Modify rule S6004: CPP-5608 don't raise for for-range

rules/S6004/cfamily/metadata.json

@@ -1,5 +1,5 @@
 {
-  "title": "\"if\",\"switch\", and range-based for loop initializer should be used to reduce scope of variables",
+  "title": "\"if\" and \"switch\" initializer should be used to reduce scope of variables",
   "type": "CODE_SMELL",
   "code": {
     "impacts": {

rules/S6004/cfamily/rule.adoc

@@ -36,7 +36,7 @@ bool better_init() {
 
 This rule raises an issue when:
 
-- a variable is declared just before a statement that allows variable declaration (`if`, `switch`, or, starting {cpp}20, range-based `for` loop),
+- a variable is declared just before a statement that allows variable declaration (`if`, `switch`),
 - this variable is used in the statement header,
 - there are other statements after this statement where this variable might be used,
 - yet, it is never used after the statement.
@@ -82,32 +82,6 @@ void switchStatement() {
 }
 ----
 
-[source,cpp]
-----
-std::vector<std::vector<int>> getTable();
-void printHeadersBad() {
-  auto rows = getTable(); // Noncompliant in C++20: rows is accessible outside of the loop
-  for (int x : rows[0]) {
-    std::cout << x <<' ';
-  }
-  std::cout << "\n";
-}
-----
-
-Using a temporary to avoid leaking of the variable into the ambient scope creates a bigger problem: an undefined behavior. Even though the lifetime of a temporary returned by the range expression is extended, the life of a temporary within the range expression terminates before the loop begins to execute.
-
-[source,cpp]
-----
-std::vector<std::vector<int>> getTable();
-void printHeadersWorse() {
-  for (int x : getTable()[0]) { // Undefined behavior: return value of getTable() no longer exists in the loop body
-    std::cout << x <<' ';
-  }
-  std::cout << "\n";
-}
-----
-
-
 === Compliant solution
 
 [source,cpp]
@@ -141,15 +115,6 @@ void switchStatement() {
   }
   std::cout << "\n";
 }
-
-std::vector<std::vector<int>> getTable();
-void printHeadersGood() {
-  // Compliant: rows is accessible only inside the loop (this code requires at least C++20)
-  for (auto rows = getTable(); int x : table[0]) {
-    std::cout << x <<' ';
-  }
-  std::cout << "\n";
-}
 ----
 
 === Exceptions