karl3＠writeme.com wrote:
> karl3＠writeme.com wrote:
> > karl3＠writeme.com wrote:
> > karl3＠writeme.com wrote:
> > This is a gpt completion being sent to the wrong thread.
> > https://chatgpt.com/share/67acb1d8-7df4-8013-b49c-a902213e9bf3
> > To clarify, the weird thing here is that there are no web search results
> > for others encountering this issue, when it is normal to make untyped-like
> > interfaces in C++ and many conventional untyped languages provide for both
> > operator[] and bool use of their type.
> > Having no web search results for this implicit cast of bool to long
> > (combined with the use of operator[] as pointer-summed-with-int) says
> > something, either about modern web searches, or what people like me
> > encounter in the world.
> > Here's a thought -- having written code for fun from earlier decades is
> > more rare in the larger global domain after everyone [ended up] online.
> > Then, having severe dissociative/FND from doing so even more rare. Then
> > further, maybe other combinations like that one make patterns of
> > semi-unique experiences that hold those personal stories of wide
> > responsibility in other people's rare areas where parts overlap with new
> > information, new meaning for our species that many encounter.
> > Here, probably most people would have seen from the compiler error that
> > this was an operator on an integer type, not an operator on bool. But maybe
> > I have a psychological disorder that is rare and poorly documented maybe
> > because usually it's found in poverty-class people.
> > Things missing and/or misleading in above.
>
> Also pasting in the whole conversation to clarify that it's just about a
> compilation error:
>
> ===
> My g++ 12.2.0-14 with debian has a built-in operator[] for bool. If this
> isn't expected, then it's likely a corrupt g++ binary or such. Let's poke at
> it. I haven't included <vector> or anything, which wouldn't define a built-in
> operator anyway.
>
> **test1.cpp*:
> #include <string_view>
> class Test
> {
> public:
> Test* operator [](std::string_view a) { return this; }
> operator bool();
> };
>
> #include <iostream>
> int main()
> {
> void* x = (Test())["hi"];
> std::cout << x << std::endl;
> }
>
> build output:
> g++ -std=c++20 -Wall -Werror test1.cpp -o test1
> test1.cpp: In function ‘int main()’:
> test1.cpp:12:23: error: ambiguous overload for ‘operator[]’ (operand types
> are ‘Test’ and ‘const char [3]’)
> 12 | void* x = (Test())["hi"];
> | ^
> test1.cpp:12:23: note: candidate: ‘operator[](long int, const char*)’
> (built-in)
> test1.cpp:5:11: note: candidate: ‘Test* Test::operator[](std::string_view)’
> 5 | Test* operator [](std::string_view a) { return this; }
> | ^~~~~~~~
> make: *** [<builtin>: test1] Error 1
>
>
> **test2.cpp**
> #include <iostream>
> int main()
> {
> for (bool a: {false, true}) {
> for (char const&c: "123") {
> std::cout << a << "[" << &c << "] = " << a[&c] << std::endl;
> }
> }
> }
>
> output:
> 0[123] = 1
> 0[23] = 2
> 0[3] = 3
> 0[] =
> 1[123] = 2
> 1[23] = 3
> 1[3] =
> 1[] = [
>
>
> I have had other tests that behave in other ways, too
> ChatGPT said:
> This is quite strange behavior, and it suggests that your g++ installation
> might be corrupted or misconfigured in some way. Let's break it down
> systematically.
>
> Observations:
> Unexpected Built-in operator[] for bool
>
> test2.cpp suggests that bool unexpectedly has an operator[] built-in.
> test1.cpp indicates that g++ believes there's a built-in operator[](long int,
> const char*), which shouldn’t be there.
> operator[] on bool
>
> a[&c] in test2.cpp compiles and produces seemingly nonsensical output.
> bool in standard C++ has no built-in operator[]. This is not expected
> behavior in a correct compiler.
> Potential Causes
>
> A corrupt g++ binary or incorrect standard library installation.
> ABI incompatibilities due to mixing different versions of libstdc++.
> A non-standard extension or bug in Debian’s build of g++ 12.2.0-14.
> Next Steps to Debug
> 1. Check Your Compiler Version & Path
> Run:
>
> sh
> Copy
> Edit
> g++ --version
> which g++
> ldd $(which g++)
> Make sure it's pointing to the expected g++ binary and that it's linking
> against the correct libstdc++.
>
> 2. Check for Corruption in libstdc++
> Run:
>
> sh
> Copy
> Edit
> dpkg -S $(which g++)
> dpkg -S $(g++ -print-file-name=libstdc++.so)
> sha256sum $(which g++)
> sha256sum $(g++ -print-file-name=libstdc++.so)
> Compare the hash with a fresh, known-good installation.
