STR51-CPP: Address false negatives due to incomplete replace modelling

The std::string::replace function uses an internal typedef __const_iterator in
libstdc++, instead of the const_iterator typedef.

Author: lcartey

change_notes/2023-08-03-string-replace.md

@@ -0,0 +1,2 @@
+ - `STR51-CPP`
+   - Address false negatives caused by incomplete modelling of the `std::string::replace()` function.

cpp/common/src/codingstandards/cpp/standardlibrary/String.qll

@@ -45,7 +45,8 @@ class StdBasicString extends ClassTemplateInstantiation {
   Type getConstIteratorType() {
     exists(TypedefType t |
       t.getDeclaringType() = this and
-      t.getName() = "const_iterator" and
+      // Certain compilers user __const_iterator instead of const_iterator.
+      t.getName() = ["const_iterator", "__const_iterator"] and
       result = t
     )
   }

cpp/common/test/includes/standard-library/string

@@ -48,7 +48,8 @@ public:
   size_type length() const noexcept;
 
   typedef __iterator<charT> iterator;
-  typedef __iterator<const charT> const_iterator;
+  typedef __iterator<const charT> __const_iterator;
+  typedef __const_iterator const_iterator;
 
   iterator begin();
   iterator end();
@@ -111,17 +112,17 @@ public:
                         size_type n2);
   basic_string &replace(size_type pos, size_type n1, const charT *s);
   basic_string &replace(size_type pos, size_type n1, size_type n2, charT c);
-  basic_string &replace(const_iterator i1, const_iterator i2,
+  basic_string &replace(__const_iterator i1, __const_iterator i2,
                         const basic_string &str);
-  basic_string &replace(const_iterator i1, const_iterator i2, const charT *s,
+  basic_string &replace(__const_iterator i1, __const_iterator i2, const charT *s,
                         size_type n);
-  basic_string &replace(const_iterator i1, const_iterator i2, const charT *s);
-  basic_string &replace(const_iterator i1, const_iterator i2, size_type n,
+  basic_string &replace(__const_iterator i1, __const_iterator i2, const charT *s);
+  basic_string &replace(__const_iterator i1, __const_iterator i2, size_type n,
                         charT c);
   template <class InputIterator>
-  basic_string &replace(const_iterator i1, const_iterator i2, InputIterator j1,
+  basic_string &replace(__const_iterator i1, __const_iterator i2, InputIterator j1,
                         InputIterator j2);
-  basic_string &replace(const_iterator, const_iterator,
+  basic_string &replace(__const_iterator, __const_iterator,
                         initializer_list<charT>);
 
   size_type copy(charT *s, size_type n, size_type pos = 0) const;