#30746 (review) introduced unsequenced operations with side-effects - which is undefined behavior, i.e. the right hand side can be evaluated before the left hand side, which happens to mutate it.
0clang++ --analyze -std=c++20 -I./src -I./src/test -I./src/test/fuzz src/test/fuzz/base_encode_decode.cpp src/psbt.cpp
but it didn’t warn about UB.
Grepped for similar ones, but could find any other one in the codebase:
0> grep -rnE --include='*.cpp' --include='*.h' '\b(\w+)\(([^)]*\b(\w+)\b[^)]*)\)\s*==\s*\3\.' .
1
2./src/test/arith_uint256_tests.cpp:373: BOOST_CHECK(R1L.GetHex() == R1L.ToString());
3./src/test/arith_uint256_tests.cpp:374: BOOST_CHECK(R2L.GetHex() == R2L.ToString());
4./src/test/arith_uint256_tests.cpp:375: BOOST_CHECK(OneL.GetHex() == OneL.ToString());
5./src/test/arith_uint256_tests.cpp:376: BOOST_CHECK(MaxL.GetHex() == MaxL.ToString());
6./src/test/fuzz/cluster_linearize.cpp:565: assert(depgraph.FeeRate(best_anc.transactions) == best_anc.feerate);
7./src/test/fuzz/cluster_linearize.cpp:646: assert(depgraph.FeeRate(found.transactions) == found.feerate);
8./src/test/fuzz/cluster_linearize.cpp:765: assert(depgraph.FeeRate(chunk_info.transactions) == chunk_info.feerate);
9./src/test/fuzz/base_encode_decode.cpp:95: assert(DecodeBase64PSBT(psbt, random_string, error) == error.empty());
10./src/test/fuzz/key.cpp:102: assert(pubkey.data() == pubkey.begin());
11./src/test/skiplist_tests.cpp:42: BOOST_CHECK(vIndex[from].GetAncestor(0) == vIndex.data());
12./src/script/signingprovider.cpp:535: ComputeTapbranchHash(node.sub[1]->hash, node.sub[1]->hash) == node.hash) {
13./src/pubkey.h:78: return vch.size() > 0 && GetLen(vch[0]) == vch.size();
14./src/cluster_linearize.h:881: Assume(elem.inc.feerate.IsEmpty() == elem.pot_feerate.IsEmpty());
Hodlinator deduced the UB on Windows in #32135 (comment)
Fixes #32135