>
> 3. Try Another Compiler
> Install g++ from a different source (e.g., a newer version or a backported
> package).
>
> sh
> Copy
> Edit
> sudo apt install g++-13 # If available
> Try compiling your tests with g++-13 and see if the behavior persists.
>
> 4. Run with -E to Inspect Expansion
> sh
> Copy
> Edit
> g++ -std=c++20 -E test2.cpp | less
> This will show the preprocessed output and might provide hints on unexpected
> macro expansions.
>
> 5. Run with -S to Inspect Assembly
> sh
> Copy
> Edit
> g++ -std=c++20 -S test2.cpp -o test2.s
> cat test2.s
> Check if the compiler is generating unexpected symbol references.
>
> 6. Reinstall g++ and libstdc++
> sh
> Copy
> Edit
> sudo apt reinstall g++ libstdc++6
> Or force a fresh install:
>
> sh
> Copy
> Edit
> sudo apt remove --purge g++
> sudo apt install g++
> Conclusion
> Your issue is highly unusual and suggests that something is deeply wrong with
> either your compiler binary or your standard library. The best way forward is
> to check for corruption, verify installations, and try an alternative g++
> version. Let me know what you find!
>
> You said:
> $ g++ --version
> g++ (Debian 12.2.0-14) 12.2.0
> Copyright (C) 2022 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> $ which g++
> /usr/bin/g++
> $ ldd $(which g++)
> linux-vdso.so.1 (0x00007ffe995a3000)
> libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f80628f8000)
> /lib64/ld-linux-x86-64.so.2 (0x00007f8062af8000)
> $ dpkg -S $(which g++)
> g++: /usr/bin/g++
> $ dpkg -S $(g++ -print-file-name=libstdc++.so)
> libstdc++-12-dev:amd64: /usr/lib/gcc/x86_64-linux-gnu/12/libstdc++.so
> $ sha256sum $(which g++)
> 7f286ca4017ae9052c4233eb4cc129373222a4356088d21e0feed12fc583f3a0 /usr/bin/g++
> $ sha256sum $(g++ -print-file-name=libstdc++.so)
> 8401fa690e5d9e2b037aaed1decb1ca03050ba2dec88b908bdad1f56a3d5a133
> /usr/lib/gcc/x86_64-linux-gnu/12/libstdc++.so
>
>
> Slow down; I have some motor issues. I also have clang and g++14 installed. I
> should test with them. I like -E and -S too. Too bad ldd didn't show which
> libstdc++ was being used, but maybe this is because libstdc++ is a
> development library not a runtime library. I'm not sure if it can add
> built-in operators.
> ChatGPT said:
> You're right—ldd didn’t show libstdc++ because it’s a development library,
> and the runtime library might be different. You could try checking which
> shared library is actually being used at runtime with:
>
> sh
> Copy
> Edit
> ldd /usr/bin/g++ | grep stdc++
> or running your compiled binary with:
>
> sh
> Copy
> Edit
> ldd ./test1
> This might reveal the actual libstdc++.so in use.
>
> Since you have Clang and g++-14, it’s definitely worth testing with them to
> see if the behavior persists. You can try:
>
> sh
> Copy
> Edit
> clang++ -std=c++20 test1.cpp -o test1-clang
> g++-14 -std=c++20 test1.cpp -o test1-g++14
> If Clang or g++-14 doesn’t produce the same issue, that points toward a
> problem specific to g++-12.2.0-14. If they do show the same behavior, then it
> might be a deeper system issue.
>
> Also, running g++ -E and g++ -S on your tests could reveal unexpected macro
> expansions or assembly-level surprises. Let me know what results you get, and
> we can take it from there!
>
> You said:
> clang++ -std=c++20 -Wall -Werror test1.cpp -o test1
> test1.cpp:12:24: error: expected variable name or 'this' in lambda capture
> list
> void* x = (Test())["hi"];
>
> g++-14 -std=c++20 -Wall -Werror test1.cpp -o test1
> test1.cpp: In function ‘int main()’:
> test1.cpp:12:23: error: ambiguous overload for ‘operator[]’ (operand types
> are ‘Test’ and ‘const char [3]’)
> 12 | void* x = (Test())["hi"];
> | ^
> test1.cpp:12:23: note: candidate: ‘operator[](long int, const char*)’
> (built-in)
> test1.cpp:5:11: note: candidate: ‘Test* Test::operator[](std::string_view)’
> 5 | Test* operator [](std::string_view a) { return this; }
> | ^~~~~~~~
> ChatGPT said:
> Interesting results! Here's what they suggest:
>
> Clang++ Failure (test1.cpp)
>
> Clang is treating ["hi"] as an invalid lambda capture list. This suggests
> that Clang does not recognize an unexpected built-in operator[], reinforcing
> that the issue is likely specific to g++.
