak property is accessed multiple times}}
  use(self.strongProp.weakProp); // expected-note{{also accessed here}}

  use(self->ivar.weakProp); // expected-warning{{weak property is accessed multiple times}}
  use(self->ivar.weakProp); // expected-note{{also accessed here}}
}

- (void)distinctFromOther:(Test *)other {
  use(self.strongProp.weakProp); // no-warning
  use(other.strongProp.weakProp); // no-warning

  use(self->ivar.weakProp); // no-warning
  use(other->ivar.weakProp); // no-warning
}
@end


class Wrapper {
  Test *a;

public:
  void fields() {
    use(a.weakProp); // expected-warning{{weak property is accessed multiple times in this function but may be unpredictably set to nil; assign to a strong variable to keep the object alive}}
    use(a.weakProp); // expected-note{{also accessed here}}
  }

  void distinctFromOther(Test *b, const Wrapper &w) {
    use(a.weakProp); // no-warning
    use(b.weakProp); // no-warning
    use(w.a.weakProp); // no-warning
  }

  static void doubleLevelAccessField(const Wrapper &x, const Wrapper &y) {
    use(x.a.weakProp); // expected-warning{{weak property may be accessed multiple times}}
    use(y.a.weakProp); // expected-note{{also accessed here}}
  }
};


// -----------------------
// False positives
// -----------------------

// Most of these would require flow-sensitive analysis to silence correctly.

void assignAfterRead(Test *a) {
  if (!a.weakProp) // expected-warning{{weak property is accessed multiple times}}
    a.weakProp = get(); // expected-note{{also accessed here}}
}

void assignNil(Test *a) {
  if (condition())
    a.weakProp = nil; // expected-note{{also accessed here}}

  use(a.weakProp); // expected-warning{{weak property is accessed multiple times}}
}

void branch(Test *a) {
  if (condition())
    use(a.weakProp); // expected-warning{{weak property is accessed multiple times}}
  else
    use(a.weakProp); // expected-note{{also accessed here}}
}

void doubleLevelAccess(Test *a, Test *b) {
  use(a.strongProp.weakProp); // expected-warning{{weak property may be accessed multiple times}}
  use(b.strongProp.weakProp); // expected-note{{also accessed here}}

  use(a.weakProp.weakProp); // no-warning
}

void doubleLevelAccessIvar(Test *a, Test *b) {
  use(a->ivar.weakProp); // expected-warning{{weak property may be accessed multiple times}}
  use(b->ivar.weakProp); // expected-note{{also accessed here}}

  use(a.strongProp.weakProp); // no-warning
}