Synopsis

(Required) An identifier declared in an inner scope shall not hide an identifier declared in an outer scope.

Enabled by default

Yes

Severity/Certainty

Low/Medium

Full description

Identifier names were found that are not distinct in their first 63 characters from other names in an outer scope.

Coding standards

Code examples

The following code example fails the check and will give a warning:

/*          0        1         2         3         4         5         6     */
/*          123456789012345678901234567890123456789012345678901234567890123* */
extern int  n01_param_hides_var__________________________________________63x;
extern int  n02_var_hides_var____________________________________________63x;
void        n03_var_hides_function_______________________________________63x (void) {}

enum E {
            n04_var_hides_enum_const_____________________________________63x
};
#define     n05_var_hides_macro_name_____________________________________63x 123
extern int  n06_type_hides_var___________________________________________63x;

void f1(int n01_param_hides_var__________________________________________63y) {
  int       n02_var_hides_var____________________________________________63y;
  int       n03_var_hides_function_______________________________________63y;
  int       n04_var_hides_enum_const_____________________________________63y;
  int       n05_var_hides_macro_name_____________________________________63y;

  switch(f2()) {
  case 1: {
/*              0        1         2         3         4         5         6     */
/*              123456789012345678901234567890123456789012345678901234567890123* */
    typedef int n06_type_hides_var___________________________________________63y;
    do {
      int       n07_var_var__________________________________________________63x;
      if(f3()) {
	int     n07_var_var__________________________________________________63y = 1;
      }
    } while(f2());
  }
  }
}

The following code example passes the check and will not give a warning about this issue:

int f1 (void) {
/*           0        1         2         3         4         5         6     */
/*           123456789012345678901234567890123456789012345678901234567890123* */
  extern int n01_var_in_same_scope________________________________________63x;
  static int n01_var_in_same_scope________________________________________63y;

  switch(fn()) {
  case 1:
    {
      int    n02_var_in_different_scope___________________________________63a;
    }
    break;
  case 2:
    {
      int    n02_var_in_different_scope___________________________________63b;
    }
    break;
  }
  {
      int    n02_var_in_different_scope___________________________________63c;
  }
  {
      int    n02_var_in_different_scope___________________________________63d;
  }
  return 1;
}

/* identifiers in different name spaces */
/*          0        1         2         3         4         5         6     */
/*          123456789012345678901234567890123456789012345678901234567890123* */
union       n03_var_hides_union_tag______________________________________63x {
  int v1;
  unsigned int v2;
};
enum        n04_var_hides_enum_tag_______________________________________63x {
	    n05_tag_hides_enum_const_____________________________________63x
};
extern int  n06_label_hides_var__________________________________________63x;

int f2(void) {
  int       n03_var_hides_union_tag______________________________________63y;
  int       n04_var_hides_enum_tag_______________________________________63y;
  struct    n05_tag_hides_enum_const_____________________________________63y {
    int ff2;
  };
/*
 0        1         2         3         4         5         6
 123456789012345678901234567890123456789012345678901234567890123* */
 n06_label_hides_var__________________________________________63y:

  switch(f2()) {
  case 1: {
/*              0        1         2         3         4         5         6     */
/*              123456789012345678901234567890123456789012345678901234567890123* */
    do {
      struct    n07_var_hides_struct_tag_____________________________________63x {
	int ff1;
      };
      if(f3()) {
	int     n07_var_hides_struct_tag_____________________________________63y = 1;
      }
    } while(f2());
  }
  }
  return 0;
}