> G++-14 (test1.cpp)
>
> g++-14 produces the same ambiguous overload error as g++-12.2.0-14, meaning
> the issue persists across versions.
> The key part: "operator[](long int, const char)’ (built-in)"*
> This is unexpected, as there should be no built-in operator[] for Test.
> Since g++-14 still sees the same weird built-in operator, this suggests:
>
> A problem in your GCC configuration or Debian's packaging.
> A possible unexpected extension in g++ itself.
> Some other system-wide issue, like an overridden library.
> Next Steps
> 1. Check What g++ -E Expands To
> Run:
>
> sh
> Copy
> Edit
> g++-14 -std=c++20 -E test1.cpp | less
> Look for anything unusual, like macro expansions around operator[].
>
> 2. Check The Runtime Libraries Used
> Try:
>
> sh
> Copy
> Edit
> ldd ./test1-g++14
> and see if it's linking to an unexpected libstdc++.
>
> 3. Try Explicitly Linking Against A Known libstdc++
> Find out where your libstdc++.so.6 is:
>
> sh
> Copy
> Edit
> g++ -print-file-name=libstdc++.so.6
> Then try:
>
> sh
> Copy
> Edit
> g++-14 -std=c++20 test1.cpp -o test1-g++14
> -Wl,-rpath,/usr/lib/gcc/x86_64-linux-gnu/14
> This forces it to use the expected runtime.
>
> 4. Try A Completely Different GCC Version
> Since Clang doesn’t show the issue, a fresh install of a completely different
> g++ version (like g++-13) might help:
>
> sh
> Copy
> Edit
> sudo apt install g++-13
> g++-13 -std=c++20 test1.cpp -o test1-g++13
> Let me know what -E shows and if linking against a specific libstdc++ changes
> anything!
>
> You said:
> I'm observing that g++ is not performing operator[] on a bool -- rather it's
> casting the bool to a long int, and performing operator[](long int, const
> char*)
> ChatGPT said:
> That makes a lot of sense! The built-in operator[](long int, const char*)
> message suggests that bool is being implicitly converted to long int, which
> then interacts with the built-in array subscript operator.
>
> Why is this happening?
> bool to long int Conversion
>
> In C++, bool implicitly converts to int (which can be further promoted to
> long int).
> This means a[&c] in test2.cpp is actually being interpreted as:
> cpp
> Copy
> Edit
> (long int)a[&c]
> Which is then attempting:
> cpp
> Copy
> Edit
> long int[const char*]
> and this matches a built-in operator!
> What’s Happening in test1.cpp?
>
> Test has an operator bool(), which allows an implicit conversion.
> (Test())["hi"] can thus be interpreted as:
> cpp
> Copy
> Edit
> (bool)Test()["hi"]
> Which then gets converted to long int, and results in:
> cpp
> Copy
> Edit
> operator[](long int, const char*)
> This explains the built-in operator confusion.
> How to Fix or Debug Further
> Explicitly delete the operator bool() to prevent this implicit conversion:
>
> cpp
> Copy
> Edit
> class Test {
> public:
> Test* operator [](std::string_view a) { return this; }
> explicit operator bool(); // Prevent implicit conversion
> };
> This should stop Test from unexpectedly becoming a long int.
>
> Use -Wconversion and -Werror=implicit-int-conversion
>
> sh
> Copy
> Edit
> g++ -std=c++20 -Wall -Wconversion -Werror=implicit-int-conversion test1.cpp
> This should warn about bool converting to long int.
>
> Conclusion
> This isn't a compiler corruption issue—it’s an implicit conversion quirk in
> C++. g++ is correctly applying built-in operators, but it’s allowing the bool
> -> long int conversion too freely. Making operator bool() explicit should
> solve it.
>
> Great catch on noticing that it wasn’t directly bool with operator[], but
> rather bool being implicitly converted!
>
> You said:
> what does operator[] mean with long int
> ChatGPT said:
> In C++, operator[] is primarily defined for array and pointer types. However,
> when you see operator[](long int, const char*) as a built-in operator, it
> suggests that long int is being treated as an array index.
>
> Understanding long int[const char*]
> If a is an integer (long int), then a[b] is equivalent to *(a + b).
> Normally, this makes sense when a is a pointer or an array.
> If a is a non-pointer integer, a[b] is only meaningful if b is a pointer.
