281 lines
		
	
	
		
			8.0 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			281 lines
		
	
	
		
			8.0 KiB
		
	
	
	
		
			C++
		
	
	
	
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wimplicit-fallthrough %s
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int fallthrough(int n) {
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  switch (n / 10) {
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      if (n - 1) {
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        n = 100;
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      } else if (n - 2) {
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        n = 101;
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      } else if (n - 3) {
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        n = 102;
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      }
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    case -1:  // no warning here, ignore fall-through from unreachable code
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      ;
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    case 0: {// expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
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    }
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    case 1:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
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      n += 100         ;
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    case 3:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
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      if (n > 0)
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        n += 200;
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    case 4:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
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      if (n < 0)
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        ;
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    case 5:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
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      switch (n) {
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      case 111:
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        break;
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      case 112:
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        break;
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      case 113:
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        break    ;
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      }
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    case 6:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
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      n += 300;
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    case 66:  // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'break;' to avoid fall-through}}
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    case 67:
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    case 68:
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      break;
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  }
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  switch (n / 15) {
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label_default:
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    default:
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      n += 333;
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      if (n % 10)
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        goto label_default;
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      break;
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    case 70:
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      n += 335;
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      break;
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  }
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  switch (n / 20) {
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    case 7:
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      n += 400;
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      [[clang::fallthrough]];
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    case 9:  // no warning here, intended fall-through marked with an attribute
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      n += 800;
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      [[clang::fallthrough]];
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    default: { // no warning here, intended fall-through marked with an attribute
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      if (n % 2 == 0) {
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        return 1;
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      } else {
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        [[clang::fallthrough]];
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      }
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    }
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    case 10:  // no warning here, intended fall-through marked with an attribute
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      if (n % 3 == 0) {
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        n %= 3;
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      } else {
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        [[clang::fallthrough]];
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      }
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    case 110:  // expected-warning{{unannotated fall-through between switch labels}} but no fix-it hint as we have one fall-through annotation!
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      n += 800;
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  }
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  switch (n / 30) {
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    case 11:
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    case 12:  // no warning here, intended fall-through, no statement between labels
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      n += 1600;
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  }
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  switch (n / 40) {
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    case 13:
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      if (n % 2 == 0) {
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        return 1;
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      } else {
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        return 2;
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      }
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    case 15:  // no warning here, there's no fall-through
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      n += 3200;
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  }
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  switch (n / 50) {
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    case 17: {
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      if (n % 2 == 0) {
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        return 1;
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      } else {
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        return 2;
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      }
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    }
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    case 19: { // no warning here, there's no fall-through
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      n += 6400;
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      return 3;
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    }
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    case 21: { // no warning here, there's no fall-through
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      break;
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    }
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    case 23: // no warning here, there's no fall-through
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      n += 128000;
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      break;
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    case 25: // no warning here, there's no fall-through
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      break;
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  }
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  return n;
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}
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class ClassWithDtor {
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public:
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  ~ClassWithDtor() {}
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};
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void fallthrough2(int n) {
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  switch (n) {
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    case 0:
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    {
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      ClassWithDtor temp;
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      break;
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    }
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    default: // no warning here, there's no fall-through
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      break;
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  }
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}
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void fallthrough3(int n) {
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  switch (n) {
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    case 1:
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      do {
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        return;
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      } while (0);
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    case 2:
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      do {
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        ClassWithDtor temp;
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        return;
