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 31 characters from other names in an outer scope.

Coding standards

Code examples

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

/*          1234567890123456789012345678901********* */
extern int  n01_param_hides_var__________31x;
extern int  n02_var_hides_var____________31x;
void        n03_var_hides_function_______31x (void) {}

enum E {
            n04_var_hides_enum_const_____31x,
};
#define     n05_var_hides_macro_name_____31x 123
extern int  n06_type_hides_var___________31x;

void f1(int n01_param_hides_var__________31y) {
  int       n02_var_hides_var____________31y;
  int       n03_var_hides_function_______31y;
  int       n04_var_hides_enum_const_____31y;
  int       n05_var_hides_macro_name_____31y;

  switch(f2()) {
  case 1: {
    typedef int n06_type_hides_var___________31y;
    do {
      /*     1234567890123456789012345678901********* */
      int n07_var_hides_var_______________31x;
      if(f3()) {
	int  n07_var_hides_var_______________31y = 1;
      }
    } while(f2());
  }
  }
}

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

int f1 (void) {
/*           1234567890123456789012345678901********* */
  extern int n01_var_in_same_scope________31x;
  static int n01_var_in_same_scope________31y;

  switch(fn()) {
  case 1:
    {
      int    n02_var_in_different_scope___31a;
    }
    break;
  case 2:
    {
      int    n02_var_in_different_scope___31b;
    }
    break;
  }
  {
      int    n02_var_in_different_scope___31c;
  }
  {
      int    n02_var_in_different_scope___31d;
  }
  return 0;
}

/* identifiers in different name spaces */
/*          1234567890123456789012345678901********* */
union       n03_var_hides_union_tag______31x {
  int v1;
  unsigned int v2;
};
enum        n04_var_hides_enum_tag_______31x {
	    n05_tag_hides_enum_const_____31x
};
extern int  n06_label_hides_var__________31x;

int f2(void) {
  int       n03_var_hides_union_tag______31y;
  int       n04_var_hides_enum_tag_______31y;
  struct    n05_tag_hides_enum_const_____31y {
    int ff2;
  };
/*
 1234567890123456789012345678901********* */
 n06_label_hides_var__________31y:

  switch(f2()) {
  case 0: {
    do {
      /*     1234567890123456789012345678901********* */
      struct n07_var_hides_struct_tag_____31x {
	int ff1;
      };
      if(f3()) {
	int  n07_var_hides_struct_tag_____31y = 1;
      }
    } while(f2());
  }
  }
  return 0;
}