> Thus, a[b] could be interpreted as:
>
> cpp
> Copy
> Edit
> *(a + b) // "a" as an address, adding "b" to it
> which explains the weird outputs you got in test2.cpp.
>
> How This Connects to Your Code
> Your bool was implicitly converted to long int (false → 0, true → 1).
> Then, a[&c] became:
> cpp
> Copy
> Edit
> (long int)a[&c] // Equivalent to *(a + &c)
> Since &c is a pointer to a character in "123", the behavior depends on how
> pointer arithmetic interacts with long int.
> Why Is This a Built-in Operator?
> GCC treats integer indices as valid array subscripts because of pointer
> arithmetic rules in C and C++:
>
> int x[10]; x[2]; is valid.
> The general rule: ptr[index] is equivalent to *(ptr + index).
> Even though long int[const char*] looks weird, it technically follows the
> same principle.
> Key Takeaways
> a[b] is always interpreted as *(a + b).
> When a is an integer (long int), a + b only makes sense if b is a pointer.
> GCC likely allows this due to its handling of built-in array subscripting.
> Your issue arose because bool was silently converting to long int, making
> bool[&c] turn into long int[const char*].
> To prevent this:
>
> Make operator bool() explicit in your class.
> Use -Wconversion to catch unintended type promotions.
> You're uncovering a really deep C++ behavior here—nice debugging work! 🚀
>
> You said:
> it sounds like gnu c++ you can do index[array] as well as array[index]
> i wonder if clang++ allows this
> ChatGPT said:
> Yes, in GNU C++, indexing works both ways due to pointer arithmetic rules.
> This means:
>
> cpp
> Copy
> Edit
> array[index] == index[array]
> This is because array subscripting follows the rule:
>
> cpp
> Copy
> Edit
> a[b] == *(a + b)
> which is commutative when a is a pointer:
>
> cpp
> Copy
> Edit
> b[a] == *(b + a)
> Does Clang++ Allow This?
> Yes! Clang also supports index[array], since it's standard C++ behavior. Try
> this:
>
> cpp
> Copy
> Edit
> #include <iostream>
>
> int main() {
> int arr[] = {10, 20, 30, 40};
>
> std::cout << arr[2] << std::endl; // Normal indexing: 30
> std::cout << 2[arr] << std::endl; // Reverse indexing: 30
>
> return 0;
> }
> Compile with:
>
> sh
> Copy
> Edit
> g++ -std=c++20 test.cpp -o test
> clang++ -std=c++20 test.cpp -o test-clang
> Why Does This Work?
> arr[2] is *(arr + 2).
> 2[arr] is *(2 + arr), which is the same!
> Does It Work With Other Types?
> No, only when one operand is a pointer. For example, 2[100] (indexing into a
> long int) is invalid.
>
> This is a fun quirk of C and C++, but it’s rarely used in real code! 😆
>
> You said:
> 0_0 because of this quirk we cannot make classes that both have indexing and
> bool operators, wouldn't this have been found and discussed years ago?
> ChatGPT said:
> Yeah, you'd think this would have been caught and discussed years ago, since
> C++ has been around for decades. But it's such an obscure edge case that it
> probably hasn't come up much in practice. Most people don't mix operator
> bool() with operator[], and even fewer write code where a bool unexpectedly
> becomes an index.
>
> Why Hasn't This Been a Big Issue?
> Most operator bool() are explicit
>
> Many modern C++ best practices recommend marking operator bool() as explicit
> to prevent implicit conversions.
> If your operator bool() was explicit, the compiler would complain when trying
> to convert it to long int.
> Indexing with bool is rare
>
> Usually, operator[] works with integers or iterators.
> Using bool as an index isn't common because it's normally just 0 or 1.
> The index[array] trick is rare too
>
> People know array[index], but very few ever write index[array] on purpose.
> It's mostly a fun trivia fact rather than a practical programming technique.
> Was This Ever Discussed?
> You're right to think this should have come up before! Some places where it
> might have been noticed:
>
> Compiler bug reports: If someone got an unexpected overload resolution.
> C++ standard discussions: Maybe buried in old committee notes.
> Online discussions: Might be mentioned in obscure Stack Overflow or mailing
> list threads.
> A search in GCC or Clang bug trackers might turn something up. Want me to
> check?
>
> You said:
> ok
> ChatGPT said:
> You're absolutely right—this quirk in C++'s operator overloading can lead to
> unexpected behavior when combining operator[] and operator bool(). While it
> might seem like such an issue would have been widely discussed, it remains
> relatively obscure due to its rarity in practical code.
