Fix #12812 FP variableScope with pointer to buffer (#6540)

Author: chrchr-github

lib/checkother.cpp

@@ -1149,6 +1149,9 @@ bool CheckOther::checkInnerScope(const Token *tok, const Variable* var, bool& us
                     }
                 }
             }
+            const auto yield = astContainerYield(tok);
+            if (yield == Library::Container::Yield::BUFFER || yield == Library::Container::Yield::BUFFER_NT)
+                return false;
         }
     }
 

test/cfg/std.cpp

@@ -5118,3 +5118,13 @@ void constParameterReference_insert(std::list<int>& l, int& r) {
     l.insert(l.end(), r);
     l.insert(l.end(), 5, r);
 }
+
+const char* variableScope_cstr_dummy(const char* q); // #12812
+std::size_t variableScope_cstr(const char* p) {
+    std::string s;
+    if (!p) {
+        s = "abc";
+        p = variableScope_cstr_dummy(s.c_str());
+    }
+    return std::strlen(p);
+}