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      } while (0);
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    case 3:
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      break;
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  }
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}
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#define MY_SWITCH(X, Y, Z, U, V) switch (X) { case Y: Z; case U: V; }
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#define MY_SWITCH2(X, Y, Z) switch (X) { Y; Z; }
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#define MY_CASE(X, Y) case X: Y
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#define MY_CASE2(X, Y, U, V) case X: Y; case U: V
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int fallthrough_macro1(int n) {
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  MY_SWITCH(n, 13, n *= 2, 14, break)  // expected-warning{{unannotated fall-through between switch labels}}
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  switch (n + 1) {
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    MY_CASE(33, n += 2);
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    MY_CASE(44, break);  // expected-warning{{unannotated fall-through between switch labels}}
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    MY_CASE(55, n += 3);
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  }
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  switch (n + 3) {
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    MY_CASE(333, return 333);
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    MY_CASE2(444, n += 44, 4444, break);  // expected-warning{{unannotated fall-through between switch labels}}
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    MY_CASE(555, n += 33);
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  }
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  MY_SWITCH2(n + 4, MY_CASE(17, n *= 3), MY_CASE(19, break))  // expected-warning{{unannotated fall-through between switch labels}}
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  MY_SWITCH2(n + 5, MY_CASE(21, break), MY_CASE2(23, n *= 7, 25, break))  // expected-warning{{unannotated fall-through between switch labels}}
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  return n;
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}
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void fallthrough_cfgblock_with_null_successor(int x) {
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  (x && "") ? (void)(0) : (void)(1);
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  switch (x) {}
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}
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int fallthrough_position(int n) {
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  switch (n) {
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      [[clang::fallthrough]];  // expected-warning{{fallthrough annotation does not directly precede switch label}}
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      n += 300;
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      [[clang::fallthrough]];  // expected-warning{{fallthrough annotation in unreachable code}}
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    case 221:
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      [[clang::fallthrough]];  // expected-warning{{fallthrough annotation does not directly precede switch label}}
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      return 1;
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      [[clang::fallthrough]];  // expected-warning{{fallthrough annotation in unreachable code}}
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    case 222:
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      [[clang::fallthrough]];  // expected-warning{{fallthrough annotation does not directly precede switch label}}
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      n += 400;
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    case 223:          // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
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      [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
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  }
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  long p = static_cast<long>(n) * n;
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  switch (sizeof(p)) {
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    case 9:
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      n += static_cast<int>(p >> 32);
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      [[clang::fallthrough]];  // no warning here
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    case 5:
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      n += static_cast<int>(p);
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      [[clang::fallthrough]];  // no warning here
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    default:
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      n += 1;
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      break;
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  }
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  return n;
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}
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enum Enum {
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  Value1, Value2
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};
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int fallthrough_covered_enums(Enum e) {
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  int n = 0;
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  switch (e) {
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    default:
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      n += 17;
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      [[clang::fallthrough]];  // no warning here, this shouldn't be treated as unreachable code
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    case Value1:
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      n += 19;
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      break;
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    case Value2:
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      n += 21;
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      break;
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  }
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  return n;
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}
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int fallthrough_targets(int n) {
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  [[clang::fallthrough]]; // expected-error{{fallthrough annotation is outside switch statement}}
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  [[clang::fallthrough]]  // expected-error{{fallthrough attribute is only allowed on empty statements}}
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  switch (n) {
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    case 121:
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      n += 400;
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      [[clang::fallthrough]]; // no warning here, correct target
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    case 123:
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      [[clang::fallthrough]]  // expected-error{{fallthrough attribute is only allowed on empty statements}}
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      n += 800;
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      break;
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    [[clang::fallthrough]]    // expected-error{{fallthrough attribute is only allowed on empty statements}} expected-note{{did you forget ';'?}}
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    case 125:
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      n += 1600;
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  }
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  return n;
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}
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// Fallthrough annotations in local classes used to generate "fallthrough
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// annotation does not directly precede switch label" warning.
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void fallthrough_in_local_class() {
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  class C {
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    void f(int x) {
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      switch (x) {
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        case 0:
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          x++;
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          [[clang::fallthrough]]; // no diagnostics
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        case 1:
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          x++;
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          break;
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      }
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    }
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  };
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}
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namespace PR18983 {
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  void fatal() __attribute__((noreturn));
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  int num();
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  void test() {
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    switch (num()) {
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    case 1:
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      fatal();
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      // Don't issue a warning.
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    case 2:
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      break;
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    }
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  }
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}
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