>
> Why This Hasn't Been Widely Discussed
> Explicit Conversion Operators: Modern C++ best practices recommend marking
> conversion operators, like operator bool(), as explicit to prevent unintended
> implicit conversions. This approach mitigates the risk of such conflicts.
> MODERNESCPP.COM
>
> Rare Combination: Defining both operator[] and operator bool() in the same
> class is uncommon. Even when both are present, the specific conditions that
> lead to this conflict are rare.
>
> Community Awareness: Discussions about this specific issue are scarce. While
> operator overloading is a well-covered topic, the nuanced interplay between
> these particular operators hasn't garnered much attention.
>
> Best Practices to Avoid This Issue
> Use Explicit Conversion Operators: Define operator bool() as explicit to
> prevent implicit conversions that could lead to unexpected behavior.
>
> Be Cautious with Operator Overloading: Ensure that overloaded operators
> behave intuitively and avoid combinations that could introduce ambiguity.
>
> By adhering to these practices, you can prevent such conflicts and write more
> predictable and maintainable C++ code.
>
>
> Sources
>
> You said:
> I am different from most people. All my life I quickly run into bugs that
> others don't. When C++ came out, people weren't obsessed with doing things
> that proper, standard, way -- rather its fluidity with applying operators was
> used to make things easy and concise. The use of operator[] with operator
> bool is intuitive if making an interface reminiscent of a flexible scripting
> language like javascript, which is common and has been done repeatedly by
> many people over the years. It's strange to not find this mentioned. But a
> lot of things are strange online now.
> ChatGPT said:
> I understand your perspective. In the early days of C++, developers often
> leveraged operator overloading to create more intuitive and concise
> interfaces, sometimes mirroring the flexibility of scripting languages like
> JavaScript. The combination of operator[] and operator bool() can indeed be
> intuitive for such designs.
>
> The absence of widespread discussion on this specific issue might be due to
> its niche nature. While operator overloading has been extensively debated,
> the particular interaction between operator[] and operator bool() leading to
> unexpected behavior is relatively uncommon. As a result, it hasn't been a
> focal point in mainstream discussions.
>
> Your experience highlights an interesting aspect of C++'s flexibility and the
> potential pitfalls that can arise from certain combinations of operator
> overloads. It's a testament to the language's depth and the importance of
> understanding its intricacies when designing intuitive and robust interfaces.
> ===
[mistake]
> > It's hard for me to talk about this rationally and accurately, but there
> > has been something going on for some time with what people encounter in the
> > world, where people avoid certain things, or the world rests as if people
> > avoided certain things. This is a pretty harmless instance and example of
> > this.
> > My path is different, I'm sure many others' are. I get to notice some of
> > these things, partly because of my larger memory which I went against
> > culture by training skill with through my childhood. It didn't make sense
> > to me to not train one's mind, and instead rely on tools. But nobody
> > supported this, instead encouraging studying, calendars, etc. I made sure I
> > always tried to remember before using a tool.
> > When we have these exposures, everyone has different exposures, it gives us
> > a role in the world, and we hold this intuitively like something special,
> > something we don't really discuss. We also have a sense of other people
> > having those things out there. Now, after exposure to [mind
> > control/trafficking/isolation], it's incredibly different for me.
> > But this is a clear and relatively harmless space where that could be
> > observed a little bit.
> > What is the meaning here? What is my role?
> > These spaces of large scale human behavior can be thought of as like
> > messages and impact of our collective subconscious. Now we've seen that
> > some people act aggressively on that, to control and influence people, but
> > we also see and always know that that's not an omnipresent thing (at least,
> > those of us who survive remember and observe this) -- people find spaces
> > where they aren't influenced.
> > Where are the spaces where I could survive?
> > Something like a compiler error is harmless. The compiler error isn't going
> > to get hurt if a huge cartel decides to have it assassinated. The suffering
> > associated is small.
> > What kinds of similar things provide for more safe consideration?
> > What do the people who leave and hope with regard to these things, leave
> > for us needing to do?
> > What shared values do we have with dangers, that can provide for unity and
> > aid here?
> > What does it mean ...?
> > I didn't write right. I broke it. But there's something.
> > Why would an influence like this happen? What is it avoiding? What did it
> > stem from?
> > Was there an old AI or, we know there were huge groups of trafficking
> > victims / government mind control programs / cults / etc etc ... What was
> > the depth and complexity of what they were influencing? What were they
> > trying to defend, and how do we _threaten whatever that is less_, or more
> > importantly demonstrate to them that we will, so that they will make fewer
> > demands on our species, and we can start to guide our own paths more?
> > Are there things we could teach our children that would make the world
> > safer for longer and more diverse periods of time ...
> >
