clang suggests invalid fixits when warning `-Wunguarded-availability-new` is emitted

[ahatanak]

$ cat test.c

int g __attribute__((availability(macosx,introduced=15)));
void foo(int);

void test1(void) {
  int i1 = 1, i2 = g; 
  foo(i2);
  foo(i1);
}

void test2(void) {
  int i1 = g; 
  int i2 = i1;
  foo(i2);
}

$ clang -c test.c -target arm64-apple-macosx14.0.0 -fdiagnostics-parseable-fixits

test.c:5:20: warning: 'g' is only available on macOS 15 or newer [-Wunguarded-availability-new]
    5 |   int i1 = 1, i2 = g; 
      |                    ^
test.c:1:5: note: 'g' has been marked as being introduced in macOS 15 here, but the deployment target is macOS
      14.0.0
    1 | int g __attribute__((availability(macosx,introduced=15)));
      |     ^
test.c:5:20: note: enclose 'g' in a __builtin_available check to silence this warning
    5 |   int i1 = 1, i2 = g; 
      |                    ^
    6 |   foo(i2);
      |           
fix-it:"test.c":{5:3-5:3}:"if (__builtin_available(macOS 15, *)) {\n      "
fix-it:"test.c":{6:11-6:11}:"\n  } else {\n      // Fallback on earlier versions\n  }"
test.c:11:12: warning: 'g' is only available on macOS 15 or newer [-Wunguarded-availability-new]
   11 |   int i1 = g; 
      |            ^
test.c:1:5: note: 'g' has been marked as being introduced in macOS 15 here, but the deployment target is macOS
      14.0.0
    1 | int g __attribute__((availability(macosx,introduced=15)));
      |     ^
test.c:11:12: note: enclose 'g' in a __builtin_available check to silence this warning
   11 |   int i1 = g; 
      |            ^
   12 |   int i2 = i1;
      |               
fix-it:"test.c":{11:3-11:3}:"if (__builtin_available(macOS 15, *)) {\n      "
fix-it:"test.c":{12:15-12:15}:"\n  } else {\n      // Fallback on earlier versions\n  }"

The second and the fourth fixits are incorrect as they would cause compilation errors.

fix-it:"test.c":{6:11-6:11}:"\n } else {\n // Fallback on earlier versions\n }" should be applied on line 7 so that foo(i1); is placed within the same scope as the declaration of i1.

fix-it:"test.c":{12:15-12:15}:"\n } else {\n // Fallback on earlier versions\n }" should be applied on line 13 so that foo(i2); is placed within the same scope as the declaration of i2.