Move the construction of the OOB violation string to after the OOB check fails so that the code is not allocating, concatenating and freeing strings that are never used in regular operation - this can produce a severe performance penalty

Author: ishani

include/cpp2util.h

@@ -1224,14 +1224,14 @@ constexpr auto assert_not_zero(auto&& arg CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAUL
         if constexpr (std::is_signed_v<CPP2_TYPEOF(arg)>) { return std::ssize(x); } \
         else { return std::size(x); } \
     }; \
-    auto msg = "out of bounds access attempt detected - attempted access at index " + std::to_string(arg) + ", "; \
-    if (max() > 0 ) { \
-        msg += "[min,max] range is [0," + std::to_string(max()-1) + "]"; \
-    } \
-    else { \
-        msg += "but container is empty"; \
-    } \
     if (!(0 <= arg && arg < max())) { \
+        auto msg = "out of bounds access attempt detected - attempted access at index " + std::to_string(arg) + ", "; \
+        if (max() > 0 ) { \
+            msg += "[min,max] range is [0," + std::to_string(max()-1) + "]"; \
+        } \
+        else { \
+            msg += "but container is empty"; \
+        } \
         bounds_safety.report_violation(msg.c_str()  CPP2_SOURCE_LOCATION_ARG); \
     } \
     return CPP2_FORWARD(x) [ arg ]; \